Imaging unit and imaging device

Abstract

The present invention provides an imaging unit that can improve heat dissipation from the image sensor while suppressing a decrease in the driving performance of the image blur correction mechanism. [Solution] The imaging unit (40) includes an image sensor (11), a fixed part (20), a movable part (30) that holds the image sensor and is supported so as to be movable on a plane perpendicular to the optical axis relative to the fixed part, and a magnet (23) and a coil (32) that drive the movable part. The fixed part includes a first holding member (21) and a first heat dissipation member (25) that hold the magnet or coil. The movable part includes a second holding member (31) and a second heat dissipation member (36) that hold the image sensor. The first heat dissipation member has a first surface (25a) perpendicular to the optical axis, and the second heat dissipation member has a second surface (35a) perpendicular to the optical axis. The first surface and the second surface have opposing regions that face each other in the direction of the optical axis.

Description

Technical Field

[0001] The present disclosure relates to an imaging unit and an imaging apparatus.

Background Art

[0002] Patent Document 1 discloses an imaging unit that has a movable portion including a cooling element and a first heat dissipation member, and a fixed portion including a second heat dissipation member for dissipating heat of the movable portion, and dissipates heat of an imaging element to the fixed portion without physical contact.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration disclosed in Patent Document 1, since the cooling element is arranged in the movable portion, the weight of the movable portion increases, and the driving performance of an image blur correction mechanism deteriorates.

[0005] Accordingly, an object of the present invention is to provide an imaging unit capable of enhancing heat dissipation performance from an imaging element while suppressing deterioration in driving performance of an image blur correction mechanism.

Means for Solving the Problems

[0006] An imaging unit as one aspect of the present disclosure comprises an image sensor, a fixed portion, a movable portion that holds the image sensor and is supported so as to be movable relative to the fixed portion in a plane perpendicular to the optical axis, and a magnet and a coil that drive the movable portion, wherein the fixed portion comprises a first holding member and a first heat dissipation member that hold the magnet or the coil, and the movable portion comprises a second holding member and a second heat dissipation member that hold the image sensor, wherein the first heat dissipation member has a first plane perpendicular to the optical axis, and the second heat dissipation member has a second plane perpendicular to the optical axis, and the first plane and the second plane have opposing regions that face each other in the direction of the optical axis. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an imaging unit that can improve heat dissipation from the image sensor while suppressing a decrease in the driving performance of the image blur correction mechanism. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the imaging system according to this embodiment. [Figure 2(A)] This is an exploded perspective view of the first image stabilization unit according to this embodiment. [Figure 2(B)] This is an exploded perspective view of the first image stabilization unit according to this embodiment, viewed from a different direction than Figure 2(A). [Figure 3(A)] This is an exploded perspective view of the fixed part according to this embodiment. [Figure 3(B)] This is an exploded perspective view of the fixed part according to this embodiment, seen from a different direction than Figure 3(A). [Figure 4(A)] This is an exploded perspective view of the movable part according to this embodiment. [Figure 4(B)] This is an exploded perspective view of the movable part according to this embodiment, seen from a different direction than Figure 4(A). [Figure 5(A)] This is a rear view of the first image stabilization unit according to this embodiment. [Figure 5(B)] This is a cross-sectional view of the first image stabilization unit according to this embodiment. [Figure 5(C)]This is a projection view showing the relationship between the fixed heat sink and the movable heat sink according to this embodiment. [Figure 6] This figure shows the relationship between the distance L and the temperature of the image sensor according to this embodiment. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described in detail below with reference to the drawings. In each drawing, the same reference numerals are used for the same components, and redundant descriptions are omitted.

[0010] First, the imaging system 10 according to this embodiment will be described with reference to Figure 1. Figure 1 is a schematic diagram of the imaging system 10 according to this embodiment. Note that some of the functional blocks shown in Figure 1 are realized by having a CPU or other computer (not shown) included in the imaging system 10 execute a computer program stored in memory (not shown) as a storage medium. However, this embodiment is not limited to this, and some or all of them may be realized in hardware. As hardware, dedicated circuits (ASICs) or processors (reconfigurable processors, DSPs) can be used. Also, each of the functional blocks shown in Figure 1 does not have to be built into the same housing, and may be configured by separate devices connected to each other via signal paths.

