Image capturing apparatus

Abstract

To provide an image capturing apparatus capable of suppressing the degradation in detection accuracy of position detecting elements when the temperature inside the apparatus rises.SOLUTION: An image capturing apparatus 10 comprises a shake correction unit 20 including a fixed portion, and a movable portion which is movably arranged relative to the fixed portion within a predetermined range in a plane. The movable portion includes: an imaging element having an imaging surface orthogonal to an optical axis; a movable member that holds the imaging element; a first substrate attached to the movable member; and position detecting elements that are arranged, as viewed from an optical axis direction, at positions overlapping the imaging element and mounted on the first substrate. The fixed portion has position detecting magnets arranged at positions opposed to the position detecting elements. A path that transfers heat generated in the imaging element most readily to the position detecting elements is a path passing through the movable member and the first substrate, and the first substrate is lower in thermal conductivity than the movable member.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to an imaging device, and more particularly to an imaging device equipped with a drive device that performs position control. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a driving device that moves a movable part relative to a fixed part within a plane.

[0003] An example of an application of such a drive device is a shake correction mechanism mounted on an imaging device. In the shake correction mechanism, an imaging element is mounted on a movable part, and the movable part is driven to cancel out the shake based on the amount of shake detected by a predetermined sensor.

[0004] When the movable part is driven, its position is controlled while detecting its position relative to the fixed part. A known method for detecting the position of the movable part is to place a magnet on one of the fixed part and the movable part, and a magnetic sensor that outputs a voltage proportional to magnetic flux density on the other. For example, Patent Document 1 proposes a configuration in which a magnetic sensor is placed on the movable part and a magnet is placed on the fixed part, with the magnetic sensor placed on a substrate on which an imaging element is mounted, and the magnet facing the magnetic sensor.

[0005] With this arrangement, the magnetic flux density reaching the magnetic sensor from the magnet changes in response to changes in the positions of the movable and fixed parts, causing the output voltage of the magnetic sensor to change, and the position of the movable part is detected based on the output voltage value.

[0006] In order to improve the accuracy of the image stabilization mechanism, the accuracy of detecting the position of the moving part is one of the important factors. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6846532 Summary of the Invention [Problem to be solved by the invention]

[0008] However, when an imaging device is used for video recording, the temperature of the board on which the imaging element is mounted can rise sharply. Therefore, if the magnetic sensor is mounted on the same board as the imaging element as in Patent Document 1, the temperature change of the magnetic sensor can become large.

[0009] Magnetic sensors also have the characteristic that their output changes in response to temperature changes, so changes in the temperature of the magnetic sensor can cause the output of the magnetic sensor to change, which can result in a decrease in the accuracy of position detection of the moving part.

[0010] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an imaging device that can suppress a decrease in the detection accuracy of a position detecting element when the temperature inside the device rises. [Means for solving the problem]

[0011] In order to solve the above problem, the imaging device of claim 1 of the present invention is an imaging device equipped with a drive mechanism having a first unit and a second unit arranged to be movable relative to the first unit within a predetermined range in a plane, wherein the second unit comprises an imaging element having an imaging surface perpendicular to an optical axis, a movable member that holds the imaging element, a first board attached to the movable member, and a position detection element that is arranged in a position that overlaps with the imaging element when viewed from the direction of the optical axis and is mounted on the first board, the first unit has a position detection magnet that is arranged in a position opposite the position detection element, the path that heat generated by the imaging element takes to transfer most easily to the position detection element is through the movable member and the first board, and the first board has a lower thermal conductivity than the movable member.

