JP2020048190A - Imaging unit and imaging apparatus - Google Patents

Abstract

To provide an imaging unit and an imaging apparatus, capable of reducing an influence of magnetic field noise to improve image quality.SOLUTION: An imaging unit 400 has an imaging element 300 including analog ground wiring 330 and a wiring board 500 on which the imaging element 300 is mounted. The wiring board 500 has ground wiring 571 and ground wiring 572. The ground wiring 571 forms a closed loop L1 with the analog ground wiring 330 when viewed in a Y direction. The ground wiring 571 and the ground wiring 572 are connected by only one via conductor 511.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an imaging unit having an imaging device.

  An imaging device such as a digital video camera or a digital still camera includes an imaging unit having an imaging element. In recent years, the ISO sensitivity of an image sensor has been increased, and even when an image is captured in a scene with a small amount of light such as a night scene, a clearer image is generated. However, as the ISO sensitivity of the image sensor increases, the sensitivity to weak noise that has not been a problem in the past has also increased. As a result, the problem that the image sensor is affected by noise and the image is disturbed has become apparent.

  Patent Literature 1 discloses an imaging unit that reduces magnetic field noise that reaches an imaging chip by canceling magnetic field noises radiated from a power supply pattern and a ground pattern of a mounting substrate by an operation of a processing circuit of the imaging chip. It has been disclosed.

JP 2017-103517 A

  However, the magnetic field noise that reaches the image sensor is not limited to that caused by the operation of the image sensor itself. For example, there is a digital single-lens reflex camera or the like in which a lens driving coil is provided inside a lens barrel detachable from a camera body. In some cases, a sensor driving coil is provided inside the camera body. Magnetic field noise also occurs from inductor elements such as these coils. In addition, magnetic field noise may fly from outside to the image sensor.

  As described above, the image sensor is exposed to the magnetic field noise due to various factors, and it is difficult to prevent the magnetic field noise from reaching the image pickup unit having the image sensor.

  An object of the present invention is to improve image quality.

  The imaging unit of the present invention includes an imaging element having an analog circuit including analog ground wiring, a wiring board on which the imaging element is mounted, and the wiring board is connected to the analog ground wiring, and viewed from a side. A first ground line forming a closed loop with the analog ground line, and a second ground line connected to the first ground line by only a first via conductor.

  According to the present invention, the quality of an image is improved.

FIG. 1 is a schematic diagram of a camera that is an example of an imaging device according to a first embodiment. FIG. 1 is a schematic diagram of a camera that is an example of an imaging device according to a first embodiment. FIG. 2 is a circuit diagram showing an example of a configuration of the image sensor according to the first embodiment. FIG. 2 is a schematic plan view of the imaging unit according to the first embodiment. FIG. 2 is a cross-sectional view of the imaging unit according to the first embodiment. FIG. 2A is a plan view of a conductor layer of the wiring board according to the first embodiment. FIG. 2B is a plan view of a conductor layer of the wiring board according to the first embodiment. FIG. 9 is a cross-sectional view of the imaging unit according to the second embodiment. FIG. 10 is a sectional view of an imaging unit according to a third embodiment. FIG. 14 is a sectional view of an imaging unit according to a fourth embodiment. FIG. 14 is a sectional view of an imaging unit according to a fifth embodiment. (A) is a top view of the conductor layer of the wiring board which concerns on 5th Embodiment. (B) is a schematic diagram of the image sensor viewed from above. FIG. 14 is a sectional view of an imaging unit according to a sixth embodiment. Sectional drawing of the imaging unit which concerns on 7th Embodiment. The top view of the conductor layer of the wiring board concerning 7th Embodiment. Sectional drawing of the imaging unit which concerns on 8th Embodiment. The top view of the conductor layer of the wiring board concerning 8th Embodiment. Sectional drawing of the imaging unit which concerns on 9th Embodiment. The top view of the conductor layer of the wiring board concerning 9th Embodiment. Sectional drawing of the imaging unit concerning 10th Embodiment. Sectional drawing of the imaging unit concerning 10th Embodiment. The top view of the conductor layer of the wiring board concerning 10th Embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 and FIG. 2 are schematic diagrams of a camera 100 as an example of the imaging device according to the first embodiment. FIG. 1 is a diagram schematically illustrating the front of the camera 100, and FIG. 2 is a diagram schematically illustrating the cross section of the camera 100. The camera 100 is a digital camera such as a digital still camera and a digital video camera. The camera 100 may be a camera in which a lens and a camera body are integrated. However, in the first embodiment, the camera 100 is a digital single-lens camera, and includes a camera body 101 and a lens barrel 200 detachable from the camera body 101.

  The camera body 101 includes an outer case 102 serving as a housing. The outer case 102 has a mount 111 to which the lens barrel 200 can be attached and detached. An imaging unit 400 including an imaging element 300 having a light receiving surface 301 and a wiring board 500 on which the imaging element 300 is mounted is arranged inside the outer case 102. A direction perpendicular to the light receiving surface 301 is defined as a Z direction.

  The imaging unit 400 is held by the metal frame 103. Inside the metal frame 103, a plurality of coils 104 for mechanically driving the imaging unit 400, which is an example of an inductor element, are arranged. Each coil 104 generates a Lorentz force to drive the imaging unit 400 in a direction opposite to the direction of camera shake. The imaging element 300 is an imaging chip such as a CMOS image sensor or a CCD image sensor, and has a quadrangular shape, specifically a rectangular shape when viewed in a Z direction perpendicular to the light receiving surface 301 of the imaging device 300. I have. In the direction parallel to the light receiving surface 301 of the image sensor 300, the long side direction of the image sensor 300 is defined as the X direction, and the short side direction is defined as the Y direction. In the first embodiment, the Y direction is the first direction, and the Z direction is the second direction. The image sensor 300 photoelectrically converts the light image formed on the light receiving surface 301 and outputs a pixel signal to the wiring board 500.

  The lens barrel 200 is supported by the lens housing 201 and the lens housing 201, and forms an optical image on the light receiving surface 301 of the image sensor 300 when the lens barrel 200 is mounted on the outer case 102. 202. The lens barrel 200 includes a coil 203 that is disposed inside the lens housing 201 and that mechanically drives an optical system 202, which is an example of an inductor element. The optical system 202 has a lens 211 arranged on the light incident side of the lens housing 201 and a lens 212 arranged on the light emitting side. The lens housing 201 is provided with a ring mount 204. The lens 212 is supported by the ring mount 204. The coil 203 is arranged so as not to block the optical path from the optical system 202 to the light receiving surface 301 of the image sensor 300, that is, to be located on the outer periphery of the image sensor 300 when viewed from the front as shown in FIG.

  The coils 104 and 203 operate when an alternating current having a frequency in a kHz band, that is, a frequency of 1 kHz or more and less than 1 MHz is supplied. The coils 104 and 203 generate a magnetic flux around when the alternating current is supplied. This magnetic flux becomes magnetic field noise for the image sensor 300. Although the direction of the magnetic flux is indicated by the dashed arrow in FIG. 2, the direction is alternately switched between the direction indicated by the dashed arrow and the opposite direction because it is an alternating magnetic field generated by an alternating current.

  FIG. 3 is a circuit diagram illustrating an example of a configuration of the image sensor 300 according to the first embodiment. The image sensor 300 illustrated in FIG. 3 includes an analog circuit 370 and a digital circuit 380. The analog circuit 370 has a pixel array 310, a vertical scanning circuit 302, and a peripheral circuit 303. The digital circuit 380 includes the signal processing circuit 304. Hereinafter, a case where the pixel array 310, the vertical scanning circuit 302, the peripheral circuit 303, and the signal processing circuit 304 are arranged in the same plane will be described as an example, but the present invention is not limited to this. A stacked structure in which the pixel array 310, the vertical scanning circuit 302, the peripheral circuit 303, and the signal processing circuit 304 are arranged on different surfaces different in the Z direction may be employed.

  The analog circuit 370 has an analog power supply wiring 320 and an analog ground wiring 330. The digital circuit 380 has a digital power supply wiring 340 and a digital ground wiring 350. Inside the image sensor 300, the analog power supply wiring 320 and the digital power supply wiring 340 are separated, and the analog ground wiring 330 and the digital ground wiring 350 are separated. Although not shown, when viewed in a direction perpendicular to the light receiving surface 301 of the image sensor 300, the analog power supply wiring 320 and the analog ground wiring 330 overlap, and the digital power supply wiring 340 and the digital ground wiring 350 overlap. The analog power supply wiring 320 is connected to the plurality of analog power supply electrodes 321. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. The digital power supply wiring 340 is connected to the plurality of digital power supply electrodes 341. The digital ground wiring 350 is connected to a plurality of digital ground electrodes 351. FIG. 3 shows only one analog power supply electrode 321, one analog ground electrode 331, one digital power supply electrode 341, and one digital ground electrode 351.

  The pixel array 310 includes a plurality of pixels 311 arranged in a two-dimensional matrix, that is, in a row direction and a column direction. The row direction is the horizontal direction in FIG. 3, that is, the horizontal direction. The column direction is the vertical direction in FIG. 3, that is, the vertical direction. Each pixel 311 outputs a pixel signal corresponding to the amount of received light as an analog signal. Each pixel 311 includes a photoelectric conversion unit and an amplification unit that outputs a signal based on charges generated by the photoelectric conversion unit. FIG. 3 shows a pixel array 310 of 2 rows × 4 columns for simplification of the drawing, but the number of rows and the number of columns of the pixel array 310 are not limited thereto.

  The vertical scanning circuit 302 performs drive control such as a reset operation, an accumulation operation, and a signal read operation of the pixels 311 on a row-by-row basis. The peripheral circuit 303 includes a differential amplifier circuit for removing noise such as random noise, and outputs a pixel signal from which noise has been removed as an analog signal. The signal processing circuit 304 processes the pixel signal and converts it into a digital signal under the control of the vertical scanning circuit 302 and the peripheral circuit 303, and outputs the digital signal from the signal electrode 361 to the wiring board 500 of FIG.

  FIG. 4 is a schematic plan view of the imaging unit 400 according to the first embodiment. FIG. 5 is a cross-sectional view of the imaging unit 400 along the line AA in FIG. FIG. 5 is a schematic diagram showing a cross section of the imaging unit 400 as viewed from the side. FIG. 5 schematically shows the ground wiring. The imaging unit 400 includes an imaging element 300, a wiring board 500, a frame 602, and a cover glass 603. The wiring board 500 is a printed wiring board in the first embodiment. Wiring board 500 has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  The wiring board 500 is a laminated board including a plurality of, for example, eight conductor layers 1 to 8 arranged at intervals in the Z direction which is the thickness direction of the wiring board 500. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1 to 8. A conductor pattern is arranged on each of the conductor layers 1 to 8. Wiring board 500 has two main surfaces 501 and 502. The image sensor 300 is mounted on the main surface 501 of the wiring board 500 on the conductor layer 1 side.

  The plurality of conductor layers 1 to 8 are laminated in the order of conductor layer 1, conductor layer 2, conductor layer 3, conductor layer 4, conductor layer 5, conductor layer 6, conductor layer 7, and conductor layer 8 from the image sensor 300 side. It is arranged. The conductor layers 1 and 8 are surface layers, that is, outer layers, and the conductor layers 2 to 7 are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502 on the conductor layer 8 side. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1 and 8.

  The imaging element 300 is arranged on the main surface 501 and is connected to the wiring board 500 by wire bonding. That is, the wiring of the imaging element 300 and the wiring of the wiring board 500 are electrically connected by the plurality of wires 610 as the plurality of metal members illustrated in FIG. The image sensor 300 is mounted on the wiring board 500 by wire bonding, but is not limited to this, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  Magnetic field noise generated from inductor elements such as the coils 104 and 203 in FIG. Assuming that the magnetic flux density is B, the area of the closed loop formed by the wiring is S, and the magnetic flux (magnetic field noise) interlinking the closed loop is Φ, Φ = B × S. That is, the magnetic flux Φ is proportional to the area S of the closed loop. When the magnetic flux Φ links the closed loop, an induced electromotive force V corresponding to the time change of the magnetic flux Φ is generated in the closed loop of the wiring. This follows Faraday-Lenz's law. The relationship between the induced electromotive force V and the change ΔΦ of the magnetic flux Φ during the minute time Δt is represented by V = −ΔΦ / Δt. Since ΔΦ is proportional to the area S of the closed loop, the induced electromotive force V generated in the closed loop is also proportional to the area S of the closed loop. According to Ohm's law, the relationship between the induced electromotive force V generated in the closed loop, the impedance R of the closed loop, and the induced current I flowing through the closed loop is represented by I = V / R. Since the induced current I is inversely proportional to the impedance R, the smaller the impedance R, the more easily the induced current I flows. When the magnetic flux Φ is in the opposite direction by 180 degrees, the directions of the induced electromotive force V and the current I are opposite. Further, even when the magnetic flux Φ arrives obliquely with respect to the closed loop plane, the induced electromotive force V is generated by the component of the magnetic flux Φ in the direction perpendicular to the loop surface.