[0011] The imaging system 10 is, for example, a so-called mirrorless digital camera, and has a main unit (imaging device, camera body) 10a and a lens device (interchangeable lens) 10b that can be attached to or detached from the main unit 10a. However, this embodiment is not limited to this, and can also be applied to imaging devices in which the camera body and lens device are integrally configured.

[0012] The main body portion 10a includes an imaging element 11 having an imaging surface 11a, an imaging FPC (flexible printed circuit) 18 (see Fig. 2(b)), a base member 13c, and a main body side mount member 13a. The main body portion 10a further includes a camera control unit 14, a first blur correction control unit 15a, a first vibration detection unit 16a, an image processing unit 17, and a first blur correction unit (imaging unit) 40.

[0013] The lens device 10b includes an imaging optical system 12 including a blur correction lens 12b, a lens side mount member 13b, a second blur correction control unit 15b, a second vibration detection unit 16b, and a second blur correction unit 60.

[0014] In the present embodiment, a virtual representative light ray (in the direction perpendicular to the imaging surface 11a) of the light flux irradiated onto the imaging surface 11a of the imaging element 11 via the imaging optical system 12 is referred to as an optical axis 12a, and a plane orthogonal to the optical axis 12a (a plane perpendicular to the optical axis 12a) is referred to as an optical axis orthogonal plane 12c. The optical axis 12a passes through the center of the imaging surface 11a and is orthogonal to the imaging surface 11a. Further, in order to clarify the arrangement and positional relationship of each part constituting the imaging system 10 within the imaging system 10, as shown in Fig. 1, an X direction, a Y direction, and a Z direction that are orthogonal to each other are defined. The Z direction is a direction parallel to the optical axis 12a, the X direction is the width direction (lateral direction) of the imaging system 10, and the Y direction is the height direction (longitudinal direction) of the imaging system 10. The optical axis orthogonal plane 12c is an XY plane.

[0015] The imaging element 11 is configured by a photoelectric conversion element such as a CMOS image sensor or a CCD image sensor, and is arranged with the imaging surface 11a facing the subject side (the lens device 10b side) such that the imaging surface 11a is orthogonal to the optical axis 12a. The imaging element 11 generates an image signal by photoelectrically converting the 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 transmitted to the image processing unit 17 via the unillustrated imaging FPC 18, is subjected to various processes to be converted into image data, and is stored in an unillustrated memory (storage device).

[0016] The camera control unit 14 is an arithmetic unit in a main IC (not shown), receives input operations from the user via an operation unit (not shown), and controls the overall operation of the imaging system 10. The camera control unit 14 incorporates a CPU as a computer, and controls each unit of the imaging system 10 by executing a computer program stored in a memory (not shown).

[0017] The imaging optical system 12 is composed of a lens group (not shown) disposed inside the lens device 10b, and forms an image of light from a subject (not shown) on the imaging surface 11a of the imaging element 11. In the imaging system 10, in order to arrange 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 portion 10a, and the lens device 10b is also connected to the base member 13c.

[0018] The imaging element 11 is attached to the base member 13c via the first blur correction unit 40. The lens device 10b is connected to the base member 13c via the lens-side mount member 13b and the main body portion-side mount member 13a.

[0019] The first blur correction unit 40 moves the imaging element 11 in the XY directions or rotates it within the XY plane, thereby correcting image blur caused by shake generated in the imaging system 10 and making it possible to obtain a clear subject image. Specifically, when the posture of the imaging system 10 changes relative to the subject during imaging, the imaging position of the subject light flux on the imaging surface 11a of the imaging element 11 changes, which causes blur in the image obtained through the imaging element 11.

[0020] At that time, if the posture change of the imaging system 10 is sufficiently small, the change in the imaging position is uniform within the imaging surface 11a, and can be regarded as translational or rotational movement (image plane blur) within the XY plane. Therefore, by translating or rotationally moving the imaging element 11 within the XY plane so as to cancel out this image plane blur, a clear subject image with corrected image blur can be obtained.

[0021] Similarly, the second image stabilization unit 60 corrects image blur caused by vibrations in the imaging system 10 by moving the image stabilization lens 12b in the XY direction, thereby enabling the acquisition of a clear subject image. In other words, by moving the image stabilization lens 12b in the XY plane direction, the light beam from the subject is refracted. At this time, the image stabilization lens 12b is moved in the XY plane direction so as to cancel out image plane blur. As a result, a clear subject image with corrected image blur can be obtained. Note that the principle of image stabilization by moving the image sensor 11 and the image stabilization lens 12b is well known, so a more detailed explanation is omitted. Note that the image stabilization lens 12b may also be configured to move in the Z direction when it moves in the XY plane direction.