[0012] In order to solve the above problem, the imaging device of claim 10 of the present invention is an imaging device equipped with a drive mechanism having a first unit and a second unit arranged to be movable relative to the first unit within a predetermined range in a plane, wherein the second unit comprises an imaging element having an imaging surface perpendicular to an optical axis, a movable member that holds the imaging element, a first substrate attached to the movable member, and a position detection element that is arranged in a position overlapping with the imaging element when viewed from the direction of the optical axis and is mounted on the first substrate, the first unit has a position detection magnet that is arranged in a position opposite the position detection element, the first substrate has a lower thermal conductivity than the movable member, and the position detection element is not in contact with a member having a higher thermal conductivity than the first substrate. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an imaging device that can suppress a decrease in the detection accuracy of a position detection element when the temperature inside the device rises. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating a schematic configuration of an imaging device according to an embodiment of the present invention. [Figure 2] 2 is an exploded perspective view of the image stabilization unit in FIG. 1, which includes a movable part and a fixed part. [Figure 3] FIG. 10 is another exploded perspective view of the image stabilization unit. [Figure 4] FIG. [Figure 5] FIG. 10 is another exploded perspective view of the movable portion. [Figure 6] 1 is an exploded perspective view of a biasing magnetic circuit and a detecting magnetic circuit formed by combining a movable part and a fixed part. FIG. [Figure 7] 3A and 3B are a projection view and a cross-sectional view in the optical axis direction of the detection magnetic circuit when the movable part is positioned at the center of movement. [Figure 8]4A and 4B are a projection view and a cross-sectional view of the detection magnetic circuit in the optical axis direction when the movable part is positioned at the vibration isolation control end. [Figure 9] 2 is an exploded perspective view of a component of a heat dissipation path of the imaging element in FIG. 1. FIG. [Figure 10] 3A and 3B are a projection view and a cross-sectional view in the optical axis direction of a component of a heat dissipation path of an imaging element; DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, the description will be given taking as an example a configuration in which a drive unit according to the present invention is applied to an image stabilization device for an imaging device, but application examples of the drive unit according to the present invention are not limited to image stabilization devices.

[0016] FIG. 1 is a diagram illustrating a schematic configuration of an imaging device 10 according to an embodiment of the present invention.

[0017] The imaging device 10 is a so-called mirrorless digital camera, and has an imaging device body 10a (hereinafter referred to as "body portion 10a") and a lens barrel 10b that is detachable from the body portion 10a.

[0018] Main body 10a includes imaging element 11 having imaging surface 11a, main body-side mount member 13a, base member 13c, camera control unit 14, shake correction control unit 15, vibration detection unit 16, image processing unit 17, and shake correction unit 20. Lens barrel 10b includes imaging optical system 12 and lens-side mount member 13b.

[0019] A virtual light ray representing the light beam irradiated onto the imaging surface 11a of the imaging element 11 via the imaging optical system 12 is referred to as the "imaging optical axis 12a" (hereinafter referred to as the "optical axis 12a"), and a plane perpendicular to the optical axis 12a is referred to as the "optical axis perpendicular plane" (hereinafter referred to as the "optical axis perpendicular plane 12c"). The optical axis 12a passes through the center of the imaging surface 11a and is perpendicular to the imaging surface 11a. In addition, to clarify the arrangement and positional relationship of each component constituting the imaging device 10 within the imaging device 10, the X, Y, and Z directions, which are perpendicular to each other, are defined as shown in FIG. 1. The Z direction is parallel to the optical axis 12a, the X direction is the width direction of the imaging device 10, and the Y direction is the height direction of the imaging device 10. When the X and Z directions are both in a horizontal plane, the Y direction is vertical. Therefore, in this case, the optical axis perpendicular plane 12c is the XY plane.

[0020] The imaging element 11 is composed of a photoelectric conversion element such as a CMOS image sensor or a CCD image sensor, and is arranged with its imaging surface 11a facing the subject (the lens barrel 10b side) and perpendicular to the optical axis 12a. The imaging element 11 generates an image signal by photoelectrically converting an optical image of the subject formed on the imaging surface 11a by the imaging optical system 12. The image signal generated by the imaging element 11 is converted into image data through various processes in the image processing unit 17 and stored in a memory (storage device) not shown.

[0021] The camera control unit 14 is a calculation means within a main IC (not shown), and controls the overall operation of the imaging device 10 by receiving input operations from a user via an operation means (not shown).

[0022] The imaging optical system 12 is composed of a lens group arranged inside the lens barrel 10b, which forms an image of a light beam incident from the subject side on the imaging surface 11a of the imaging element 11. While FIG. 1 shows three lenses included in the lens group, the number of lenses included in the lens group is not limited to three and may be one or more. In the imaging device 10, in order to position the imaging element 11 with high positional accuracy relative to the optical axis 12a, the imaging element 11 is attached to a base member 13c provided on the main body 10a, and the lens barrel 10b is also connected to the base member 13c. In this case, the imaging element 11 is attached to the base member 13c via the image stabilization unit 20. The lens barrel 10b is also connected to the base member 13c via the lens-side mount member 13b and the main body-side mount member 13a.