  The closed loop in the imaging unit 400 has different resistance to magnetic field noise depending on the type of the connected circuit. Specifically, in the imaging unit 400, the closed loop of the ground of the analog circuit (hereinafter, also referred to as “analog ground”) is more sensitive to magnetic field noise than the closed loop of the ground of the digital circuit (hereinafter, also referred to as “digital ground”). Low resistance. In particular, the wiring related to the pixel array 310 has a low resistance to magnetic field noise because it directly affects the pixel signal. In addition, the lower the impedance of the wiring, the easier the induced current flows, and the lower the resistance to magnetic field noise. When a voltage distribution occurs in the closed loop of the analog ground due to the induced electromotive force, the pixel signal which is an analog signal fluctuates due to the distribution of the ground potential. The present inventors have found that in order to prevent pattern noise from occurring in the output image of the image sensor 300, that is, to increase the resistance of the image pickup unit 400 to magnetic field noise, the closed loop area of the analog ground should be reduced. Was.

  As shown in FIG. 3, the analog circuit 370 of the image sensor 300 includes a pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. The wiring board 500 of the imaging unit 400 according to the first embodiment has a ground wiring section 570 serving as a ground, as shown in FIG. The ground wiring section 570 includes a ground wiring 571 as a first ground wiring and a ground wiring 572 as a second ground wiring.

The ground wiring 571 is connected to the plurality of ground electrodes 531. 5, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 5 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among a plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. FIG 5, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400 is viewed from the side, that is, when the imaging unit 400 is viewed in the Y direction, a closed loop L1 of an analog ground is formed in the imaging unit 400, straddling the imaging element 300 and the wiring board 500. FIG. 5 shows the closed loop L1 by a two-dot chain line.

The closed loop L1 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571 of the wiring board 500. More specifically, the closed loop L1 includes an analog ground wiring 330, a pair of analog ground electrodes 331 ₁ and 331 ₂ , a pair of wires 611 ₁ and 611 ₂ , a pair of ground electrodes 531 ₁ and 531 ₂ , and a ground wiring 571. In.

  The ground wiring 572 is a part other than the ground wiring 571 when viewed in the Y direction, that is, a part that does not contribute to the formation of the closed loop L1 of the analog ground. For example, the ground wiring 572 includes a part that forms a closed loop of digital ground together with the digital ground wiring 350 (FIG. 3) of the image sensor 300 when viewed in the Y direction, and a part that does not contribute to the formation of any closed loop.

  Here, the area of the closed loop L1 of the analog ground when viewed in the Y direction, that is, the area of the portion surrounded by the two-dot chain line in FIG. 5 is defined as S1. The ground wiring 571 is disposed closer to the image sensor 300 than the center C1 of the wiring board 500 in the Z direction. The center C1 is the center between the two main surfaces 501 and 502, and is shown by a dashed line in FIG. Since the entire ground wiring 571 is disposed closer to the image sensor 300 than the center C1 in the Z direction of the wiring board 500, the area S1 of the closed loop L1 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L1 is proportional to the area S1 of the closed loop L1, the induced electromotive force generated in the closed loop L1 can be reduced by reducing the area S1. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  In the first embodiment, the ground wiring 571 includes only one conductor pattern 505 that is the first conductor pattern. The conductor pattern 505 is arranged on the conductor layer 1 which is a surface layer of the wiring board 500 on the side where the imaging element 300 is mounted. Since the conductor pattern 505 is arranged on the conductor layer 1, the area S1 of the closed loop L1 can be minimized, and the image generated by the imaging element 300 can be effectively suppressed from being disturbed. Image quality is further improved.

  The ground wiring 572 has a plurality of conductor patterns 506, which are a plurality of second conductor patterns, and a plurality of via conductors 508, which are a plurality of third via conductors. The conductor pattern 506 is arranged on the conductor layers 2 to 8. The plurality of conductor patterns 506 are electrically connected by the plurality of via conductors 508.

  FIG. 6A is a plan view of the first conductor layer of the wiring board 500 according to the first embodiment, that is, the conductor layer 1 which is the surface layer. FIG. 6B is a plan view of the second conductor layer of the wiring board 500 according to the first embodiment, that is, the conductor layer 2 that is the inner layer. As shown in FIG. 6A, a power supply electrode 521 electrically connected to the analog power supply electrode 321 of FIG. The power electrode 521 is a via conductor (not shown), and is electrically connected to a conductor pattern (not shown) disposed on any of the conductor layers 2 to 8.

  As shown in FIG. 6A, a ground electrode 531 electrically connected to the analog ground electrode 331 of FIG. 3 by wire bonding is disposed on the conductor layer 1. The ground electrode 531 is formed integrally with the conductor pattern 505.

  As shown in FIG. 6A, an electrode 541 that is electrically connected to the digital power supply electrode 341 or the signal electrode 361 of FIG. The electrode 541 is a via conductor (not shown), and is electrically connected to a conductor pattern (not shown) disposed on any of the conductor layers 2 to 8.

  As shown in FIG. 6A, a ground electrode 551 that is electrically connected to the digital ground electrode 351 of FIG. 3 by wire bonding is disposed on the conductor layer 1. The ground electrode 551 is a via conductor (not shown) and is electrically connected to the conductor pattern 506 of the ground wiring 572 disposed on any of the conductor layers 2 to 8. As shown in FIG. 6A, the conductor pattern 505 is a solid pattern having a quadrangular outer shape when viewed in the Z direction or a shape in which the square corners are R-shaped. As shown in FIG. 6B, the conductor pattern 506 is a solid pattern whose outer shape when viewed in the Z direction is a square shape or a shape in which a square corner is formed in an R shape.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the image sensor 300 be common, and the ground wiring 571 and the ground wiring 572 are electrically connected in the wiring board 500 of FIG. The ground wiring 571 is disposed closer to the image sensor 300 than the ground wiring 572. The ground wiring 571 and the ground wiring 572 are electrically connected by only one via conductor 511 that is a first via conductor arranged at one place so that the closed loop L1 of the analog ground does not extend to the ground wiring 572. ing. That is, the analog ground and the digital ground are connected only by the via conductor 511. In FIG. 5, the via conductors 511 are indicated by hatching different from the ground wirings 571 and 572.

  The ground line 571 is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572 is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. The ground wiring 571 and the ground wiring 572 are electrically connected only by the via conductor 511. Since the ground wiring 571 and the ground wiring 572 are electrically connected only by one via conductor 511, the closed loop L1 of the analog ground does not extend to the ground wiring 572, and the area S1 can be reduced. Accordingly, it is possible to suppress the image generated by the image sensor 300 from being disturbed, and the quality of the generated image is improved. By electrically connecting the digital ground wiring 350 of the image sensor 300 to the ground wiring 572, the voltage fluctuation of the analog signal can be made smaller than when the digital ground wiring 350 is electrically connected to the ground wiring 571. Accordingly, it is possible to suppress the image generated by the image sensor 300 from being disturbed, and the quality of the generated image is improved.

  In the first embodiment, the via conductor 511 is disposed so as to penetrate the conductor pattern 506 of the conductor layer 2 as shown in FIG. 6B, and as shown in FIG. The conductor pattern 506 of the conductor layer 3 is electrically connected.

  Note that the conductor pattern 505 of the conductor layer 1 and the conductor pattern 506 of the conductor layer 3 electrically connected by the via conductor 511 have the same structure as the planar antenna, and receive an external electromagnetic wave to change the potential in the wiring. May occur. In particular, when the via conductor 511 is located at the center or the end of the conductor pattern 505 of the conductor layer 1 and the conductor pattern 506 of the conductor layer 3 when viewed in the Z direction, the via conductor 511 is strongly affected by an electromagnetic wave of a specific frequency. Therefore, the via conductor 511 is at least the center and the end of the conductor pattern 505 of the conductor layer 1 when viewed in the Z direction, that is, in plan view, and in the first embodiment, the conductor pattern 505 of the conductor layer 1 and the conductor of the conductor layer 3. The pattern 506 is arranged so as to avoid the center and the end. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

[Second embodiment]
An imaging unit according to the second embodiment will be described. In the first embodiment, the case where the wiring board on which the semiconductor element is mounted is a printed wiring board has been described. In the second embodiment, the case where the wiring board on which the semiconductor element is mounted is a ceramic package will be described. FIG. 7 is a cross-sectional view of an imaging unit 400A according to the second embodiment. FIG. 7 is a schematic diagram illustrating a side view of a cross section of the imaging unit 400A at a position corresponding to the line AA illustrated in FIG. Note that, in the imaging unit 400A of the second embodiment, the same components as those of the imaging unit 400 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 7, the imaging unit 400A includes the imaging element 300, a wiring board 500A, and a cover glass 603. Wiring board 500A is a ceramic package having a frame to which cover glass 603 is attached. Wiring board 500A has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electric insulation, for example, ceramic.

  Wiring board 500A is a laminated substrate including a plurality of, for example, five conductor layers 1A, 2A, 3A, 4A, and 5A, which are arranged at intervals in the Z direction that is the thickness direction of wiring board 500A. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1A to 5A. A conductor pattern is arranged on each of the conductor layers 1A to 5A. Wiring board 500A has two main surfaces 501A and 502A. The imaging element 300 is mounted on the main surface 501A on the side of the conductor layer 1A in the wiring board 500A.

  The plurality of conductor layers 1A to 5A are arranged in the order of the conductor layer 1A, the conductor layer 2A, the conductor layer 3A, the conductor layer 4A, and the conductor layer 5A from the image sensor 300 side. The conductor layers 1A and 5A are surface layers, that is, outer layers, and the conductor layers 2A to 4A are inner layers. The number of conductor layers is not limited to five, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more.

  The image sensor 300 is arranged on the main surface 501A and connected to the wiring board 500A by wire bonding. The image pickup device 300 is mounted on the wiring board 500A by wire bonding, but is not limited to this, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes the pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. As shown in FIG. 7, the wiring board 500A has a ground wiring section 570A serving as a ground. The ground wiring section 570A includes a ground wiring 571A as a first ground wiring and a ground wiring 572A as a second ground wiring.

The ground wiring 571A is connected to a plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1A. 7, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 7 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. 7, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400A is viewed from the side, that is, when the imaging unit 400A is viewed in the Y direction, a closed loop L2 of an analog ground is formed in the imaging unit 400A, straddling the imaging element 300 and the wiring board 500A. FIG. 7 shows the closed loop L2 by a two-dot chain line.

The closed loop L2 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571A of the wiring board 500A. More specifically, the closed loop L2 includes an analog ground wire 330, a pair of analog ground electrodes 331 ₁ and 331 ₂ , a pair of wires 611 ₁ and 611 ₂ , a pair of ground electrodes 531 ₁ and 531 ₂ , and a ground wire 571A. In.

  The ground wiring 572A is a part other than the ground wiring 571A when viewed in the Y direction, that is, a part that does not contribute to the formation of the closed loop L2 of the analog ground. For example, the ground wiring 572A includes a part that forms a closed loop of digital ground together with the digital ground wiring 350 (FIG. 3) of the image sensor 300 when viewed in the Y direction, and a part that does not contribute to the formation of any closed loop.

  Here, the area of the closed loop L2 of the analog ground when viewed in the Y direction, that is, the area of the portion surrounded by the two-dot chain line in FIG. 7 is defined as S2. The ground wiring 571A is disposed closer to the image sensor 300 than the center C2 of the wiring board 500A in the Z direction. The center C2 is a center between the two main surfaces 501A and 502A, and is shown by a dashed line in FIG. Since the entire ground wiring 571A is disposed closer to the image sensor 300 than the center C2 in the Z direction of the wiring board 500A, the area S2 of the closed loop L2 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L2 is proportional to the area S2 of the closed loop L2, the induced electromotive force generated in the closed loop L2 can be reduced by reducing the area S2. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

The ground wiring 571A includes one conductor pattern 505A that is the first conductor pattern. The conductor pattern 505A is arranged on the conductor layer 2A. Further, the ground line 571A includes a via conductor 513A ₁ for connecting the ground electrode 531 ₁ and the conductor pattern 505A, the via conductors 513A ₂ for connecting the ground electrode 531 ₂ and the conductor pattern 505A, the. The ground wiring 572A includes a plurality of conductor patterns 506A, which are a plurality of second conductor patterns, spaced apart from each other, and a plurality of via conductors 508A, which are a plurality of third via conductors. The conductor pattern 506A is arranged on the conductor layers 3A to 5A. The plurality of conductor patterns 506A are electrically connected by the plurality of via conductors 508A.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the imaging element 300 be common, and the ground wiring 571A and the ground wiring 572A are electrically connected on the wiring board 500A. The ground wiring 571A is arranged closer to the image sensor 300 than the ground wiring 572A. The ground wiring 571A and the ground wiring 572A are electrically connected by only one via conductor 511A which is a first via conductor arranged at one place so that the closed loop L2 of the analog ground does not spread to the ground wiring 572A. I have. That is, the analog ground and the digital ground are connected only by the via conductor 511A. In FIG. 7, the via conductor 511A is indicated by hatching different from the ground wirings 571A and 572A.