[0022] The first image stabilization unit 40 includes, for example, a fixed part, a movable part, and a plurality of driving force generating parts. The fixed part is fixed to the base member 13c, and the movable part holds the image sensor 11. The movable part is supported by the fixed part with three degrees of freedom and can be moved in the XY direction relative to the fixed part or rotated in the XY plane. In other words, the first image stabilization unit 40 is configured as a drive device (a so-called XYθ stage) capable of three-axis drive control, and is capable of moving the image sensor 11 in the XY direction and rotating it in the XY plane.

[0023] The second image stabilization unit 60 includes, for example, a fixed part, a movable part, and a plurality of driving force generating parts. The fixed part is fixed to a housing (not shown) of the lens device 10b, and the movable part holds the image stabilization lens 12b. The movable part is supported by the fixed part with two degrees of freedom and can move in the XY direction relative to the fixed part. In other words, the second image stabilization unit 60 is configured as a drive device (a so-called XY stage) capable of two-axis drive control, and is capable of moving the image stabilization lens 12b in the XY direction.

[0024] The first vibration detection unit 16a and the second vibration detection unit 16b are each composed of a gyro sensor or an acceleration sensor, and are vibration detection units that detect the angular velocity and acceleration of the imaging system 10 in each direction as vibration information of the imaging system 10.

[0025] The first image stabilization control unit 15a and the second image stabilization control unit 15b each calculate the amount of angular change and movement of the imaging system 10 in each direction as image stabilization information by integrating the angular velocity and acceleration detected by the first vibration detection unit 16a and the second vibration detection unit 16b, respectively.

[0026] Furthermore, the first image stabilization control unit 15a calculates a target movement value for the image sensor 11 based on the shake information detected by the first vibration detection unit 16a and controls the drive of the first image stabilization unit 40 to control the movement of the image sensor 11. Similarly, the second image stabilization control unit 15b calculates a target movement value for the image stabilization lens 12b based on the shake information detected by the second vibration detection unit 16b and controls the drive of the second image stabilization unit 60 to control the movement of the image stabilization lens 12b. Note that the imaging system 10 may be configured without the second image stabilization unit 60.

[0027] If the second image stabilization unit 60 is not provided, the image stabilization lens 12b is basically unnecessary. In that case, the imaging optical system 12 of the lens device 10b is designed so that the desired optical characteristics can be obtained with a lens configuration that does not include the image stabilization lens 12b.

[0028] Next, the detailed configuration of the first image stabilization unit 40 will be described with reference to Figures 2(A) and 2(B). Note that the configuration of the second image stabilization unit 60 is publicly known, and therefore its description will be omitted. Figure 2(A) is an exploded perspective view of the first image stabilization unit 40 included in the imaging system 10 according to this embodiment. Figure 2(B) is an exploded perspective view of the first image stabilization unit 40 viewed from a different direction than that shown in Figure 2(A).

[0029] The first image stabilization unit 40 is composed of a fixed part 20, a movable part 30, and balls 41a to 41c. The fixed part 20 is composed of a front fixed part 20a and a rear fixed part 20b. The first image stabilization unit 40 is arranged in the order of front fixed part 20a, movable part 30, and rear fixed part 20b in the Z direction, in order of proximity to the main body side mounting member 13a.

[0030] Next, the fixing portion 20 of the first image stabilization unit 40 will be described with reference to Figures 3(A) and 3(B). Figure 3(A) is an exploded perspective view of the fixing portion 20. Figure 3(B) is an exploded perspective view of the fixing portion 20 viewed from a different direction than that of Figure 3(A).

[0031] The rear fixing section 20b includes a base plate (fixing frame, first holding member) 21, a first rear yoke 22a, a second rear yoke 22b, a first magnet group 23a, a second magnet group 23b, a third magnet group 23c, a thrust magnet 24, and a fixing section heat sink 25. Here, the base plate 21 functions as a fixing member disposed inside the main body 10a of the imaging system 10. The base plate 21 has an opening (first opening) 21a and is made of a non-magnetic material.