[0023] The image stabilization unit 20 (drive mechanism) corrects image blur caused by vibrations in the imaging device 10 by moving the imaging element 11 in a direction perpendicular to the optical axis or rotating it within the plane 12c perpendicular to the optical axis, thereby enabling a clear image of the subject to be obtained. Specifically, if the orientation of the imaging device 10 changes relative to the subject during imaging, the imaging position of the subject light beam on the imaging surface 11a of the imaging element 11 changes, causing blur in the image obtained through the imaging element 11. In this case, if the change in orientation of the imaging device 10 is sufficiently small, the change in the imaging position is uniform within the imaging surface 11a and can be considered as at least one of a translational movement and a rotational movement within the plane 12c perpendicular to the optical axis (image plane blur). Therefore, by executing at least one of a translational movement and a rotational movement of the imaging element 11 within the plane 12c perpendicular to the optical axis to cancel out this image plane blur, a clear image of the subject with image blur corrected can be obtained. The image stabilization unit 20 may be configured to move the image sensor 11 in a direction parallel to the image pickup surface 11a, while also moving the image sensor 11 in a direction perpendicular to the image pickup surface 11a.

[0024] As will be described later with reference to Figure 2 etc., the image stabilization unit 20 generally includes a fixed portion 20a, a movable portion 20b, and a plurality of drive force generating portions. The fixed portion 20a is fixed to the base member 13c, and the movable portion 20b holds the image sensor 11. The movable portion 20b is supported by the fixed portion 20a with three degrees of freedom, and is arranged to be movable and rotatable relative to the fixed portion 20a within the plane 12c orthogonal to the optical axis. In other words, the image stabilization unit 20 is configured as a drive device (a so-called XYθ stage) capable of drive control on three axes, and is capable of moving and rotating the image sensor 11 within the plane 12c orthogonal to the optical axis.

[0025] The vibration detection unit 16 is configured with a gyro sensor, an acceleration sensor, etc., and is a shake detection means that detects angular velocity and acceleration in each direction of the imaging device 10 as shake information of the imaging device 10.

[0026] The shake correction control unit 15 calculates the amount of angular change and the amount of movement in each direction of the imaging device 10 based on shake information such as angular velocity and acceleration detected by the vibration detection unit 16. Furthermore, the shake correction control unit 15 calculates a target movement value for the imaging element 11 based on the shake information detected by the vibration detection unit 16, and controls the drive of the shake correction unit 20, thereby controlling the movement of the imaging element 11. Since any known method can be used to calculate the amount of angular change, the amount of movement, and the target movement value based on the shake information, a detailed description thereof will be omitted.

[0027] Next, the detailed configuration of the image stabilization unit 20 will be described.

[0028] 2 and 3 are exploded perspective views of the image stabilization unit 20, with the image stabilization unit 20 viewed from different directions in FIGS. 2 and 3. The image stabilization unit 20 comprises a fixed part 20a (first unit) and a movable part 20b (second unit). Note that in FIGS. 2 and 3, the movable part 20b is shown unexploded, while the fixed part 20a is shown exploded. The fixed part 20a and the movable part 20b are each formed by combining one or more members.

[0029] The fixed portion 20a has a fixed member 21, a first rear yoke 22a, a second rear yoke 22b, a first rear magnet group 23a, a second rear magnet group 23b, and a third rear magnet group 23c. The first rear magnet group 23a and the second rear magnet group 23b are fixed to the first rear yoke 22a, and the third rear magnet group 23c is fixed to the second rear yoke 22b, respectively, with an adhesive or the like.

[0030] The fixed part 20a also has a first pillar member 24a, a second pillar member 24b, a third pillar member 24c, a front yoke 25, a first front magnet group 26a, a second front magnet group 26b, and a third front magnet group 26c. The front yoke 25 is fixed to the fixed member 21 with screws via the first pillar member 24a, the second pillar member 24b, and the third pillar member 24c. The first front magnet group 26a, the second front magnet group 26b, and the third front magnet group 26c are each fixed to the front yoke 25 with an adhesive or the like.

[0031] The fixed portion 20a further includes a detection magnet group 27, a detection yoke 28, a restricting member 29, and a cover 30. The detection magnet group 27 is composed of a first detection magnet group 27a, a second detection magnet group 27b, and a third detection magnet group 27c. In this embodiment, the first detection magnet group 27a, the second detection magnet group 27b, and the third detection magnet group 27c are each composed of two magnets magnetized in the optical axis direction (Z direction) and arranged with a gap between them so that they generate magnetic fields in opposite directions. However, this is not limited to this, and a single magnet magnetized with two poles may also be used. Each of the detection magnet group 27 is fixed to the detection yoke 28 with adhesive or the like. The first rear yoke 22a, the second rear yoke 22b, the front yoke 25, and the detection yoke 28 function as yokes, and therefore, magnetic materials are used.

[0032] The fixed part 20a is referred to as the fixed part 20a because it is a unit that serves as a reference for the position when the movable part 20b moves, but the fixed part 20a may also be configured to be held movably so that its position can be adjusted relative to the main body part 10a.