  The ground line 571A is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572A is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. The ground wiring 571A and the ground wiring 572A are electrically connected by only one via conductor 511A. Since the ground wiring 571A and the ground wiring 572A are electrically connected only by one via conductor 511A, the closed loop L2 of the analog ground does not extend to the ground wiring 572A, and the area S2 can be reduced. Accordingly, it is possible to suppress the image generated by the image sensor 300 from being disturbed, and the quality of the generated image is improved.

  In the second embodiment, the via conductor 511A is arranged to penetrate the conductor pattern 506A of the conductor layer 3A, and electrically connects the conductor pattern 505A of the conductor layer 2A and the conductor pattern 506A of the conductor layer 4A. .

  The via conductor 511A is at least the center and the end of the conductor pattern 505A of the conductor layer 2A when viewed in the Z direction, that is, in plan view, and in the second embodiment, the conductor pattern 505A of the conductor layer 2A and the conductor pattern 506A of the conductor layer 4A. Are arranged so as to avoid the center and the end. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

[Third embodiment]
An imaging unit according to the third embodiment will be described. FIG. 8 is a cross-sectional view of an imaging unit 400B according to the third embodiment. FIG. 8 is a schematic diagram illustrating a side view of a cross section of the imaging unit 400B at a position corresponding to line AA illustrated in FIG. Note that, in the imaging unit 400B of the third embodiment, the same components as those of the imaging unit 400 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  As shown in FIG. 8, the imaging unit 400B includes an imaging element 300, a wiring board 500B, a frame 602, and a cover glass 603. The wiring board 500B is a printed wiring board in the third embodiment. Wiring board 500B has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  The wiring board 500B is a laminated board including a plurality of, for example, eight conductor layers 1B to 8B arranged at intervals in the Z direction which is the thickness direction of the wiring board 500B. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1B to 8B. A conductor pattern is arranged on each of the conductor layers 1B to 8B. Wiring board 500B has two main surfaces 501B and 502B. The imaging element 300 is mounted on the main surface 501B of the wiring board 500B on the side of the conductor layer 1B.

  The plurality of conductor layers 1B to 8B are laminated in the order of the conductor layer 1B, the conductor layer 2B, the conductor layer 3B, the conductor layer 4B, the conductor layer 5B, the conductor layer 6B, the conductor layer 7B, and the conductor layer 8B from the imaging element 300 side. It is arranged. The conductor layers 1B and 8B are surface layers, that is, outer layers, and the conductor layers 2B to 7B are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502B on the side of the conductor layer 8B. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1B and 8B.

  The image sensor 300 is arranged on the main surface 501B and connected to the wiring board 500B by wire bonding. The image sensor 300 is mounted on the wiring board 500B by wire bonding, but is not limited to this, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes the pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. As shown in FIG. 8, the wiring board 500B has a ground wiring portion 570B serving as a ground. The ground wiring section 570B includes a ground wiring 571B as a first ground wiring and a ground wiring 572B as a second ground wiring.

The ground wiring 571B is connected to a plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1B. 8, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 8 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. 8, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400B is viewed from the side, that is, when the imaging unit 400B is viewed in the Y direction, a closed loop L3 of an analog ground is formed in the imaging unit 400B, straddling the imaging element 300 and the wiring board 500B. FIG. 8 shows the closed loop L3 by a two-dot chain line.

The closed loop L3 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571B of the wiring board 500B. More specifically, the closed loop L3 includes an analog ground wire 330, a pair of analog ground electrodes 331 ₁ and 331 ₂ , a pair of wires 611 ₁ and 611 ₂ , a pair of ground electrodes 531 ₁ and 531 ₂ , and a ground wire 571B. In.

  The ground wiring 572B is a part other than the ground wiring 571B when viewed in the Y direction, that is, a part that does not contribute to the formation of the closed loop L3 of the analog ground. For example, the ground wiring 572B includes a part that forms a closed loop of digital ground together with the digital ground wiring 350 (FIG. 3) of the image sensor 300 when viewed in the Y direction, and a part that does not contribute to the formation of any closed loop.

  Here, the area of the closed loop L3 of the analog ground when viewed in the Y direction, that is, the area of the portion surrounded by the two-dot chain line in FIG. 8 is defined as S3. The ground wiring 571B is arranged closer to the image sensor 300 than the center C3 in the Z direction of the wiring board 500B. The center C3 is the center between the two main surfaces 501B and 502B, and is shown by a dashed line in FIG. Since the entire ground wiring 571B is disposed closer to the image sensor 300 than the center C3 in the Z direction of the wiring board 500B, the area S3 of the closed loop L3 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L3 is proportional to the area S3 of the closed loop L3, the induced electromotive force generated in the closed loop L3 can be reduced by reducing the area S3. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  The ground wiring 571B includes only one conductor pattern 505B that is the first conductor pattern. The conductor pattern 505B is arranged on the conductor layer 1B, which is the surface layer on the side on which the imaging element 300 is mounted on the wiring board 500B. The ground electrode 531 is formed integrally with the conductor pattern 505B. Since the conductor pattern 505B is arranged on the conductor layer 1B, the area S3 of the closed loop L3 can be minimized, and the image generated by the image sensor 300 can be effectively suppressed from being disturbed. Image quality is further improved.

  The ground wiring 572B includes a plurality of conductor patterns 506B, which are a plurality of second conductor patterns, and a plurality of via conductors 508B, which are a plurality of third via conductors. The conductor pattern 506B is arranged on the conductor layers 1B to 8B. The plurality of conductor patterns 506B are electrically connected by the plurality of via conductors 508B. The conductor pattern 506B of the conductor layer 1B is arranged at a position not included in the closed loop L3, that is, at a position not in contact with the conductor pattern 505B. That is, in the conductor layer 1B, the conductor pattern 505B and the conductor pattern 506B are arranged apart from each other. The conductor pattern 506B of the conductor layer 1B may be formed integrally with a ground electrode (not shown) connected to the digital ground electrode 351 shown in FIG. 3 by wire bonding.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the imaging element 300 be common, and the ground wiring 571B and the ground wiring 572B are electrically connected on the wiring board 500B. The ground wiring 571B and the ground wiring 572B are electrically connected to each other by only one via conductor 511B, which is a first via conductor arranged at one place, so that the closed loop of the analog ground does not extend to the ground wiring 572B. I have. That is, the analog ground and the digital ground are connected only by the via conductor 511B. In FIG. 8, the via conductor 511B is indicated by hatching different from the ground wirings 571B and 572B.

  The ground line 571B is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572B is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. The ground wiring 571B and the ground wiring 572B are electrically connected by only one via conductor 511B. Since the ground wiring 571B and the ground wiring 572B are electrically connected by only one via conductor 511B, the closed loop L3 of the analog ground does not extend to the ground wiring 572B, and the area S3 can be reduced. Accordingly, it is possible to suppress the image generated by the image sensor 300 from being disturbed, and the quality of the generated image is improved.

  In the third embodiment, the via conductor 511B is arranged to penetrate the conductor pattern 506B of the conductor layer 2B, and electrically connects the conductor pattern 505B of the conductor layer 1B and the conductor pattern 506B of the conductor layer 3B. .

  The via conductor 511B is at least the center and the end of the conductor pattern 505B of the conductor layer 1B when viewed in the Z direction, and in the third embodiment, the center and the end of the conductor pattern 505B of the conductor layer 1B and the conductor pattern 506B of the conductor layer 3B. It is arranged to avoid. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

[Fourth embodiment]
An imaging unit according to the fourth embodiment will be described. FIG. 9 is a sectional view of an imaging unit 400C according to the fourth embodiment. FIG. 9 is a schematic diagram showing a side view of a cross section of the imaging unit 400C at a position corresponding to line AA shown in FIG. Note that, in the imaging unit 400C of the fourth embodiment, the same components as those of the imaging unit 400 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  As illustrated in FIG. 9, the imaging unit 400C includes an imaging element 300, a wiring board 500C, a frame 602, and a cover glass 603. The wiring board 500C is a printed wiring board in the fourth embodiment. Wiring board 500C has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  The wiring board 500C is a laminated substrate including a plurality of, for example, eight conductor layers 1C to 8C arranged at intervals in the Z direction which is the thickness direction of the wiring board 500C. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1C to 8C. A conductor pattern is arranged on each of the conductor layers 1C to 8C. Wiring board 500C has two main surfaces 501C and 502C. The imaging element 300 is mounted on the main surface 501C of the wiring board 500C on the side of the conductor layer 1C.

  The plurality of conductor layers 1C to 8C are laminated in the order of the conductor layer 1C, the conductor layer 2C, the conductor layer 3C, the conductor layer 4C, the conductor layer 5C, the conductor layer 6C, the conductor layer 7C, and the conductor layer 8C from the imaging element 300 side. It is arranged. The conductor layers 1C and 8C are surface layers, that is, outer layers, and the conductor layers 2C to 7C are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502C on the side of the conductor layer 8C. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1C and 8C.

  The image sensor 300 is arranged on the main surface 501C and is connected to the wiring board 500C by wire bonding. The image sensor 300 is mounted on the wiring board 500C by wire bonding, but is not limited to this, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes the pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. As shown in FIG. 9, the wiring board 500C has a ground wiring portion 570C serving as a ground. The ground wiring section 570C includes a ground wiring 571C that is a first ground wiring and a ground wiring 572C that is a second ground wiring.

The ground wiring 571C is connected to the plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1C. 9, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 9 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. 9 shows, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400C is viewed from the side, that is, when the imaging unit 400C is viewed in the Y direction, a closed loop L4 of an analog ground is formed in the imaging unit 400C, straddling the imaging element 300 and the wiring board 500C. FIG. 9 shows the closed loop L4 by a two-dot chain line.

The closed loop L4 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571C of the wiring board 500C. More specifically, the closed loop L4 connects the analog ground line 330, the pair of analog ground electrodes 331 ₁ and 331 ₂ , the pair of wires 611 ₁ and 611 ₂ , the pair of ground electrodes 531 ₁ and 531 ₂ , and the ground line 571C. Contains.

  The ground wiring 572C is a part other than the ground wiring 571C when viewed in the Y direction, that is, a part that does not contribute to the formation of the closed loop L4 of the analog ground. For example, the ground wiring 572C includes a part that forms a closed loop of digital ground together with the digital ground wiring 350 (FIG. 3) of the image sensor 300 when viewed in the Y direction, and a part that does not contribute to the formation of any closed loop.

  The area of the closed loop L4 of the analog ground when viewed in the Y direction, that is, the area of the portion surrounded by the two-dot chain line in FIG. 9 is defined as S4. The ground wiring 571C is disposed closer to the image sensor 300 than the center C4 of the wiring board 500C in the Z direction. The center C4 is the center between the two main surfaces 501C and 502C, and is shown by a dashed line in FIG. Since the entire ground wiring 571C is disposed closer to the image sensor 300 than the center C4 of the wiring board 500C in the Z direction, the area S4 of the closed loop L4 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L4 is proportional to the area S4 of the closed loop L4, the induced electromotive force generated in the closed loop L4 can be reduced by reducing the area S4. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  In the fourth embodiment, the ground wiring 571C is composed of a plurality of conductor patterns 505C, which are a plurality of first conductor patterns arranged at intervals, and a plurality of second via conductors connecting the plurality of conductor patterns 505C. And a plurality of via conductors 513C. FIG. 9 illustrates three conductor patterns 505C as the plurality of conductor patterns 505C. At least one of the plurality of conductor patterns 505C is disposed on the conductor layer 1C, which is the surface layer on the side on which the imaging element 300 is mounted on the wiring board 500C. The ground electrode 531 is formed integrally with the conductor pattern 505C of the conductor layer 1C. The remaining two conductor patterns 505C are arranged on the conductor layers 2C and 3C. Since the plurality of conductor patterns 505C are connected by the plurality of via conductors 513C, at a frequency in the kHz band, that is, at a frequency of 1 [kHz] or more and less than 1 [MHz], the induced current is applied to the entirety of the plurality of conductor patterns 505C. Flows. Thereby, the fluctuation of the ground potential of the analog ground can be effectively suppressed, and the occurrence of pattern noise, that is, the disturbance of the image generated by the image sensor 300 can be effectively suppressed, and the generated image can be effectively controlled. Quality is further improved.