[0032] The first magnet group 23a, the second magnet group 23b, and the third magnet group 23c are each fixed to the first rear yoke 22a or the second rear yoke 22b with adhesive or the like. The first rear yoke 22a and the second rear yoke 22b are each made of a magnetic material. The first rear yoke 22a and the second rear yoke 22b are fixed to the base plate 21 with screws or the like. In other words, the first magnet group 23a, the second magnet group 23b, and the third magnet group 23c are held by the base plate 21.

[0033] The thrust magnet 24 is fixed to the base plate 21 with adhesive or the like.

[0034] The fixed heat sink (first heat dissipation member) 25 has a flat portion (first surface) 25a parallel to the XY plane, and the flat portion 25a is positioned within the opening 21a of the base plate 21. The fixed heat sink 25 has fixing surfaces (first contact surfaces) 25b and 25c that contact the base plate 21 and is fixed with screws or the like. The fixed heat sink 25 has bent portions 25d and 25e between the flat portion 25a and the fixing portions 25b and 25c, respectively, which are perpendicular to the flat portion 25a. Preferably, the bent portions 25d and 25e are bent at an angle greater than 0 degrees and 90 degrees or less relative to the flat portion 25a (the angle between each bent portion and the flat portion 25a is 90 degrees or more and less than 180 degrees, with respect to the intersection point of each bent portion and the flat portion 25a as the reference point). The flat portion 25a is configured to be closer to the flat portion (second surface) 36a of the movable heat sink (second heat sink member) 36, described later, relative to the fixed portions 25b and 25c. Furthermore, the flat portion 25a is positioned in the -Z direction relative to the opening (second opening) 31a of the movable member (second holding member) 31, described later, so as not to penetrate the opening (second opening) 31a in the optical axis direction.

[0035] At least the surface of the flat portion 25a facing the flat portion 36a is treated to improve thermal emissivity. Thermal emissivity is the ratio of the energy of light emitted by an object through thermal radiation (radiance) to the energy of light emitted by a black body at the same temperature (blackbody radiation), which is set to 1.

[0036] The front fixing section 20a includes a front yoke 26, a first support member 27a, a second support member 27b, and a third support member 27c. The front yoke 26 is fixed to the base plate 21 of the rear fixing section 20b via the first support member 27a, the second support member 27b, and the third support member 27c. The first support member 27a, the second support member 27b, and the third support member 27c are positioned to restrict the movement of the movable section 30, thereby restricting the movement of the movable section 30 in the XY plane to a predetermined range. Cushioning material such as rubber is provided at the contact points between the first support member 27a, the second support member 27b, and the third support member 27c and the movable section 30 to absorb the impact during contact, thereby preventing damage and reducing impact noise.

[0037] In this embodiment, the first magnet group 23a, the second magnet group 23b, and the third magnet group 23c are arranged side by side so that two magnets magnetized in the Z direction generate magnetic fields in opposite directions. However, this embodiment is not limited to this, and a single magnet magnetized at two poles may also be used.

[0038] The first rear yoke 22a and the front yoke 26 are arranged to sandwich the first magnet group 23a in the Z direction. The first magnet group 23a forms a first magnetic circuit passing through the first rear yoke 22a and the front yoke 26. The second rear yoke 22b and the front yoke 26 are arranged to sandwich the second magnet group 23b and the third magnet group 23c in the Z direction. Similar to the first magnet group 23a, the second magnet group 23b and the third magnet group 23c form a second magnetic circuit and a third magnetic circuit, respectively.

[0039] Next, the movable part 30 of the first image stabilization unit 40 will be described with reference to Figures 4(A) and 4(B). Figure 4(A) is an exploded perspective view of the movable part 30. Figure 4(B) is an exploded perspective view of the movable part 30 viewed from a different direction than that of Figure 4(A).

[0040] The movable part 30 includes an image sensor 11, a movable member (movable frame, second holding member) 31, a first coil 32a, a second coil 32b, a third coil 32c, a drive FPC 33, a thrust yoke 34, and a movable part heat sink 36. The movable part 30 also includes a first heat sink 37a, a second heat sink 37b, a third heat sink 37c, and a fourth heat sink 37d.

[0041] The image sensor 11 is roughly rectangular in shape and is fixed to the movable member 31 with screws or the like.

[0042] The movable member 31 holds the image sensor 11 and is movable in the XY plane relative to the base plate 21, which acts as a fixed member. The movable member 31 has an opening 31a for attaching the imaging FPC 18 to the image sensor 11. The first coil 32a, the second coil 32b, and the third coil 32c are held by the movable member 31 and are positioned opposite the first magnet group 23a, the second magnet group 23b, and the third magnet group 23c, respectively.