[0033] Furthermore, as will be described later, the fixed portion 20a is configured to support the movable portion 20b via multiple balls, but for example, the base member 13c and the movable portion 20b may be connected by a spring or wire, etc., to support the movable portion 20b.

[0034] 4 and 5 are exploded perspective views of the movable portion 20b, and the direction in which the movable portion 20b is viewed is different between FIG. 4 and FIG.

[0035] The movable portion 20b has an imaging element holding member 31 and the imaging element 11, and the imaging element 11 is fixed to the imaging element holding member 31 (movable member) with screws, adhesive, or the like (not shown).

[0036] The movable section 20b also has a mask 32a, an infrared absorption filter 32b, and an optical low-pass filter 32c. The mask 32a, the infrared absorption filter 32b, and the optical low-pass filter 32c are held by a holder member 32d and a holder metal plate 32e, and are fixed to the image sensor 11 with an adhesive member or the like. Note that the configuration may not include at least one of the mask 32a, the infrared absorption filter 32b, and the optical low-pass filter 32c.

[0037] The movable part 20b further includes a first coil 33a, a second coil 33b, a third coil 33c, and a driving FPC 34. The driving FPC 34 is electrically connected to the first coil 33a, the second coil 33b, and the third coil 33c. The driving FPC 34 is disposed so as to overlap the first coil 33a, the second coil 33b, and the third coil 33c on the optical axis projection plane (on the XY plane when viewed from the Z direction), and is fixed to the imaging element holding member 31 with an adhesive or the like.

[0038] The imaging element holding member 31 has a first opening 31a, a second opening 31b, and a third opening 31c. The first coil 33a is disposed inside the first opening 31a, the second coil 33b is disposed inside the second opening 31b, and the third coil 33c is disposed inside the third opening 31c.

[0039] Furthermore, the movable part 20b is provided with a connecting member 38 (movable member), which bridges the opening 31i of the imaging element holding member 31 and is fixed to the imaging element holding member 31 with screws 45 on both sides of the optical axis. The connecting member 38 is provided with contact portions 38i in two locations, and the contact portions 38i come into contact with the restricting members 29 of the fixed part 20a, thereby restricting the movement of the movable part 20b within the plane 12c orthogonal to the optical axis within a predetermined range.

[0040] A thrust yoke 40 (magnetic member) and a heat transfer member 39 are fixed to one side of the optical axis orthogonal plane 12c of the connecting member 38, and a detection FPC 36 (first substrate) is fixed to the other side, each with an adhesive or the like. A magnetic material is used for the thrust yoke 40 to fulfill the role of a yoke.

[0041] A detector 35 (position detection element) is mounted on the detection FPC 36. The detector 35 uses a Hall element or the like, and is composed of a first detector 35a, a second detector 35b, and a third detector 35c.

[0042] The connecting member 38 has a first opening 38a, a second opening 38b, and a third opening 38c. The first detector 35a is disposed inside the first opening 38a, the second detector 35b is disposed inside the second opening 38b, and the third detector 35c is disposed inside the third opening 38c. In this manner, the first detector 35a, the second detector 35b, and the third detector 35c are configured not to contact any components other than the detection FPC 36. Furthermore, the first detector 35a, the second detector 35b, and the third detector 35c are disposed at positions overlapping with the image sensor 11 when viewed from the optical axis direction.

[0043] 2 and 3, a first ball 44a, a second ball 44b, and a third ball 44c are provided between the fixed part 20a and the movable part 20b. When the movable part 20b operates, the first ball 44a, the second ball 44b, and the third ball 44c roll, allowing the movable part 20b to move smoothly on the plane 12c orthogonal to the optical axis relative to the fixed part 20a.

[0044] The fixed part 20a and the movable part 20b are combined to form a VCM (voice coil motor), a magnetic circuit for detection, and a magnetic circuit for biasing. These circuits will be described below.

[0045] First, the VCM (voice coil motor) will be explained.