As shown in FIG. 9, the closed loop L4 is the largest closed loop among analog ground closed loops. Therefore, when viewed in the Y direction, the closed loop L4 includes a part of the conductor pattern 505C of the conductor layer 1C and a part of the conductor pattern 505C of the conductor layer 3C in the ground wiring 571C. When viewed in the Y direction, the closed loop L4 is formed by two via conductors 513C ₁ , 513C that are the most separated among the plurality of via conductors 513C that connect the conductor pattern 505C of the conductor layer 1C and the conductor pattern 505C of the conductor layer 3C. ₂ inclusive.

  The ground wiring 572C has a plurality of conductor patterns 506C, which are a plurality of second conductor patterns, spaced apart from each other, and a plurality of via conductors 508C, which are a plurality of third via conductors. The conductor pattern 506C is arranged on the conductor layers 4C to 8C. The plurality of conductor patterns 506C are electrically connected by the plurality of via conductors 508C.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the imaging element 300 be shared, and the ground wiring 571C and the ground wiring 572C are electrically connected on the wiring board 500C. The ground wiring 571C is disposed closer to the image sensor 300 than the ground wiring 572C. The ground wiring 571C and the ground wiring 572C are electrically connected by only one via conductor 511C that is a first via conductor arranged at one place so that the closed loop of the analog ground does not spread to the ground wiring 572C. I have. That is, the analog ground and the digital ground are connected only by the via conductor 511C. In FIG. 9, the via conductor 511C is indicated by hatching different from the ground wirings 571C and 572C.

  The ground line 571C is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572C is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. The ground wiring 571C and the ground wiring 572C are electrically connected by only one via conductor 511C. Since the ground wiring 571C and the ground wiring 572C are electrically connected only by one via conductor 511C, the closed loop L4 of the analog ground does not extend to the ground wiring 572C, and the area S4 can be reduced. Accordingly, it is possible to suppress the image generated by the image sensor 300 from being disturbed, and the quality of the generated image is improved.

  In the fourth embodiment, the via conductor 511C is disposed to penetrate the conductor pattern 506C of the conductor layer 4C, and electrically connects the conductor pattern 505C of the conductor layer 3C and the conductor pattern 506C of the conductor layer 5C. .

  The via conductor 511C is at least the center and the end of the conductor pattern 505C of the conductor layer 3C when viewed in the Z direction, and in the fourth embodiment, the center and the end of the conductor pattern 505C of the conductor layer 3C and the conductor pattern 506C of the conductor layer 5C. It is arranged to avoid. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

[Fifth Embodiment]
An imaging unit according to the fifth embodiment will be described. In the first to fourth embodiments, the case where the first ground wiring and the second ground wiring are connected by only one first via conductor has been described. In the fifth embodiment, a case where the first ground wiring and the second ground wiring are connected by only a plurality of first via conductors will be described. FIG. 10 is a sectional view of an imaging unit 400D according to the fifth embodiment. FIG. 11A is a plan view of a second conductor layer of the wiring board according to the fifth embodiment. FIG. 11B is a schematic view of the image sensor 300 as viewed in plan. FIG. 10 is a schematic view of a cross section of the imaging unit 400D taken along the line AA shown in FIG. Note that, in the imaging unit 400D of the fifth embodiment, the same components as those of the imaging unit 400 of the first embodiment are given the same reference numerals, and description thereof will be omitted.

  As illustrated in FIG. 10, the imaging unit 400D includes an imaging element 300, a wiring board 500D, a frame 602, and a cover glass 603. The wiring board 500D is a printed wiring board in the fifth embodiment. Wiring board 500D has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  The wiring board 500D is a laminated substrate including a plurality of, for example, eight conductor layers 1D to 8D arranged at intervals in the Z direction which is the thickness direction of the wiring board 500D. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1D to 8D. A conductor pattern is arranged on each of the conductor layers 1D to 8D. Wiring board 500D has two main surfaces 501D and 502D. The imaging element 300 is mounted on the main surface 501D of the wiring board 500D on the side of the conductor layer 1D.

  The plurality of conductor layers 1D to 8D are stacked in the order of the conductor layer 1D, the conductor layer 2D, the conductor layer 3D, the conductor layer 4D, the conductor layer 5D, the conductor layer 6D, the conductor layer 7D, and the conductor layer 8D from the imaging element 300 side. It is arranged. The conductor layers 1D and 8D are surface layers, that is, outer layers, and the conductor layers 2D to 7D are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502D on the conductor layer 8D side. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1D and 8D.

  The image sensor 300 is arranged on the main surface 501D and is connected to the wiring board 500D by wire bonding. In addition, the imaging element 300 is mounted on the wiring board 500D by wire bonding, but is not limited to this, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes the pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. As shown in FIG. 10, the wiring board 500D has a ground wiring part 570D serving as a ground. The ground wiring section 570D includes a ground wiring 571D as a first ground wiring and a ground wiring 572D as a second ground wiring.

The ground wiring 571D is connected to a plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1D. 10, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 10 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. 10, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400D is viewed from the side, that is, when the imaging unit 400D is viewed in the Y direction, a closed loop L51 of an analog ground is formed in the imaging unit 400D, straddling the imaging element 300 and the wiring board 500D. FIG. 10 shows the closed loop L51 by a two-dot chain line.

The closed loop L51 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571D of the wiring board 500D. More specifically, the closed loop L51 includes an analog ground wiring 330, a pair of analog ground electrodes 331 ₁ and 331 ₂ , a pair of wires 611 ₁ and 611 ₂ , a pair of ground electrodes 531 ₁ and 531 ₂ , and a ground wiring 571D. In.

  The area of the closed loop L51 of the analog ground when viewed in the Y direction is defined as S51. The ground wiring 571D is arranged closer to the image sensor 300 than the center C5 in the Z direction of the wiring board 500D. The center C5 is the center between the two main surfaces 501D and 502D, and is shown by a dashed line in FIG. Since the entire ground wiring 571D is arranged closer to the image sensor 300 than the center C5 in the Z direction of the wiring board 500D, the area S51 of the closed loop L51 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L51 is proportional to the area S51 of the closed loop L51, the induced electromotive force generated in the closed loop L51 can be reduced by reducing the area S51. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  In the fifth embodiment, the ground wiring 571D is composed of only one conductor pattern 505D that is the first conductor pattern. The conductor pattern 505D is arranged on the conductor layer 1D, which is the surface layer on the side on which the imaging element 300 is mounted on the wiring board 500D. The ground electrode 531 is formed integrally with the conductor pattern 505D. Since the conductor pattern 505D is arranged on the conductor layer 1D, the area S51 of the closed loop L51 can be made as small as possible, and the image generated by the imaging element 300 can be effectively suppressed from being disturbed. Image quality is further improved.

  The ground wiring 572D has a plurality of conductor patterns 506D, which are a plurality of second conductor patterns, and a plurality of via conductors 508D, which are a plurality of third via conductors. The conductor pattern 506D is arranged on the conductor layers 2D to 8D. The plurality of conductor patterns 506D are electrically connected by the plurality of via conductors 508D.

It is preferable that the ground of the analog circuit and the ground of the digital circuit of the imaging element 300 be common, and the ground wiring 571D and the ground wiring 572D are electrically connected to each other on the wiring board 500D. The ground wiring 571D is arranged closer to the image sensor 300 than the ground wiring 572D. The ground wiring 571D and the ground wiring 572D are electrically connected to each other only by a plurality of via conductors 511D, which are a plurality of first via conductors arranged at intervals. In the fifth embodiment, a plurality of via conductors 511D is composed of two via conductors 511D _1, 511D _2. In FIG. 10, the via conductor 511D is indicated by hatching different from the ground wirings 571D and 572D.

  The ground line 571D is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572D is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. The ground wiring 571D and the ground wiring 572D are electrically connected only by the plurality of via conductors 511D. As described above, the ground of the analog circuit and the ground of the digital circuit of the image sensor 300 are shared by the wiring board 500D.

Here, the ground wiring 571D and the ground wiring 572D are connected by the plurality of via conductors 511D, thereby forming a closed loop L52 that partially overlaps the closed loop L51 when viewed in the Y direction. In FIG. 10, the closed loop L52 is indicated by a dotted line. The closed loop L52 includes an analog ground wire 330, a pair of analog ground electrodes 331 ₁ and 331 ₂ , a pair of wires 611 ₁ and 611 ₂ , a pair of ground electrodes 531 ₁ and 531 ₂ , and a ground wire 571D. Further, the closed loop L52 includes two via conductors 511D ₁ and 511D ₂ which are the most distant from the plurality of via conductors 511D, and a ground wiring 572D. That is, the closed loop L52 is a closed loop larger than the closed loop L51 in which the closed loop L51 and the closed loop L50 formed on the ground wiring 572D are connected by the plurality of via conductors 511D.

The present inventors consider that even if the number of via conductors 511D is plural, if the interval between the plurality of via conductors 511D is narrow, the formed closed loop is divided into a closed loop L51 and a closed loop L50. I found that I can do it. Here, the distance between the two furthest via conductors 511D ₁ and 511D ₂ among the plurality of via conductors 511D is D1. The distance D1, as shown in FIG. 11 (a), and a portion opposite to the side facing the via conductors 511D ₂ in the via conductors 511D _1, the side facing the via conductors 511D ₁ in via conductors 511D ₂ is It is the linear distance to the opposite part.

As the distance D1 is narrow, the impedance of the portion between the via conductors 511D _1, 511D ₂ in the conductive pattern 505D is reduced. Impedance of this portion, as the distance D1 is narrow, and the impedance of the via conductors 511D _1, 511D _2, relatively smaller than the sum of the impedance of the impedance of the portion of the closed loop L50 formed in the ground wiring 572d. Therefore, it can be considered that most of the induced current that loops through the analog ground wiring 330 flows through the closed loop L51. Conversely, the impedance of the portion between the via conductors 511D ₁ and 511D _{2 in} the conductor pattern 505D increases as the distance D1 increases. The impedance of this portion approaches the total impedance of the via conductors 511D ₁ and 511D _{2 and} the impedance of the portion of the closed loop L50 formed on the ground wiring 572D as the distance D1 is wide. This makes it easier for the induced current to shunt in the via conductors 511D ₁ and 511D ₂ .

第５実施形態では、複数のヴィア導体５１１Ｄが、図１１（ａ）に示すように２つのヴィア導体５１１Ｄ_１，５１１Ｄ_２のみであるため、この２つのヴィア導体５１１Ｄ_１，５１１Ｄ_２の距離Ｄ１が、上記の式を満たせばよい。 As shown in FIG. 11B, when viewed in the Z direction, the outer shape of the image sensor 300 is rectangular. When the image sensor 300 is viewed in the Z direction, that is, when viewed in a plan view, the length of the long side 300X that is the first side of the image sensor 300 is X1, and the length of the short side 300Y that is the second side intersecting the long side. Let Y1 be the length. The present inventors have found that, among the plurality of via conductors 511D, the distance D1 between the _two via conductors 511D ₁ and 511D _{2 that} are the most distant from each other only needs to be arranged so as to satisfy the following expression.

In the fifth embodiment, since the plurality of via conductors 511D are only two via conductors 511D ₁ and 511D ₂ as shown in FIG. 11A, the distance D1 between the _two via conductors 511D ₁ and 511D ₂ is smaller. , The above equation may be satisfied.

  If the distance D1 satisfies the above expression, the plurality of via conductors 511D are arranged in a narrow range. Since the plurality of via conductors 511D are arranged in a narrow range, the induced current flowing through the closed loop L52 is much smaller than the induced current flowing through the closed loop L51, even if an apparently larger closed loop L52 than the closed loop L51 is formed. . Therefore, since the plurality of via conductors 511D are arranged in a narrow range, the closed loop of the analog ground can be regarded as a closed loop L51.

Further, if the distance D1 satisfies the following expression, the plurality of via conductors 511D are arranged in a narrower range, and thus it is more preferable.