[0043] The drive FPC 33 is positioned on the XY projection plane so as to overlap with the first coil 32a, the second coil 32b, and the third coil 32c, and is fixed to the movable member 31 with adhesive or the like.

[0044] The first magnetic circuit and the first coil 32a form a voice coil motor (VCM) as the first actuator. Similarly, the second magnetic circuit and the second coil 32b form a VCM as the second actuator, and the third magnetic circuit and the third coil 32c form a VCM as the third actuator.

[0045] A Lorentz force is generated in the first magnetic circuit in a direction perpendicular to the magnetic field generated in the Z direction and the current flowing through the first coil 32a, and the direction of the resultant Lorentz force changes depending on the direction of current flow through the first coil 32a. Similar Lorentz forces are generated in the second magnetic circuit and the second coil 32b, and in the third magnetic circuit and the third coil 32c.

[0046] The first actuator generates a translational force in the X direction. The second and third actuators generate forces (driving 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. The drive FPC 33 is fitted with a first detection element 33a, a second detection element 33b, and a third detection element 33c.

[0047] The first detection element 33a is located inside the first coil 32a, the second detection element 33b is located inside the second coil 32b, and the third detection element 33c is located inside the third coil 32c.

[0048] The first detection element 33a, the second detection element 33b, and the third detection element 33c are, for example, Hall elements. The first detection element 33a detects the magnetic force of the first magnetic circuit, and based on the result, the first blur correction control unit 15a calculates the position information of the movable part 30 in the XY plane relative to the fixed part 20 (specifically, the position and angle around the optical axis). The same applies to the second detection element 33b and the third detection element 33c.

[0049] The first coil 32a, the second coil 32b, and the third coil 32c are electrically connected to the drive FPC 33. The first image stabilization control unit 15a controls the current flowing to each coil via the drive FPC 33. Specifically, the first image stabilization control unit 15a calculates the deviation between the target movement value of the image sensor 11 based on the blur information detected by the first vibration detection unit 16a and the current position of the image sensor 11 detected by the first detection element 33a, the second detection element 33b, and the third detection element 33c. The first image stabilization control unit 15a then controls the drive of the movable part 30 by feedback control based on this deviation.

[0050] The movable part 30 is supported by the base plate 21 via rolling members, which are balls 41a to 41c, so that it can move in the XY plane. The balls 41a to 41c are arranged inside the first enclosure 31b, the second enclosure 31c, and the third enclosure 31d provided on the movable member 31, respectively. That is, the multiple balls 41a to 41c, which act as rolling members, are arranged to contact the movable member 31 and the base plate 21, which acts as a fixed member. When the movable part 30 moves in the XY plane relative to the fixed part 20, the balls 41a to 41c roll, so the frictional load between the movable member 31 and the base plate 21 is minimal.

[0051] The thrust yoke 34 is positioned opposite the thrust magnet 24 and is fixed to the movable member 31. The thrust magnet 24 forms a fourth magnetic circuit that passes through the thrust yoke 34. The movable member 31 is biased toward the base plate 21 in the -Z direction by the attractive force generated between the thrust magnet 24 and the thrust yoke 34. In other words, the thrust magnet 24 and the thrust yoke 34 constitute a first biasing unit that biases the movable part 30 toward the fixed part 20 in the -Z direction.

[0052] The movable part 30 also has a first thrust sheet metal 35a and a second thrust sheet metal 35b. The first thrust sheet metal 35a is positioned opposite the first magnet group 23a, and the second thrust sheet metal 35b is positioned opposite the third magnet group 23c, and they are fixed to the drive FPC 33 with adhesive or the like.

[0053] The first thrust sheet metal 35a and the second thrust sheet metal 35b are made of a magnetic material. That is, the first thrust sheet metal 35a and the second thrust sheet metal 35b are held by the movable member 31 and function as yoke members positioned opposite the first magnet group 23a and the third magnet group 23c, respectively.

[0054] The first thrust sheet metal 35a and the second thrust sheet metal 35b generate an attractive force between themselves and the opposing first magnet group 23a and third magnet group 23c, respectively. The first thrust sheet metal 35a and the second thrust sheet metal 35b constitute a second biasing section and a third biasing section, respectively, for biasing the movable member 31 toward the base plate 21, which acts as a fixed member, in the -Z direction. In other words, the first thrust sheet metal 35a and the second thrust sheet metal 35b, acting as yoke members, bias the movable part 30 toward the fixed part 20 in the -Z direction.