[0046] In the fixed portion 20a, the first rear magnet group 23a and the first front magnet group 26a, which are arranged side by side in the optical axis direction, form a first driving magnetic circuit. Similarly, the second rear magnet group 23b and the second front magnet group 26b form a second driving magnetic circuit, and the third rear magnet group 23c and the third front magnet group 26c form a third driving magnetic circuit. The first driving magnetic circuit and the first coil 33a in the movable portion 20b form a VCM as a first actuator. The second driving magnetic circuit and the second coil 33b in the movable portion 20b form a VCM as a second actuator. The third driving magnetic circuit and the third coil 33c in the movable portion 20b form a VCM as a third actuator. A Lorentz force is generated in a direction perpendicular to the magnetic field generated in the optical axis direction by the first drive magnetic circuit and the current flowing through the first coil 33a, and the resultant direction of the Lorentz force changes depending on the direction of current flow through the first coil 33a. Similar Lorentz forces are generated by the second drive magnetic circuit and second coil 33b, and by the third drive magnetic circuit and third coil 33c. The first and second actuators generate forces (drive forces) approximately parallel to the Y direction, and the sum of these forces generates a translational force in the Y direction, while the difference between these forces generates a rotational force around the optical axis. Meanwhile, the third actuator generates a translational force in the X direction.

[0047] Next, the biasing magnetic circuit and the detecting magnetic circuit will be described with reference to FIGS.

[0048] Fig. 6 is an exploded perspective view of the biasing magnetic circuit and the detection magnetic circuit. Fig. 7(a) is a projection view of the detection magnetic circuit when the movable part 20b is positioned at the center of the movement, as viewed from the subject side in the optical axis direction. Fig. 7(b) is a cross-sectional view taken along the arrow AA in Fig. 7(a).

[0049] First, the biasing magnetic circuit will be described.

[0050] As shown in FIG. 6, the fixed part 20a has a detection magnet group 27, and the movable part 20b has a thrust yoke 40 at a position facing the detection magnet group 27. Regarding the first detection magnet group 27a, as shown in FIG. 7(b), magnetic flux from the first detection magnet group 27a flows through the thrust yoke 40, generating an attractive force between the first detection magnet group 27a and the thrust yoke 40. A similar attractive force is generated between the second detection magnet group 27b and the thrust yoke 40, and between the third detection magnet group 27c and the thrust yoke 40. In this way, the attractive force acting between the detection magnet group 27 of the fixed part 20a and the thrust yoke 40 of the movable part 20b biases the movable part 20b in the optical axis direction (Z direction) relative to the fixed part 20a.

[0051] Next, the detection magnetic circuit will be described.

[0052] 6, the thrust yoke 40, the first detection magnet group 27a, and the detection yoke 28, which are arranged side by side in the optical axis direction, form a first magnetic circuit for detection. Similarly, the thrust yoke 40, the second detection magnet group 27b, and the detection yoke 28 form a second magnetic circuit for detection, and the thrust yoke 40, the third detection magnet group 27c, and the detection yoke 28 form a third magnetic circuit for detection.

[0053] The first detector 35a is disposed opposite the first detection magnet group 27a (position detection magnets), the second detector 35b is disposed opposite the second detection magnet group 27b, and the third detector 35c is disposed opposite the third detection magnet group 27c. The thrust yoke 40 is disposed on the opposite side of the detector 35 from the detection magnet group 27 in the optical axis direction. When viewed from the optical axis direction, the thrust yoke 40 is disposed so as to cover the detector 35.

[0054] The first detection magnetic circuit and the first detector 35a will be described with reference to FIG. 7(b). The first detector 35a is disposed between the first detection magnet group 27a and the thrust yoke 40. Therefore, the first detector 35a performs position detection while the magnetic flux of the first detection magnet group 27a flows through the thrust yoke 40. Similarly, the second detector 35b performs position detection while the magnetic flux of the second detection magnet group 27b flows through the thrust yoke 40. Furthermore, the third detector 35c performs position detection while the magnetic flux of the third detection magnet group 27c flows through the thrust yoke 40. In this manner, the detector 35 performs position detection within the magnetic field formed by the detection magnet group 27 of the fixed part 20a and the thrust yoke 40 of the movable part 20b, thereby enabling highly accurate position detection. In this embodiment, the detection magnet group 27 is disposed in the fixed part 20a, and the detector 35 is disposed in the movable part 20b. When comparing the weights of the detection magnet group 27 and the detector 35, the detector 35 is lighter, and therefore the configuration in which the detector 35 is arranged on the movable part 20b can reduce the driving load on the movable part 20b compared to the configuration in which the detection magnet group 27 is arranged on the movable part 20b.

[0055] Next, the flow of magnetic flux in the detection unit when the movable part 20b is moved will be described with reference to Figures 7 and 8. Figure 8 is a projection view of the detection magnetic circuit when the movable part 20b is positioned at the vibration isolation control end, as viewed from the subject side in the optical axis direction. Figure 8(b) is a cross-sectional view taken along arrow BB in Figure 8(a).