  As described above, according to the fifth embodiment, as shown in FIG. 10, since the entire ground wiring 571D is disposed closer to the image sensor 300 than the center C5, the area of the closed loop L51 can be reduced. By reducing the area of the closed loop L51, the potential fluctuation of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

Here, among the plurality of via conductors 508D in the ground wiring 572D, the distance between the two via conductors 508D ₁ and 508D ₂ which are the most separated is D3. Distance D3 is the side facing the via conductors 508D ₂ in via conductors 508D ₁ is a linear distance between the opposite side portions and opposite side portions, the side facing the via conductors 508D ₁ in via conductors 508D ₂ . In the fifth embodiment, the distance D1 is smaller than the distance D3. This causes the plurality of via conductors 511D to be arranged in a narrow range, so that the induced current flows more easily in the closed loop L51 than in the closed loop L52. Therefore, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  In the fifth embodiment, the via conductor 511D is arranged to penetrate the conductor pattern 506D of the conductor layer 2D, and electrically connects the conductor pattern 505D of the conductor layer 1D and the conductor pattern 506D of the conductor layer 3D. . Therefore, in the fifth embodiment, as in the first to fourth embodiments, each via conductor 511D has at least one of the conductor pattern 505D of the conductor layer 2D and the conductor pattern 506D of the conductor layer 3D when viewed in the Z direction. May be arranged so as to avoid the center and the end. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

[Sixth embodiment]
An imaging unit according to the sixth embodiment will be described. FIG. 12 is a sectional view of an imaging unit 400H according to the sixth embodiment. FIG. 12 is a schematic diagram illustrating a cross-sectional side view of the imaging unit 400H at a position corresponding to line AA illustrated in FIG. Note that, in the imaging unit 400H of the sixth embodiment, the same components as those of the imaging unit 400 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  As shown in FIG. 12, the imaging unit 400H includes an imaging element 300, a wiring board 500H, a frame 602, and a cover glass 603. The wiring board 500H is a printed wiring board in the sixth embodiment. Wiring board 500H has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  Wiring board 500H is a laminated substrate including a plurality of, for example, eight conductor layers 1H to 8H arranged at intervals in the Z direction which is the thickness direction of wiring board 500H. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1H to 8H. A conductor pattern is arranged on each of the conductor layers 1H to 8H. Wiring board 500H has two main surfaces 501H and 502H. The imaging element 300 is mounted on the main surface 501H of the wiring board 500H on the conductor layer 1H side.

  The plurality of conductor layers 1H to 8H are laminated in the order of the conductor layer 1H, the conductor layer 2H, the conductor layer 3H, the conductor layer 4H, the conductor layer 5H, the conductor layer 6H, the conductor layer 7H, and the conductor layer 8H from the imaging element 300 side. It is arranged. The conductor layers 1H and 8H are surface layers, that is, outer layers, and the conductor layers 2H to 7H are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502H on the conductor layer 8H side. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1H and 8H.

  The image sensor 300 is arranged on the main surface 501H and is connected to the wiring board 500H by wire bonding. The image sensor 300 is mounted on the wiring board 500H by wire bonding, but is not limited thereto, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes the pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. As shown in FIG. 12, the wiring board 500H has a ground wiring portion 570H serving as a ground. The ground wiring section 570H includes a ground wiring 571H as a first ground wiring and a ground wiring 572H as a second ground wiring.

The ground wiring 571H is connected to the plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1H. 12, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 12 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. The 12, of the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400H is viewed from the side, that is, when the imaging unit 400H is viewed in the Y direction, a closed loop L9 of an analog ground is formed in the imaging unit 400H, straddling the imaging element 300 and the wiring board 500H. FIG. 12 shows the closed loop L9 by a two-dot chain line.

The closed loop L9 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571H of the wiring board 500H. More specifically, the closed loop L9 connects the analog ground wiring 330, the pair of analog ground electrodes 331 ₁ and 331 ₂ , the pair of wires 611 ₁ and 611 ₂ , the pair of ground electrodes 531 ₁ and 531 ₂ , and the ground wiring 571H. Contains.

  The area of the closed loop L9 of the analog ground when viewed in the Y direction, that is, the area of the portion surrounded by the two-dot chain line in FIG. 12 is defined as S9. The ground wiring 571H is disposed closer to the image sensor 300 than the center C9 in the Z direction of the wiring board 500H. The center C9 is a center between the two main surfaces 501H and 502H, and is shown by a dashed line in FIG. Since the entire ground wiring 571H is disposed closer to the image sensor 300 than the center C9 in the Z direction of the wiring board 500H, the area S9 of the closed loop L9 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L9 is proportional to the area S9 of the closed loop L9, the induced electromotive force generated in the closed loop L9 can be reduced by reducing the area S9. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  In the sixth embodiment, the ground wiring 571H is composed of a plurality of conductor patterns 505H, which are a plurality of first conductor patterns arranged at intervals from each other, and a plurality of second via conductors connecting the plurality of conductor patterns 505H. And a plurality of via conductors 513H. FIG. 12 illustrates three conductor patterns 505H. At least one of the plurality of conductor patterns 505H is arranged on the conductor layer 1H, which is the surface layer on the side on which the image sensor 300 is mounted on the wiring board 500H. The remaining two conductor patterns 505H are arranged on the conductor layers 2H and 3H. Since the plurality of conductor patterns 505H are connected by the plurality of via conductors 513H, at a frequency in the kHz band, that is, at a frequency equal to or higher than 1 [kHz] and lower than 1 [MHz], the induced current is applied to the entire plurality of conductor patterns 505H. Flows. Thereby, the fluctuation of the ground potential of the analog ground can be effectively suppressed, and the occurrence of pattern noise, that is, the disturbance of the image generated by the image sensor 300 can be effectively suppressed, and the generated image can be effectively controlled. Quality is further improved.

As shown in FIG. 12, the closed loop L9 is the largest closed loop among analog ground closed loops. Therefore, when viewed in the Y direction, the closed loop L9 includes a part of the conductor pattern 505H of the conductor layer 1H and a part of the conductor pattern 505H of the conductor layer 3H in the ground wiring 571H. Further, when viewed in the Y direction, the closed loop L9 is formed by two via conductors 513H ₁ , 513H that are the most separated among the plurality of via conductors 513H that connect the conductor pattern 505H of the conductor layer 1H and the conductor pattern 505H of the conductor layer 3H. ₂ inclusive.

  The ground wiring 572H includes a plurality of conductor patterns 506H, which are a plurality of second conductor patterns, spaced apart from each other, and a plurality of via conductors 508H, which are a plurality of third via conductors. The conductor pattern 506H is arranged on the conductor layers 4H to 8H. The plurality of conductor patterns 506H are electrically connected by the plurality of via conductors 508H.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the imaging element 300 be common, and the ground wiring 571H and the ground wiring 572H are electrically connected on the wiring board 500H. The ground wiring 571H is arranged closer to the image sensor 300 than the ground wiring 572H. In the sixth embodiment, the ground wiring 571H and the ground wiring 572H are electrically connected only by the plurality of via conductors 511H, which are the plurality of first via conductors. That is, the analog ground and the digital ground are connected only by the plurality of via conductors 511H. In FIG. 12, the via conductor 511H is indicated by hatching different from the ground wirings 571H and 572H.

  The ground line 571H is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572H is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. The ground wiring 571H and the ground wiring 572H are electrically connected only by the plurality of via conductors 511H. As described above, the ground of the analog circuit and the ground of the digital circuit of the image sensor 300 are shared by the wiring board 500H.

The distance between the _two furthest via conductors 511H ₁ and 511H ₂ among the plurality of via conductors 511H is D1. The distance D1 is, the side facing the via conductors 511h ₂ In the via conductor 511h ₁ is a linear distance between the opposite side portions and opposite side portions, the side facing the via conductors 511h ₁ in the via conductor 511h ₂ .

第６実施形態では、複数のヴィア導体５１１Ｈが２つのヴィア導体５１１Ｈ_１，５１１Ｈ_２のみであるため、この２つのヴィア導体５１１Ｈ_１，５１１Ｈ_２の距離Ｄ１が、上記の式を満たせばよい。 As in the fifth embodiment, as shown in FIG. 11B, when the image sensor 300 is viewed in the Z direction, that is, the length of the long side 300X that is the first side of the image sensor 300 when viewed in a plan view. Is X1, and the length of the short side 300Y which is the second side intersecting the long side is Y1. As described in the fifth embodiment, among the plurality of via conductors 511H, it is sufficient that the distance D1 between the _two via conductors 511H ₁ and 511H _{2 that} are farthest apart satisfies the following expression.

In the sixth embodiment, since a plurality of via conductors 511h is only two via conductors 511h _1, 511h _2, the two via conductors 511h _1, 511h ₂ distance D1 may satisfy the above equation.

  If the distance D1 satisfies the above expression, the plurality of via conductors 511H are arranged in a narrow range. Since the plurality of via conductors 511H are arranged in a narrow range, even if an apparently larger closed loop than the closed loop L9 is formed, the induced current flowing through the large closed loop is extremely smaller than the induced current flowing through the closed loop L9. . Therefore, since the plurality of via conductors 511H are arranged in a narrow range, the closed loop of the analog ground can be regarded as a closed loop L9.

Further, when the distance D1 satisfies the following expression, the plurality of via conductors 511H are arranged in a narrower range, and therefore, it is more preferable.

  As described above, according to the sixth embodiment, as shown in FIG. 12, the entire ground wiring 571H is disposed closer to the image sensor 300 than the center C9, so that the area of the closed loop L9 can be reduced. By reducing the area of the closed loop L9, the fluctuation of the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

Here, among the plurality of via conductors 513H in the ground wiring 571H, the two distances via conductors 513H _1, 513H ₂ to farthest to D2. In addition, the distance between the _two via conductors 508H ₁ and 508H _{2 that} are most separated from each other among the plurality of via conductors 508H in the ground wiring 572H is defined as D3. The distance D2 is the side facing the via conductors 513H ₂ in the via conductor 513H ₁ is a linear distance between the opposite side portions and opposite side portions, the side facing the via conductors 513H ₁ in the via conductor 513H ₂ . Distance D3 is the side facing the via conductors 508H ₂ in the via conductor 508H ₁ is a linear distance between the opposite side portions and opposite side portions, the side facing the via conductors 508H ₁ in the via conductor 508H ₂ . In the sixth embodiment, the distance D1 is smaller than the distance D2 and the distance D3. This causes the plurality of via conductors 511H to be arranged in a narrow range, so that the induced current flows more easily through the closed loop L9 than through a large closed loop via the plurality of via conductors 511H. Therefore, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved. In FIG. 12, the distance D2 and the distance D3 are the same, but may be different.

  In the sixth embodiment, the via conductor 511H is disposed to penetrate the conductor pattern 506H of the conductor layer 4H, and electrically connects the conductor pattern 505H of the conductor layer 3H and the conductor pattern 506H of the conductor layer 5H. . Therefore, also in the sixth embodiment, as in the first to fourth embodiments, each via conductor 511H has at least one of the conductor pattern 505H of the conductor layer 3H and the conductor pattern 506H of the conductor layer 5H when viewed in the Z direction. May be arranged so as to avoid the center and the end. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

[Seventh embodiment]
An imaging unit according to the seventh embodiment will be described. In the above-described fifth embodiment, as illustrated in FIG. 10, a case has been described in which the number of via conductors 511 </ b> D electrically connecting the ground wiring 571 </ b> D and the ground wiring 572 </ b> D is two. Instead, three or more may be used. FIG. 13 is a sectional view of an imaging unit 400I according to the seventh embodiment. FIG. 14 is a plan view of a second conductor layer of the wiring board according to the seventh embodiment. FIG. 13 is a schematic diagram illustrating a cross-sectional side view of the imaging unit 400I along the line AA illustrated in FIG. Note that, in the imaging unit 400I of the seventh embodiment, the same components as those of the imaging unit 400 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  As illustrated in FIG. 13, the imaging unit 400I includes an imaging element 300, a wiring board 500I, a frame 602, and a cover glass 603. The wiring board 500I is a printed wiring board in the seventh embodiment. Wiring board 500I has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  Wiring board 500I is a laminated substrate including a plurality of, for example, eight conductor layers 1I to 8I arranged at intervals in the Z direction which is the thickness direction of wiring board 500I. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1I to 8I. A conductor pattern is arranged on each of the conductor layers 1I to 8I. Wiring board 500I has two main surfaces 501I and 502I. The imaging element 300 is mounted on the main surface 501I of the wiring board 500I on the side of the conductor layer 1I.