[0055] The first biasing part, the second biasing part, and the third biasing part are arranged in the XY plane such that the center of gravity of the movable part 30 is located inside the triangle formed by connecting each biasing part. The arrangement of the balls 41a to 41c is the same. As a result, a balanced biasing force can be generated on the movable part 30. Therefore, it is possible to prevent the movable part 30 from lifting up during operation.

[0056] The movable heat sink (second heat sink) 36 has a flat portion 36a parallel to the XY plane, and the flat portion 36a is positioned opposite the flat portion 25a of the fixed heat sink 25. The movable heat sink 36 is fixed to the movable member 31 by its fixed surfaces (second contact surfaces) 36b and 36c, which are in contact with the movable member 31, and is secured with screws or the like. The flat portion 36a and the fixed portions 36b and 36c are arranged on substantially the same plane.

[0057] At least the surface of the flat portion 36a facing the flat portion 25a of the fixed heat sink 25 is surface-treated to improve thermal emissivity. The movable heat sink 36 is positioned so that it partially overlaps with the image sensor 11 on the XY projection plane. That is, the image sensor 11, the movable heat sink 36, and the fixed heat sink 25 are positioned so that at least a portion of them overlaps on the XY projection plane (the image sensor 11, the movable heat sink 36, and the fixed heat sink 25 have regions that overlap each other when viewed from the direction of the optical axis).

[0058] Here, the flat portion 36a of the movable heat sink 36 and the flat portion 25a of the fixed heat sink 25 are positioned so as not to overlap with the first actuator, the second actuator, and the third actuator in the XY projection area, but to overlap in the Z direction.

[0059] The first heat dissipation sheet 37a, the second heat dissipation sheet 37b, the third heat dissipation sheet 37c, and the fourth heat dissipation sheet 37d are each heat conductive members with one end attached to the four sides of the image sensor 11. The other end of each of the first heat dissipation sheet 37a, the second heat dissipation sheet 37b, the third heat dissipation sheet 37c, and the fourth heat dissipation sheet 37d is connected to the movable member 31 and the movable part heat dissipation plate 36. That is, the movable part heat dissipation plate 36 is connected to the image sensor 11 via each heat dissipation sheet. The first heat dissipation sheet 37a, the second heat dissipation sheet 37b, the third heat dissipation sheet 37c, and the fourth heat dissipation sheet 37d are, for example, graphite sheets.

[0060] Next, the heat dissipation path of the image sensor 11 of the first image stabilization unit 40 will be described with reference to Figures 5(A) to 5(C). Figure 5(A) is a rear view of the first image stabilization unit 40. Figure 5(B) is a cross-sectional view of the first image stabilization unit 40 cut across plane AA in Figure 5(A). Figure 5(C) is a projection view showing the relationship between the fixed heat sink 25 and the movable heat sink 36, and is a view of only the fixed heat sink 25 and the movable heat sink 36 from Figure 5(A).

[0061] The heat generated when the image sensor 11 is driven is transferred to the first heat dissipation sheet 37a connected to the image sensor 11. The first heat dissipation sheet 37a then transfers heat to the movable part heat dissipation plate 36. The same applies to the second heat dissipation sheet 37b, the third heat dissipation sheet 37c, and the fourth heat dissipation sheet 37d.

[0062] Here, the first to fourth heat dissipation sheets 37a to 37d are each connected to the four sides of the roughly rectangular image sensor 11, thus suppressing temperature variations within the image sensor 11. Furthermore, the movable heat sink 36 is positioned in a location that overlaps with the image sensor 11 on the XY projection area. As a result, the distance from the image sensor 11 to the movable heat sink 36 for the first to fourth heat dissipation sheets 37a to 37d can be shortened, allowing heat from the image sensor 11 to be efficiently transferred to the movable heat sink 36.

[0063] Furthermore, the heat dissipation sheet connecting the image sensor 11 and the movable heat sink 36 is not limited to being connected only to the four sides of the image sensor 11, but may also be positioned approximately in the center. Alternatively, it may be connected to at least two opposing sides of the four sides of the image sensor 11.