[0056] Since the thrust yoke 40 and the detector 35 are provided on the movable part 20b, the thrust yoke 40 and the detector 35 move relative to the detection magnet group 27 as the movable part 20b moves.

[0057] 7(a), the region (entire movable range) that always includes the thrust yoke 40 even when the thrust yoke 40 moves is indicated by hatching as region 41, corresponding to the vibration isolation control range of the image stabilization unit 20. Region 41 is set in a relationship such that it covers the detection magnet group 27 (first detection magnet group 27a, second detection magnet group 27b, third detection magnet group 27c). This makes it possible for the thrust yoke 40 to cover the detection magnet group 27 over the entire vibration isolation control range.

[0058] 8(a) shows a case where the movable part 20b moves and the thrust yoke 40 moves from the movable center position 50 indicated by the dashed line to the vibration isolation control end position 51 indicated by the solid line. As shown in FIG. 8(a), even when the movable part 20b is at the vibration isolation control end position 51, the thrust yoke 40 covers the detection magnet group 27. Therefore, even in this state, as shown in FIG. 8(b), the magnetic flux from the first detection magnet group 27a flows through the thrust yoke 40, similar to the state when the movable part 20b is at the movable center position 50 (FIG. 7(b)). Furthermore, the magnetic flux from the second detection magnet group 27b and the third detection magnet group 27c also flows through the thrust yoke 40, similar to the magnetic flux from the first detection magnet group 27a.

[0059] In this way, throughout the entire vibration isolation control range, the thrust yoke 40 covers the detection magnet group 27. This allows the detector 35 to perform position detection within the magnetic field formed by the detection magnet group 27 and the thrust yoke 40, resulting in highly accurate position detection.

[0060] It should be noted that a configuration with a thrust yoke 40 can improve the position detection accuracy of the detector 35 because the magnetic field is more stable than a configuration without the thrust yoke 40, but the thrust yoke 40 is not essential for position detection by the detector 35.

[0061] Furthermore, although the thrust yoke 40 is used as both the biasing magnetic circuit and the detecting magnetic circuit in the above-described embodiment, it is also possible to use separate yokes for the biasing magnetic circuit and the detecting magnetic circuit.

[0062] Next, the heat dissipation path of the imaging element 11 will be described with reference to Figs. 9 and 10. Fig. 9 is an exploded perspective view of the components of the heat dissipation path of the imaging element 11. Fig. 10 is a projection view and a cross-sectional view in the optical axis direction of the components of the heat dissipation path of the imaging element 11. Fig. 10(a) shows the projection view, and Fig. 10(b) is a cross-sectional view taken along arrow CC shown in Fig. 10(a).

[0063] Heat generated by the imaging element 11 is transferred to the imaging element substrate 11b (second substrate) fixed by the die bonding process. The imaging element substrate 11b is a rigid substrate and has an area that partially overlaps with the imaging element holding member 31, and transfers heat to the imaging element holding member 31 by making surface contact in that area.

[0064] Magnesium die-cast, aluminum die-cast, or the like is used for the imaging element holding member 31. The imaging element holding member 31 transfers heat transferred from the imaging element board 11b to the connecting member 38 via the three fixing portions fixed by the screws 45.

[0065] An aluminum alloy or the like is used for the connecting member 38. A heat transfer member 39 is connected to the connecting member 38, and a support member 43 is connected to the heat transfer member 39.

[0066] As shown in FIG. 10(b), the support member 43 is connected to the base member 13c, and the connecting member 38 is movable relative to the support member 43. That is, one end of the heat transfer member 39 is connected to the connecting member 38 of the movable part 20b, and the other end is connected to the support member 43 of the fixed part 20a. For this reason, a flexible sheet member with a thickness of approximately 0.1 mm, such as a graphite sheet, is used for the heat transfer member 39 so as not to hinder the movement of the movable part 20b. The graphite sheet has a higher thermal conductivity than the connecting member 38, which allows the heat transfer member 39 to efficiently transfer heat from the connecting member 38 to the support member 43.

[0067] As a result, heat generated by the imaging element 11 and transferred from the imaging element holding member 31 to the connecting member 38 is transferred to the support member 43 via the heat transfer member 39. The heat transferred to the support member 43 is also transferred to the base member 13c, and is finally dissipated from the base member 13c to the outside air. An aluminum alloy or the like is used for the support member 43, and magnesium die-casting, aluminum die-casting, or the like is used for the base member 13c.

[0068] Next, the heat transfer path from the image pickup element 11 to the detector 35 will be described.