  The plurality of conductor layers 1I to 8I are laminated in the order of the conductor layer 1I, the conductor layer 2I, the conductor layer 3I, the conductor layer 4I, the conductor layer 5I, the conductor layer 6I, the conductor layer 7I, and the conductor layer 8I from the imaging element 300 side. It is arranged. The conductor layers 1I and 8I are surface layers, that is, outer layers, and the conductor layers 2I to 7I are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502I on the side of the conductor layer 8I. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1I and 8I.

  The image sensor 300 is arranged on the main surface 501I and connected to the wiring board 500I by wire bonding. The image sensor 300 is mounted on the wiring board 500I by wire bonding, but is not limited thereto, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes the pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. As shown in FIG. 13, the wiring board 500I has a ground wiring portion 570I serving as a ground. The ground wiring section 570I includes a ground wiring 571I as a first ground wiring and a ground wiring 572I as a second ground wiring.

The ground wiring 571I is connected to the plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1I. 13, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 13 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. 13, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400I is viewed from the side, that is, when the imaging unit 400I is viewed in the Y direction, a closed loop L10 of an analog ground is formed in the imaging unit 400I over the imaging element 300 and the wiring board 500I. FIG. 13 shows the closed loop L10 by a two-dot chain line.

The closed loop L10 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571I of the wiring board 500I. More specifically, the closed loop L10 includes an analog ground wire 330, a pair of analog ground electrodes 331 ₁ and 331 ₂ , a pair of wires 611 ₁ and 611 ₂ , a pair of ground electrodes 531 ₁ and 531 ₂ , and a ground wire 571I. In.

  The area of the closed loop L10 of the analog ground when viewed in the Y direction is defined as S10. The ground wiring 571I is disposed closer to the image sensor 300 than the center C10 in the Z direction of the wiring board 500I. The center C10 is a center between the two main surfaces 501I and 502I, and is shown by a dashed line in FIG. Since the entire ground wiring 571I is disposed closer to the image sensor 300 than the center C10 in the Z direction of the wiring board 500I, the area S10 of the closed loop L10 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L10 is proportional to the area S10 of the closed loop L10, the induced electromotive force generated in the closed loop L10 can be reduced by reducing the area S10. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  In the seventh embodiment, the ground wiring 571I includes only one conductor pattern 505I that is the first conductor pattern. The conductor pattern 505I is disposed on the conductor layer 1I, which is the surface layer on the side on which the image sensor 300 is mounted on the wiring board 500I. The ground electrode 531 is formed integrally with the conductor pattern 505I. Since the conductor pattern 505I is disposed on the conductor layer 1I, the area S10 of the closed loop L10 can be reduced as much as possible, and the image generated by the imaging element 300 can be effectively suppressed from being disturbed, and Image quality is further improved.

  The ground wiring 572I has a plurality of conductor patterns 506I, which are a plurality of second conductor patterns, and a plurality of via conductors 508I, which are a plurality of third via conductors. The conductor pattern 506I is arranged on the conductor layers 2I to 8I. The plurality of conductor patterns 506I are electrically connected by the plurality of via conductors 508I.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the imaging element 300 be common, and the ground wiring 571I and the ground wiring 572I are electrically connected on the wiring board 500I. The ground wiring 571I is arranged closer to the image sensor 300 than the ground wiring 572I. In the seventh embodiment, the ground wiring 571I and the ground wiring 572I are electrically connected only by the plurality of via conductors 511I, which are the plurality of first via conductors. That is, the analog ground and the digital ground are connected only by the plurality of via conductors 511I. In FIG. 13, via conductors 511I are indicated by hatching different from ground wirings 571I and 572I.

  The ground line 571I is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572I is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. The ground wiring 571I and the ground wiring 572I are electrically connected only by the plurality of via conductors 511I. As described above, the ground of the analog circuit and the ground of the digital circuit of the image sensor 300 is shared by the wiring board 500I.

Here, as shown in FIG. 14, the distance between the _two via conductors 511I ₁ and 511I ₂ which are the most distant from the plurality of via conductors 511I is D1. The distance D1 is, the side facing the via conductors 511i ₂ in the via conductor 511i ₁ is a linear distance between the opposite side portions and opposite side portions, the side facing the via conductors 511i ₁ in the via conductor 511i ₂ .

第７実施形態では、図１４に示すように、３行３列に配置された９つのヴィア導体５１１Ｉがあるため、これら９つのヴィア導体５１１Ｉのうち対角に位置する２つのヴィア導体５１１Ｉ_１，５１１Ｉ_２の距離Ｄ１が、上記の式を満たせばよい。 As in the fifth embodiment, as shown in FIG. 11B, when the image sensor 300 is viewed in the Z direction, that is, the length of the long side 300X that is the first side of the image sensor 300 when viewed in a plan view. Is X1, and the length of the short side 300Y which is the second side intersecting the long side is Y1. As described in the fifth embodiment, among the plurality of via conductors 511I, it is only necessary that the two via conductors 511I ₁ and 511I ₂ be arranged so that the distance D1 satisfies the following expression.

In the seventh embodiment, as shown in FIG. 14, since there are nine via conductors 511I arranged in three rows and three columns, of the nine via conductors 511I, two via conductors 511I ₁ ,. distance D1 511i ₂ may satisfy the above equation.

  If the distance D1 satisfies the above expression, the plurality of via conductors 511I are arranged in a narrow range. Since the plurality of via conductors 511I are arranged in a narrow range, an induced current flowing through the large closed loop is extremely smaller than an induced current flowing through the closed loop L10, even if an apparently larger closed loop is formed than the closed loop L10. . Therefore, since the plurality of via conductors 511I are arranged in a narrow range, the closed loop of the analog ground can be regarded as a closed loop L10.

If the distance D1 satisfies the following expression, the plurality of via conductors 511I are more preferably arranged in a narrower range.

  As described above, according to the seventh embodiment, since the entire ground wiring 571I is disposed closer to the image sensor 300 than the center C10 as shown in FIG. 13, the area of the closed loop L10 can be reduced. By reducing the area of the closed loop L10, the potential fluctuation of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

Here, of the plurality of via conductors 508I in the ground wiring 572I, the distance between the two via conductors 508I ₁ and 508I _{2 that} are the farthest apart is D3. Distance D3 is the side facing the via conductors 508I ₂ in the via conductor 508I ₁ is a linear distance between the opposite side portions and opposite side portions, the side facing the via conductors 508I ₁ in the via conductor 508I ₂ . In the seventh embodiment, the distance D1 is smaller than the distance D3. Accordingly, the plurality of via conductors 511I are arranged in a narrow range, so that the induced current more easily flows through the closed loop L10 than the large closed loop via the plurality of via conductors 511I. Therefore, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  In the seventh embodiment, as shown in FIG. 14, the plurality of via conductors 511I are arranged so as to pass through one hole formed in the conductor pattern 506I of the conductor layer 2I. The plurality of via conductors 511I electrically connect the conductor pattern 505I of the conductor layer 1I and the conductor pattern 506I of the conductor layer 3I, as shown in FIG.

  As shown in FIG. 14, the wiring board 500I of FIG. 13 has a conductor pattern 512I arranged in an opening formed in the conductor pattern 506I in a non-contact state with the conductor pattern 506I of the conductor layer 2I. The conductor pattern 512I is an example of a third conductor pattern. The conductor pattern 512I is arranged on the conductor layer 2I and connects the plurality of via conductors 511I. As a result, intermediate portions of the plurality of via conductors 511I in the Z direction are electrically connected by the conductor patterns 512I.

  In the seventh embodiment, the plurality of via conductors 511I are arranged to penetrate the conductor pattern 506I of the conductor layer 2I, and electrically connect the conductor pattern 505I of the conductor layer 1I and the conductor pattern 506I of the conductor layer 3I. ing.

  The plurality of via conductors 511I are at least the center and end of the conductor pattern 505I of the conductor layer 1I when viewed in the Z direction, and in the seventh embodiment, the center of the conductor pattern 505I of the conductor layer 1I and the center of the conductor pattern 506I of the conductor layer 3I. It is arranged avoiding the end. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

  Note that the ground wiring 571I in the seventh embodiment may be configured similarly to the ground wiring 571H of FIG. 12 described in the sixth embodiment. At this time, as in the sixth embodiment, the distance D1 may be smaller than the distance D2 in FIG.

[Eighth Embodiment]
An imaging unit according to the eighth embodiment will be described. In the eighth embodiment, a case where a plurality of conductor patterns of the second ground wiring are arranged in any one of the conductor layers will be described. FIG. 15 is a sectional view of an imaging unit 400E according to the eighth embodiment. FIG. 16 is a plan view of a second conductor layer and a third conductor layer of the wiring board according to the eighth embodiment. FIG. 15 is a schematic diagram illustrating a side view of a cross section of the imaging unit 400E along the line AA illustrated in FIG. Note that in the imaging unit 400E of the eighth embodiment, the same components as those of the imaging unit 400 of the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

  As shown in FIG. 15, the imaging unit 400E includes an imaging element 300, a wiring board 500E, a frame 602, and a cover glass 603. The wiring board 500E is a printed wiring board in the eighth embodiment. Wiring board 500E has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  The wiring board 500E is a laminated board including a plurality of, for example, eight conductor layers 1E to 8E arranged at intervals in the Z direction which is the thickness direction of the wiring board 500E. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1E to 8E. A conductor pattern is arranged on each of the conductor layers 1E to 8E. Wiring board 500E has two main surfaces 501E and 502E. The imaging element 300 is mounted on the main surface 501E of the wiring board 500E on the side of the conductor layer 1E.

  The plurality of conductor layers 1E to 8E are laminated in the order of the conductor layer 1E, the conductor layer 2E, the conductor layer 3E, the conductor layer 4E, the conductor layer 5E, the conductor layer 6E, the conductor layer 7E, and the conductor layer 8E from the imaging element 300 side. It is arranged. The conductor layers 1E and 8E are surface layers, that is, outer layers, and the conductor layers 2E to 7E are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502E on the side of the conductor layer 8E. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1E and 8E.

  The imaging element 300 is arranged on the main surface 501E and is connected to the wiring board 500E by wire bonding. The image sensor 300 is mounted on the wiring board 500E by wire bonding, but is not limited to this, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes the pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. As shown in FIG. 15, the wiring board 500E has a ground wiring portion 570E serving as a ground. The ground wiring section 570E includes a ground wiring 571E as a first ground wiring and a ground wiring 572E as a second ground wiring.

The ground wiring 571E is connected to the plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1E. The Figure 15, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 15 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. The Figure 15, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400E is viewed from the side, that is, when the imaging unit 400E is viewed in the Y direction, a closed loop L6 of an analog ground is formed in the imaging unit 400E over the imaging element 300 and the wiring board 500E. FIG. 15 shows the closed loop L6 by a two-dot chain line.

The closed loop L6 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571E of the wiring board 500E. More specifically, the closed loop L6 includes an analog ground wire 330, a pair of analog ground electrodes 331 ₁ and 331 ₂ , a pair of wires 611 ₁ and 611 ₂ , a pair of ground electrodes 531 ₁ and 531 ₂ , and a ground wire 571E. In.

  The ground line 572E is a portion other than the ground line 571E as viewed in the Y direction, that is, a portion that does not contribute to the formation of the closed loop L6 of the analog ground. For example, the ground wiring 572E includes a part that forms a closed loop of digital ground together with the digital ground wiring 350 (FIG. 3) of the image sensor 300 when viewed in the Y direction, and a part that does not contribute to the formation of any closed loop.

  Here, the area of the closed loop L6 of the analog ground when viewed in the Y direction, that is, the area of the portion surrounded by the two-dot chain line in FIG. 15 is defined as S6. The ground wiring 571E is disposed closer to the image sensor 300 than the center C6 of the wiring board 500E in the Z direction. The center C6 is the center between the two main surfaces 501E and 502E, and is shown by a dashed line in FIG. Since the entire ground wiring 571E is disposed closer to the image sensor 300 than the center C6 in the Z direction of the wiring board 500E, the area S6 of the closed loop L6 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L6 is proportional to the area S6 of the closed loop L6, the induced electromotive force generated in the closed loop L6 can be reduced by reducing the area S6. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  The ground wiring 571E includes only one conductor pattern 505E that is the first conductor pattern. The conductor pattern 505E is arranged on the conductor layer 1E, which is the surface layer on the side on which the imaging element 300 is mounted on the wiring board 500E. The ground electrode 531 is formed integrally with the conductor pattern 505E. Since the conductor pattern 505E is arranged on the conductor layer 1E, the area S6 of the closed loop L6 can be minimized, and the image generated by the imaging element 300 can be effectively suppressed from being disturbed. Image quality is further improved.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the imaging element 300 be common, and the ground wiring 571E and the ground wiring 572E are electrically connected on the wiring board 500E. The ground wiring 571E is disposed closer to the image sensor 300 than the ground wiring 572E. The ground wiring 571E and the ground wiring 572E are electrically connected by only one via conductor 511E that is a first via conductor arranged at one place so that the closed loop of the analog ground does not spread to the ground wiring 572E. I have. That is, the analog ground and the digital ground are connected only by the via conductor 511E. In FIG. 15, via conductors 511E are indicated by hatching different from ground wirings 571E and 572E.