[0064] The heat from the image sensor 11 transferred to the movable heat sink 36 is transferred via air from the flat portion 36a of the movable heat sink 36 to the flat portion 25a of the opposing fixed heat sink 25. Here, L is the distance in the Z direction between the flat portion 25a and the flat portion 36a, and S is the overlapping area (area of ​​the opposing region) of the flat portions 25a and 36a on the XY projection plane. At this time, according to Fourier's law, the amount of heat conducted through the air between the flat portion 25a and the flat portion 36a is inversely proportional to the distance L and proportional to the area S. Therefore, heat dissipation can be improved by reducing the distance L. In this embodiment, it is preferable that the distance L is greater than 0 mm and 1 mm or less.

[0065] Figure 6 shows an example of the temperature of the image sensor 11 during video recording when the distance L is varied. In Figure 6, the horizontal axis represents the distance L (mm), and the vertical axis represents the temperature of the image sensor 11 (°C). As shown in Figure 6, when the distance L is 1 mm or less, the temperature of the image sensor 11 can be reduced more effectively.

[0066] As described above, the flat portion 36a of the movable heat sink 36 and the flat portion 25a of the fixed heat sink 25 are positioned so as not to overlap with the first actuator, second actuator, and third actuator on the XY projection plane, but to overlap with them in the Z direction. Therefore, the area S can be increased to improve heat dissipation without increasing the size of the first vibration correction unit 40.

[0067] As mentioned above, the smaller the distance L between the planar portion 25a and the planar portion 36a, and the larger the opposing area S, the better the heat dissipation. On the other hand, since the movable heat sink 36 is a movable part, it needs to be configured so as not to interfere with the fixed portion 20 when driven. If the planar portion 25a of the fixed heat sink 25 enters the opening 31a of the movable member 31, the planar portion 25a must be made smaller to avoid interference during driving, which reduces the overlapping area S of the planar portion 25a and the planar portion 36a on the XY projection plane, thus reducing heat dissipation. Therefore, in order to reduce the distance L while increasing the area S, the planar portion 25a is positioned in the -Z direction so as not to enter the opening 31a of the movable member 31 in the optical axis direction. That is, the planar portion 25a of the fixed heat sink 25 does not overlap with the opening 31a of the movable member 31 when viewed from a direction perpendicular to the optical axis 12a. Similarly, the flat portion 36a of the movable heat sink 36 does not overlap with the opening 21a of the base plate 21 when viewed from a direction perpendicular to the optical axis 12a.

[0068] Furthermore, in order to maintain heat dissipation even when the movable heat sink 36 moves in the XY plane due to the image blur correction mechanism, it is preferable that the change in area S when the movable heat sink 36 moves is small within the range in which the movable part 30 can move (the entire range of motion of the movable part 30). More preferably, the rate of change in area (area of ​​the opposing region) S when the movable heat sink 36 moves is 10% or less. That is, when the maximum area (maximum value of area S) within the entire range of motion of the movable part 30 is Smax and the minimum area (minimum value of area S) is Smin, it is preferable that the following condition (1) is satisfied.

[0069] Smax - Smin / Smax ≤ 0.1 …(1) Furthermore, it is preferable that the area S is maximized at the initial position of the movable part 30 (the position where the center of the imaging surface 11a and the optical axis 12a coincide, without image blur correction) so that the heat dissipation is highest when the image sensor 11 is in operation. Also, it is preferable that the change in area S is smaller in the range in which the movable part 30 moves during continuous shooting or video recording of the imaging system 10, compared to when the movable part 30 is at the edge of its movable range.

[0070] As mentioned above, the fixed heat sink 25 and the movable heat sink 36 are subjected to surface treatment to increase their thermal emissivity. As will be described later, in this embodiment, the material of the fixed heat sink 25 and the movable heat sink 36 is, for example, aluminum. Aluminum has high thermal conductivity, but its thermal emissivity is less than 0.50. Therefore, by applying anodizing treatment as a surface treatment to the flat portion 25a of the fixed heat sink 25 and the flat portion 36a of the movable heat sink 36, the thermal emissivity is increased to, for example, 0.50 or higher. In addition to anodizing, other surface treatments such as painting, plating, and blasting may also be used. Since a higher thermal emissivity can be expected to provide a higher heat dissipation effect, it is preferable to select and implement an appropriate treatment depending on the material to be surface treated. By performing surface treatment, it is possible to increase the radiant heat released from the movable heat sink 36 into the air and improve heat transfer to the fixed heat sink 25, thereby improving the heat dissipation performance of the movable part 30.