[0069] As described above, heat generated by the imaging element 11 is transferred to the connecting member 38 via the imaging element substrate 11b and the imaging element holding member 31. Because the connecting member 38 is connected not only to the heat-transfer member 39 but also to the detection FPC 36, part of the heat transferred to the connecting member 38 is transferred to the detection FPC 36, and part of that heat is further transferred to the detector 35. The detection FPC 36 is a flexible printed circuit board, and has thermal conductivity that is 1 / 100 or less of that of the imaging element holding member 31 and the connecting member 38. Therefore, the heat transferred from these components to the detection FPC 36 is kept small. Furthermore, the detection FPC 36 has a lower thermal conductivity than the imaging element substrate 11b (second substrate). This makes it possible to reduce the transfer of heat generated by the imaging element 11 to the detector 35 compared to when the detector 35 is mounted on the imaging element substrate 11b.

[0070] Although the thrust yoke 40 is also connected to the connecting member 38, the detection FPC 36 has a lower thermal conductivity than the thrust yoke 40. Therefore, heat transferred to the connecting member 38 is more easily transferred to the thrust yoke 40 than to the detection FPC 36, and the heat transferred to the detection FPC 36 is kept small. As a result, heat transfer to the detector 35 can also be suppressed.

[0071] Furthermore, the detection FPC 36 has a lower thermal conductivity than the heat-transfer member 39. Therefore, heat transferred from the imaging element 11 to the connecting member 38 is transferred more easily to the heat-transfer member 39 than to the detection FPC 36, and the amount of heat transferred to the detection FPC 36 is kept small. As a result, heat transfer to the detector 35 can also be kept small. Note that, as described above, the detector 35 is not in contact with any components other than the detection FPC 36, and therefore the heat transfer path from the imaging element 11 to the detector 35 is most efficient through the path via the imaging element substrate 11b, the imaging element holding member 31, the connecting member 38, and the detection FPC 36. Even along this path, the amount of heat transferred to the detection FPC 36 is kept small due to the relationship between the thermal conductivity of the detection FPC 36 and other components. It is also assumed that heat is transmitted from the imaging element 11 to the detector 35 via the air between the imaging element 11 and the detector 35. However, since air has an even lower thermal conductivity than the detection FPC 36, the above-mentioned path is the path for the greatest heat transmission. The detector 35 may be in contact with a member other than the detection FPC 36 as long as the member has a lower thermal conductivity than the detection FPC 36. In other words, it is sufficient that the detector 35 is not in contact with a member having a higher thermal conductivity than the detection FPC 36.

[0072] In this way, by suppressing heat transfer from the imaging element 11 to the detector 35, it is possible to suppress temperature changes in the detector 35 due to heat generation from the imaging element 11, thereby enabling highly accurate position detection by the detector 35.

[0073] In this embodiment, the imaging element holding member 31 and the connecting member 38 are separate members, but they may also be formed as an integrally formed movable member. Furthermore, the imaging element 11 and the imaging element substrate 11b may be collectively referred to as the imaging element. In that case, the heat transfer path from the imaging element to the detector 35 can be rephrased as the path via the movable part 20b and the detection FPC 36 being the path with the greatest heat transfer.

[0074] The present invention has been described in detail above based on its preferred embodiments, but the present invention is not limited to these specific embodiments, and various forms within the scope of the invention that do not deviate from the gist of the invention are also included in the present invention.