  The ground line 571E is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572E is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. Further, the ground wiring 571E and the ground wiring 572E are electrically connected by only one via conductor 511E. Since the ground wiring 571E and the ground wiring 572E are electrically connected by only one via conductor 511E, the closed loop L6 of the analog ground does not extend to the ground wiring 572E, and the area S6 can be reduced. Accordingly, it is possible to suppress the image generated by the image sensor 300 from being disturbed, and the quality of the generated image is improved.

  The via conductor 511E is disposed so as to avoid at least the center and the end of the conductor pattern 505E of the conductor layer 1E when viewed in the Z direction. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

  The ground wiring 572E has a plurality of conductor patterns 506E, which are a plurality of second conductor patterns, spaced apart from each other, and a plurality of via conductors 508E, which are a plurality of third via conductors. The conductor pattern 506E is arranged on the conductor layers 2E to 8E. The plurality of conductor patterns 506E are electrically connected by the plurality of via conductors 508E.

  In each of the conductor layers 2E and 3E, a plurality of conductor patterns 506E in FIG. 16 are arranged, and in each of the conductor layers 4E to 8E, one conductor pattern 506E which is a solid pattern is arranged. That is, as shown in FIG. 16, in each of the conductor layers 2E and 3E, the two conductor patterns 506E are not connected to each other. Therefore, the two conductor patterns 506E in each of the conductor layers 2E and 3E are electrically connected to the plurality of via conductors 508E and the conductor patterns 506E arranged in the other conductor layers 4E to 8E. As described above, the plurality of conductor patterns 506E included in the ground wiring 572E only need to be electrically connected by the plurality of via conductors 508E, and the number of conductor patterns 506E arranged in each conductor layer is limited to one. However, there may be more than one.

[Ninth embodiment]
An imaging unit according to a ninth embodiment will be described. FIG. 17 is a sectional view of an imaging unit 400F according to the ninth embodiment. FIG. 18 is a plan view of a second conductor layer of the wiring board according to the ninth embodiment. FIG. 17 is a schematic diagram illustrating a cross-sectional side view of the imaging unit 400F along the line AA illustrated in FIG. Note that, in the imaging unit 400F of the ninth embodiment, the same components as those of the imaging unit 400 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  As shown in FIG. 17, the imaging unit 400F includes an imaging element 300, a wiring board 500F, a frame 602, and a cover glass 603. The wiring board 500F is a printed wiring board in the ninth embodiment. Wiring board 500F has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  The wiring board 500F is a laminated substrate including a plurality of, for example, eight conductor layers 1F to 8F arranged at intervals in the Z direction which is the thickness direction of the wiring board 500F. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1F to 8F. A conductor pattern is arranged on each of the conductor layers 1F to 8F. Wiring board 500F has two main surfaces 501F and 502F. The imaging element 300 is mounted on the main surface 501F on the conductor layer 1F side in the wiring board 500F.

  The plurality of conductor layers 1F to 8F are laminated in the order of the conductor layer 1F, the conductor layer 2F, the conductor layer 3F, the conductor layer 4F, the conductor layer 5F, the conductor layer 6F, the conductor layer 7F, and the conductor layer 8F from the imaging element 300 side. It is arranged. The conductor layers 1F and 8F are surface layers, that is, outer layers, and the conductor layers 2F to 7F are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502F on the conductor layer 8F side. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1F and 8F.

  The image sensor 300 is arranged on the main surface 501F, and is connected to the wiring board 500F by wire bonding. The image sensor 300 is mounted on the wiring board 500F by wire bonding, but is not limited to this, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes the pixel array 310 and an analog ground line 330 electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. As shown in FIG. 17, the wiring board 500F has a ground wiring portion 570F serving as a ground. The ground wiring section 570F includes a ground wiring 571F as a first ground wiring and a ground wiring 572F as a second ground wiring.

The ground wiring 571F is connected to the plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1F. 17, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 17 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. 17, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400F is viewed from the side, that is, when the imaging unit 400F is viewed in the Y direction, a closed loop L7 of an analog ground is formed in the imaging unit 400F, straddling the imaging element 300 and the wiring board 500F. FIG. 17 shows the closed loop L7 by a two-dot chain line.

The closed loop L7 mainly includes the analog ground wiring 330 of the image sensor 300 and the ground wiring 571F of the wiring board 500F. More specifically, the closed loop L7 includes an analog ground wiring 330, a pair of analog ground electrodes 331 ₁ and 331 ₂ , a pair of wires 611 ₁ and 611 ₂ , a pair of ground electrodes 531 ₁ and 531 ₂ , and a ground wiring 571F. In.

  The ground wiring 572F is a part other than the ground wiring 571F when viewed in the Y direction, that is, a part that does not contribute to the formation of the closed loop L7 of the analog ground. For example, the ground wiring 572F includes a part that forms a closed loop of digital ground together with the digital ground wiring 350 (FIG. 3) of the image sensor 300 when viewed in the Y direction, and a part that does not contribute to the formation of any closed loop.

  Here, the area of the closed loop L7 of the analog ground when viewed in the Y direction, that is, the area of the portion surrounded by the two-dot chain line in FIG. 17 is defined as S7. The ground wiring 571F is disposed closer to the image sensor 300 than the center C7 in the Z direction of the wiring board 500F. The center C7 is the center between the two main surfaces 501F and 502F, and is shown by a dashed line in FIG. Since the entire ground wiring 571F is disposed closer to the image sensor 300 than the center C7 in the Z direction of the wiring board 500F, the area S7 of the closed loop L7 of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop L7 is proportional to the area S7 of the closed loop L7, the induced electromotive force generated in the closed loop L7 can be reduced by reducing the area S7. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  The ground wiring 571F includes only one conductor pattern 505F that is the first conductor pattern. The conductor pattern 505F is arranged on the conductor layer 1F, which is the surface layer on the side on which the imaging element 300 is mounted on the wiring board 500F. The ground electrode 531 is formed integrally with the conductor pattern 505F. Since the conductor pattern 505F is disposed on the conductor layer 1F, the area S7 of the closed loop L7 can be minimized, and the image generated by the imaging element 300 can be effectively suppressed from being disturbed. Image quality is further improved.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the imaging element 300 be common, and the ground wiring 571F and the ground wiring 572F are electrically connected on the wiring board 500F. The ground wiring 571F is disposed closer to the image sensor 300 than the ground wiring 572F. The ground wiring 571F and the ground wiring 572F are electrically connected by only one via conductor 511F which is a first via conductor arranged at one place so that the closed loop of the analog ground does not spread to the ground wiring 572F. I have. That is, the analog ground and the digital ground are connected only by the via conductor 511F. In FIG. 17, the via conductor 511F is indicated by hatching different from the ground wirings 571F and 572F.

  The ground line 571F is electrically connected to the analog ground line 330 of the image sensor 300, and the ground line 572F is electrically connected to the digital ground line 350 (FIG. 3) of the image sensor 300. The ground wiring 571F and the ground wiring 572F are electrically connected by only one via conductor 511F. Since the ground wiring 571F and the ground wiring 572F are electrically connected only by one via conductor 511F, the closed loop of the analog ground does not extend to the ground wiring 572F, and the area S7 can be reduced. Accordingly, it is possible to suppress the image generated by the image sensor 300 from being disturbed, and the quality of the generated image is improved.

  The via conductor 511F is arranged so as to avoid at least the center and the end of the conductor pattern 505F of the conductor layer 1F when viewed in the Z direction. Thereby, it is possible to effectively suppress the image generated by the imaging element 300 from being disturbed, and the quality of the generated image is further improved.

  The ground wiring 572F has a plurality of conductor patterns 506F, which are a plurality of second conductor patterns, and a plurality of via conductors 508F, which are a plurality of third via conductors. The conductor pattern 506F is arranged on the conductor layers 2F to 8F. The plurality of conductor patterns 506F are electrically connected by the plurality of via conductors 508F.

  In the conductor layer 2F, one conductor pattern 506F is arranged, in the conductor layer 3F, a plurality of conductor patterns 506F are arranged, and in the conductor layers 4F to 8F, one solid pattern 506F is arranged. As shown in FIG. 18, the conductor pattern 506F arranged on the conductor layer 2F may not be a solid pattern. That is, the shape of each conductor pattern 506F is not limited to a solid pattern, and may be arbitrary.

[Tenth embodiment]
An imaging unit according to the tenth embodiment will be described. FIGS. 19 and 20 are cross-sectional views of an imaging unit 400G according to the tenth embodiment. FIG. 21 is a plan view of the first conductor layer of the wiring board according to the tenth embodiment. FIG. 19 is a schematic diagram illustrating a side view of a cross section of the imaging unit 400G along the line A1-A1 illustrated in FIG. FIG. 20 is a schematic diagram illustrating a side view of a cross section of the imaging unit 400G along the line A2-A2 illustrated in FIG. In the tenth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIGS. 19 and 20, the imaging unit 400G includes an imaging element 300, a wiring board 500G, a frame 602, and a cover glass 603. The wiring board 500G is a printed wiring board in the tenth embodiment. Wiring board 500G has a conductor portion and an insulator portion. The conductor portion is made of a conductive metal material, for example, copper or gold. The insulator portion is made of an insulating material having electrical insulation properties, for example, an epoxy resin.

  The wiring board 500G is a laminated substrate including a plurality of, for example, eight conductor layers 1G to 8G arranged at intervals in the Z direction which is the thickness direction of the wiring board 500G. An insulator layer is arranged between two adjacent conductor layers among the conductor layers 1G to 8G. A conductor pattern is arranged on each of the conductor layers 1G to 8G. Wiring board 500G has two main surfaces 501G and 502G. The image sensor 300 is mounted on the main surface 501G of the wiring board 500G on the side of the conductor layer 1G.

  The plurality of conductor layers 1G to 8G are laminated in the order of the conductor layer 1G, the conductor layer 2G, the conductor layer 3G, the conductor layer 4G, the conductor layer 5G, the conductor layer 6G, the conductor layer 7G, and the conductor layer 8G from the imaging element 300 side. It is arranged. The conductor layers 1G and 8G are surface layers, that is, outer layers, and the conductor layers 2G to 7G are inner layers. A circuit component 601 such as a capacitor is mounted on the main surface 502G on the side of the conductor layer 8G. The number of conductor layers is not limited to eight, but may be two or more. However, considering the arrangement of the wiring, the number of conductor layers is preferably 3 or more, more preferably 4 or more. Further, a solder resist (not shown) may be provided on the conductor layers 1G and 8G.

  The image sensor 300 is arranged on the main surface 501G and is connected to the wiring board 500G by wire bonding. The image pickup device 300 is mounted on the wiring board 500G by wire bonding, but is not limited to this, and may be mounted on the wiring board by flip chip bonding. In this case, the image sensor and the wiring board are connected by a plurality of metal members such as a plurality of solder balls.

  As shown in FIG. 3, the image sensor 300 has an analog circuit 370. The analog circuit 370 includes a pixel array 310 and an analog ground line 330 illustrated in FIG. 19 that is electrically connected to the pixel array 310. Further, the imaging element 300 includes a digital circuit 380. The digital circuit 380 has a digital ground wiring 350. The analog circuit 370 has an analog power supply wiring 320 illustrated in FIG. 20 electrically connected to the pixel array 310. Digital circuit 380 has digital power supply wiring 340. As shown in FIG. 19, the wiring board 500G has a ground wiring portion 570G serving as a ground. The ground wiring section 570G includes a ground wiring 571G as a first ground wiring and a ground wiring 572G as a second ground wiring.