[0075] The disclosure of this embodiment includes the following configuration. (Configuration 1) An imaging device having a drive mechanism with a first unit and a second unit arranged to be movable relative to the first unit within a predetermined range in a plane, wherein the second unit comprises an imaging element having an imaging surface perpendicular to an optical axis, a movable member holding the imaging element, a first board attached to the movable member, and a position detection element arranged in a position overlapping with the imaging element when viewed from the direction of the optical axis and mounted on the first board, the first unit having a position detection magnet arranged in a position opposite the position detection element, the path along which heat generated by the imaging element is most effectively transmitted to the position detection element is through the movable member and the first board, and the first board has a lower thermal conductivity than the movable member. (Configuration 2) The imaging device according to configuration 1, wherein the movable member comprises an imaging element holding member that holds the imaging element, and a connecting member that is connected to the imaging element holding member. (Configuration 3) An imaging device according to configuration 2, further comprising a heat transfer member having a higher thermal conductivity than the first substrate, the heat transfer member having one end connected to the connecting member and the other end connected to the first unit. (Configuration 4) The imaging device according to configuration 3, wherein the heat transfer member has a higher thermal conductivity than the connecting member. (Configuration 5) An imaging device described in any one of configurations 1 to 4, characterized in that the imaging element is held on the movable member via a second substrate, and the first substrate has a lower thermal conductivity than the second substrate. (Configuration 6) An imaging device described in any one of configurations 1 to 5, characterized in that the movable part includes a magnetic member, the magnetic member is positioned opposite the position detection magnet in the direction of the optical axis, and the position detection element is positioned between the magnetic member and the position detection magnet. (Configuration 7) The imaging device according to configuration 6, wherein the magnetic member is connected to the movable member, and the first substrate has a lower thermal conductivity than the magnetic member. (Configuration 8) The imaging device according to configuration 6 or 7, wherein the magnetic member is disposed so as to cover the position detection element when viewed from the direction of the optical axis. (Configuration 9) The imaging device according to configuration 6 or 7, wherein the magnetic member covers the position detection magnet over the entire movable range of the movable part when viewed from the direction of the optical axis. (Configuration 10) An imaging device having a drive mechanism with a first unit and a second unit arranged to be movable relative to the first unit within a predetermined range in a plane, wherein the second unit comprises an imaging element having an imaging surface perpendicular to an optical axis, a movable member holding the imaging element, a first substrate attached to the movable member, and a position detection element mounted on the first substrate and arranged in a position overlapping with the imaging element when viewed from the direction of the optical axis, wherein the first unit has a position detection magnet arranged in a position opposite the position detection element, the first substrate has a lower thermal conductivity than the movable member, and the position detection element is not in contact with a member having a higher thermal conductivity than the first substrate. [Explanation of symbols]

[0076] 10. Imaging device 11 Image sensor 11b Image sensor board 20a Fixed part 20b Moving part 27 Detection magnet group 27a First detection magnet group 27b Second detection magnet group 27c Third detection magnet group 31 Image sensor holding member 35 detectors 35a First detector 35b Second detector 35c Third detector 36 Detector FPC 38 Connecting member 39 Heat transfer materials 40 Thrust Yoke 43 Support member

Claims

1. A first unit; a second unit disposed so as to be movable relative to the first unit within a predetermined range in a plane; An imaging device having a drive mechanism having The second unit comprises: an imaging element having an imaging surface perpendicular to the optical axis; a movable member that holds the imaging element; a first substrate attached to the movable member; a position detecting element disposed at a position overlapping with the image sensor when viewed from the optical axis direction and mounted on the first substrate; the first unit has a position detection magnet arranged at a position facing the position detection element, An imaging device characterized in that the path along which heat generated by the imaging element is most easily transmitted to the position detection element is through the movable member and the first substrate, and the first substrate has a lower thermal conductivity than the movable member.

2. 2. The imaging device according to claim 1, wherein the movable member comprises an imaging element holding member that holds the imaging element, and a connecting member that is connected to the imaging element holding member.

3. a heat transfer member having a higher thermal conductivity than the first substrate; 3. The imaging device according to claim 2, wherein one end of the heat transfer member is connected to the connecting member and the other end is connected to the first unit.

4. 4. The imaging device according to claim 3, wherein the heat transfer member has a higher thermal conductivity than the connecting member.

5. the imaging element is held by the movable member via a second substrate; 2. The imaging device according to claim 1, wherein the first substrate has a lower thermal conductivity than the second substrate.

6. the movable part includes a magnetic member, the magnetic member is disposed at a position facing the position detection magnet in the direction of the optical axis, 2. The imaging device according to claim 1, wherein the position detecting element is disposed between the magnetic member and the position detecting magnet.

7. 7. The imaging device according to claim 6, wherein the magnetic member is connected to the movable member, and the first substrate has a lower thermal conductivity than the magnetic member.

8. 7. The imaging device according to claim 6, wherein the magnetic member is disposed so as to cover the position detecting element when viewed from the direction of the optical axis.

9. 7. The imaging device according to claim 6, wherein the magnetic member covers the position detection magnet over the entire movable range of the movable part when viewed from the direction of the optical axis.

10. A first unit; a second unit disposed so as to be movable relative to the first unit within a predetermined range in a plane; An imaging device having a drive mechanism having The second unit comprises: an imaging element having an imaging surface perpendicular to the optical axis; a movable member that holds the imaging element; a first substrate attached to the movable member; a position detecting element disposed at a position overlapping with the image sensor when viewed from the optical axis direction and mounted on the first substrate; the first unit has a position detection magnet arranged at a position facing the position detection element, the first substrate has a lower thermal conductivity than the movable member; An imaging device, wherein the position detecting element is not in contact with a member having a higher thermal conductivity than the first substrate.

Images