The ground wiring 571G is connected to the plurality of ground electrodes 531. The plurality of ground electrodes 531 are arranged on the conductor layer 1G. 19, among the plurality of ground electrodes 531, are shown in the X direction to be spaced a pair of ground electrodes ₅₃₁ 1, 531 _2. The analog ground wiring 330 is connected to the plurality of analog ground electrodes 331. FIG. 19 illustrates a pair of analog ground electrodes 331 ₁ and 331 ₂ that are spaced apart in the X direction among the plurality of analog ground electrodes 331. The plurality of analog ground electrodes 331 and the plurality of ground electrodes 531 are electrically connected by a plurality of wires 611. The plurality of wires 611 are included in the plurality of wires 610 of FIG. 19, among the plurality of wires 611, electrically connected to the wire 611 ₁ to electrically connect the analog ground electrode 331 ₁ and the ground electrode 531 ₁ and an analog ground electrode 331 ₂ and the ground electrode 531 ₂ It illustrates a wire 611 _2.

  When the imaging unit 400G is viewed from the side, that is, when the imaging unit 400G is viewed in the Y direction, a closed loop of an analog ground is formed in the imaging unit 400G across the imaging element 300 and the wiring board 500G.

  The ground wire 572G is a portion other than the ground wire 571G when viewed in the Y direction, that is, a portion that does not contribute to the formation of a closed loop of analog ground. For example, the ground wiring 572G includes a part that forms a closed loop of digital ground together with the digital ground wiring 350 (FIG. 3) of the image sensor 300 when viewed in the Y direction, and a part that does not contribute to the formation of any closed loop.

  As shown in FIG. 19, the ground wiring 571G is disposed closer to the image sensor 300 than the center C8 in the Z direction of the wiring board 500G. The center C8 is the center between the two main surfaces 501G and 502G, and is shown by a dashed line in FIG. Since the entire ground wiring 571G is disposed closer to the image sensor 300 than the center C8 in the Z direction of the wiring board 500G, the area of the closed loop of the analog ground can be reduced. Since the induced electromotive force generated in the closed loop is proportional to the area of the closed loop, the induced electromotive force generated in the closed loop can be reduced by reducing the area of the closed loop. Therefore, the fluctuation in the potential of the analog ground can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  The ground wiring 571G is composed of only one conductor pattern 505G that is the first conductor pattern. The conductor pattern 505G is arranged on the conductor layer 1G, which is the surface layer on the side on which the imaging element 300 is mounted on the wiring board 500G. Accordingly, the area of the closed loop can be reduced as much as possible, and the disturbance of the image generated by the image sensor 300 can be effectively suppressed, and the quality of the generated image is further improved.

  The ground wiring 572G includes a plurality of conductor patterns 506G, which are a plurality of second conductor patterns, and a plurality of via conductors 508G, which are a plurality of third via conductors. The conductor pattern 506G is arranged on the conductor layers 2G to 8G. The plurality of conductor patterns 506G are electrically connected by the plurality of via conductors 508G.

  It is preferable that the ground of the analog circuit and the ground of the digital circuit of the image sensor 300 are shared, and the ground wiring 571G and the ground wiring 572G are electrically connected to each other on the wiring board 500G. The ground wiring 571G is disposed closer to the image sensor 300 than the ground wiring 572G. In the tenth embodiment, the ground wiring 571G and the ground wiring 572G are electrically connected by only one via conductor 511G that is a first via conductor arranged at one place. That is, the analog ground and the digital ground are connected only by the via conductor 511G. In FIG. 19, the via conductor 511G is indicated by hatching different from the ground wirings 571G and 572G.

  As described in the first embodiment, the closed loop in the imaging unit 400G has different resistance to magnetic field noise depending on the type of the connected circuit. Specifically, in the imaging unit 400G, the closed loop of the power supply of the analog circuit (hereinafter, referred to as “analog power supply”) is more resistant to magnetic field noise than the closed loop of the power supply of the digital circuit (hereinafter, referred to as “digital power supply”). Is low. That is, after the closed loop of the analog ground, the closed loop of the analog power supply is susceptible to the magnetic field noise. In particular, the wiring related to the pixel array 310 in FIG. 3 has a low resistance to magnetic field noise because it directly affects pixel signals. In addition, the lower the impedance of the wiring, the easier the induced current flows, and the lower the resistance to magnetic field noise. When a voltage distribution occurs in the closed loop of the analog power supply due to the induced electromotive force, the pixel signal fluctuates due to the power supply potential distribution.

Wiring board 500G includes power supply wiring 581G, as shown in FIG. The power supply wiring 581G is connected to the plurality of power supply electrodes 521. FIG. 20 illustrates a pair of power supply electrodes 521 ₁ and 521 ₂ that are separated from each other in the X direction among the plurality of power supply electrodes 521. The analog power supply wiring 320 is connected to the plurality of analog power supply electrodes 321. Figure 20, among the plurality of analog power supply electrodes 321, are shown in the X direction to be spaced a pair of analog power electrodes ₃₂₁ 1, 321 _2. The plurality of analog power electrodes 321 and the plurality of power electrodes 521 are electrically connected by a plurality of wires 612. The plurality of wires 612 are included in the plurality of wires 610 of FIG. 20 shows, among the plurality of wires 612, electrically connected to the wire 612 ₁ to electrically connect the analog power electrodes 321 ₁ and the power supply electrode 521 ₁ and an analog power electrodes 321 ₂ and the power supply electrode 521 ₂ It illustrates a wire 612 _2.

  When the imaging unit 400G is viewed from the side, that is, when the imaging unit 400G is viewed in the Y direction, a closed loop L80 of an analog power supply is formed in the imaging unit 400G, straddling the imaging element 300 and the wiring board 500G. FIG. 20 shows the closed loop L80 by a two-dot chain line.

  Here, the area of the closed loop L80 of the analog power supply as viewed in the Y direction, that is, the area of the portion surrounded by the two-dot chain line in FIG. 20 is defined as S80. The power supply wiring 581G is disposed closer to the image sensor 300 than the center C8. Since the entire power supply wiring 581G is disposed closer to the image sensor 300 than the center C8 of the wiring board 500G in the Z direction, the area S80 of the closed loop L80 of the analog power supply can be reduced. Since the induced electromotive force generated in the closed loop L80 is proportional to the area S80 of the closed loop L80, the induced electromotive force generated in the closed loop L80 can be reduced by reducing the area S80. Therefore, the fluctuation in the potential of the analog power supply can be reduced, and thereby, it is possible to prevent the pattern noise from being generated in the output image of the image sensor 300. That is, disturbance of the image generated by the image sensor 300 can be suppressed, and the quality of the generated image is improved.

  In the tenth embodiment, the power supply wiring 581G is composed of only one conductor pattern 515G. As shown in FIGS. 20 and 21, the conductor pattern 515G is disposed on the conductor layer 1G, which is the surface layer on the side on which the imaging element 300 is mounted in the wiring board 500G. Since the conductor pattern 515G is disposed on the conductor layer 1G, the area S80 of the closed loop L80 can be reduced as much as possible, and the image generated by the imaging element 300 can be effectively suppressed from being disturbed. Image quality is further improved.

  As shown in FIGS. 20 and 21, the power supply electrode 521 is formed integrally with the conductor pattern 515G. A conductor pattern 516G connected to the power terminal of the circuit component 601 is arranged on the conductor layer 8G. The conductor pattern 516G is electrically connected to the conductor pattern 515G by one via conductor 517G. Power is supplied to the analog circuit and the circuit component 601 of the image sensor 300 through these wirings. In addition, by reducing the distance between the via conductor 511G and the via conductor 517G, the area of the closed loop including the analog power supply and the analog ground can be reduced.

  The present invention is not limited to the embodiments described above, and many modifications are possible within the technical idea of the present invention. Further, the effects described in the embodiments merely enumerate the most preferable effects resulting from the present invention, and the effects according to the present invention are not limited to those described in the embodiments.

100: Camera (imaging device), 300: Image sensor, 301: Light receiving surface, 310: Pixel array, 330: Analog ground wiring, 400: Imaging unit, 500: Wiring board, 511: Via conductor (first via conductor), 571: ground wiring (first ground wiring), 572: ground wiring (second ground wiring)

Claims (23)

An image sensor having an analog circuit including analog ground wiring;
A wiring board on which the image sensor is mounted,
The wiring board,
A first ground wiring connected to the analog ground wiring and forming a closed loop with the analog ground wiring when viewed from the side;
An image pickup unit, comprising: a second ground wiring connected to the first ground wiring only by a first via conductor. The imaging unit according to claim 1,
The imaging unit according to claim 1, wherein the first ground wiring is disposed closer to the image sensor than a center in a thickness direction of the wiring board. The imaging unit according to claim 1, wherein
The image pickup unit, wherein the first ground wiring is arranged closer to the image sensor than the second ground wiring in a thickness direction of the wiring board. The imaging unit according to claim 2 or 3,
The imaging unit according to claim 1, wherein the first ground wiring includes only one first conductor pattern disposed on a surface layer of the wiring board. The imaging unit according to claim 2 or 3,
The first ground wiring includes a plurality of first conductor patterns arranged at an interval from each other, and a plurality of second via conductors connecting the plurality of first conductor patterns.
An imaging unit, wherein at least one of the plurality of first conductor patterns is arranged on a surface layer of the wiring board. The imaging unit according to any one of claims 1 to 5,
The image sensor has a digital circuit including digital ground wiring,
The imaging unit, wherein the second ground line is connected to the digital ground line. The imaging unit according to any one of claims 1 to 6,
The analog circuit includes an analog power supply wiring,
The image pickup unit, wherein the wiring board is connected to the analog power supply wiring, and has a power supply wiring forming a closed loop with the analog power supply wiring when viewed from the side. The imaging unit according to any one of claims 1 to 7,
The imaging unit, wherein the analog circuit includes a pixel array having a plurality of pixels. An image sensor having an analog circuit including analog ground wiring;
A wiring board on which the image sensor is mounted,
The wiring board,
A first ground wiring connected to the analog ground wiring and forming a closed loop with the analog ground wiring when viewed from the side;
A second ground wiring connected to the first ground wiring only with a plurality of first via conductors,
In plan view, the length of the first side of the image sensor is X1, the length of the second side intersecting the first side is Y1, and the most distant of the plurality of first via conductors is 2 When the distance between two first via conductors is D1,

An imaging unit characterized by satisfying the following. The imaging unit according to claim 9,
The imaging unit according to claim 1, wherein the first ground wiring is disposed closer to the image sensor than a center in a thickness direction of the wiring board. The imaging unit according to claim 9, wherein
The image pickup unit, wherein the first ground wiring is arranged closer to the image sensor than the second ground wiring in a thickness direction of the wiring board. The imaging unit according to claim 10, wherein
The imaging unit according to claim 1, wherein the first ground wiring includes only one first conductor pattern disposed on a surface layer of the wiring board. The imaging unit according to claim 10, wherein
The first ground wiring includes a plurality of first conductor patterns arranged at an interval from each other, and a plurality of second via conductors connecting the plurality of first conductor patterns.
An imaging unit, wherein at least one of the plurality of first conductor patterns is arranged on a surface layer of the wiring board. The imaging unit according to claim 13,
The distance between the two first via conductors that are the most separated from the plurality of first via conductors is smaller than the distance between the two second via conductors that are the most separated from the plurality of second via conductors. An imaging unit, characterized in that: The imaging unit according to any one of claims 9 to 14,
The second ground wiring includes a plurality of second conductor patterns arranged at intervals from each other and a plurality of third via conductors connecting the plurality of second conductor patterns.
The distance between the two furthest first via conductors of the plurality of first via conductors is smaller than the distance between the furthest two third via conductors of the plurality of third via conductors. An imaging unit, characterized in that: The imaging unit according to any one of claims 9 to 15,
The image pickup unit, wherein the wiring board has a third conductor pattern connecting the plurality of first via conductors. The imaging unit according to any one of claims 9 to 16,
The image sensor has a digital circuit including digital ground wiring,
The imaging unit, wherein the second ground line is connected to the digital ground line. The imaging unit according to any one of claims 9 to 17,
The analog circuit includes an analog power supply wiring,
The image pickup unit, wherein the wiring board has a power supply line connected to the analog power supply line and forming a closed loop with the analog power supply line. The imaging unit according to any one of claims 9 to 18,
The imaging unit, wherein the analog circuit includes a pixel array having a plurality of pixels. A housing,
An inductor element disposed inside the housing,
An imaging apparatus comprising: the imaging unit according to any one of claims 1 to 19 disposed inside the housing. The imaging device according to claim 20,
The imaging device according to claim 1, wherein the inductor element is a coil that mechanically drives the imaging unit. A housing,
The imaging unit according to any one of claims 1 to 19, wherein the imaging unit is disposed inside the housing.
An image pickup apparatus, comprising: a mount to which a lens barrel having an optical system and an inductor element can be attached and detached. The imaging device according to claim 22,
The imaging device according to claim 1, wherein the inductor element is a coil that mechanically drives the optical system.

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