[0071] With the above configuration, heat from the image sensor 11 can be transferred from the movable heat sink 36 to the fixed heat sink 25 by heat conduction through the air and radiant heat, thereby improving the heat dissipation from the image sensor 11. In addition, the first heat sink 37a to the fourth heat sink 37d are also connected to the movable member 31. Therefore, by transferring heat from the image sensor 11 not only to the movable heat sink 36 but also to the movable member 31, the heat dissipation can be further improved.

[0072] In the first image stabilization unit 40, the direction in which the movable member 31 faces the base plate 21 and the direction in which the flat portion 36a of the movable heat sink 36 faces the flat portion 25a of the fixed heat sink 25 are both in the -Z direction and are substantially the same. Therefore, if the imaging system 10 falls or the first image stabilization unit 40 is subjected to an impact from the outside in the +Z direction greater than that of the first biasing portion, the second biasing portion, and the third biasing portion, the movable portion 30 will be displaced in the +Z direction to a position where it temporarily contacts the front fixed portion 20a. That is, the flat portion 36a of the movable heat sink 36 and the flat portion 25a of the fixed heat sink 25 will be displaced in a direction away from each other in the Z direction.

[0073] On the other hand, if the first vibration correction unit 40 is subjected to an impact from the outside in the -Z direction greater than that applied to the first biasing part to the third biasing part, the movable part 30 is in contact with the rear fixed part 20b via the balls 41a to 41c, so the position of the movable part 30 and the rear fixed part 20b in the Z direction does not change. In other words, the distance in the Z direction between the flat part 36a of the movable part heat sink 36 and the flat part 25a of the fixed part heat sink 25 does not change. Therefore, even if the distance L in the Z direction between the flat part 36a of the movable part heat sink 36 and the flat part 25a of the fixed part heat sink 25 is reduced to 1 mm or less to improve heat dissipation, it is possible to suppress contact and deformation between the movable part heat sink 36 and the fixed part heat sink 25 when an impact is applied from the outside in the Z direction.

[0074] Next, the materials of each component constituting the first image stabilization unit 40 will be described. The base plate 21 is preferably made of a highly rigid material, such as stainless steel, in order to suppress deformation and changes in the flange back when the imaging system 10 is subjected to a strong external impact such as dropping.

[0075] The movable member 31 is preferably made of a low-density material, such as a magnesium alloy or a resin such as plastic, in order to reduce the weight of the movable part 30 and improve the driving performance of the image blur correction mechanism. As described above regarding the heat dissipation path, the heat from the image sensor 11 is also dissipated to the movable member 31 via the first heat dissipation sheet 37a to the fourth heat dissipation sheet 37d, so a magnesium alloy with high thermal conductivity is more preferable.

[0076] The movable heat sink 36 is preferably made of a material with higher thermal conductivity than the movable member 31, such as aluminum, in order to improve heat dissipation. The fixed heat sink 25 is preferably made of a material with higher thermal conductivity than the base plate 21, such as aluminum or copper, in order to improve heat dissipation. By using the above materials, the heat dissipation of the image sensor 11 can be improved by the movable heat sink 36 and the fixed heat sink 25, which have high thermal conductivity. Furthermore, by constructing the movable member 31 from a material with a lower density than the movable heat sink 36, the overall weight of the movable part 30 can be reduced, and a decrease in the driving performance of the image blur correction mechanism can be suppressed.

[0077] Next, with reference to Figures 5(A) and 5(B), the change in the flange back of the first image stabilization unit 40 that occurs when the image sensor 11 generates heat will be explained.

[0078] The heat generated when the image sensor 11 is driven is effectively dissipated to the fixed heat sink 25 and the movable member 31 via the aforementioned heat dissipation path. As a result, the movable heat sink 36 and the movable member 31 that fixes it, and the fixed heat sink 25 and the base plate 21 that fixes it, all become hot. Here, as mentioned above, if the materials of each component are selected considering their respective functions, the fixed heat sink 25 and the base plate 21 will be made of different materials. In other words, materials with different coefficients of thermal expansion will be fixed together, and due to the so-called bimetallic effect, warping will occur in the base plate 21 and the fixed heat sink 25. When the base plate 21 warps and deforms, the position of the movable part 30 held by the balls 41a to 41c changes in the Z direction, and the flange back changes.

[0079] In this embodiment, in order to suppress changes in the flange back, bent portions 25d and 25e are provided between the flat portion 25a of the fixed portion heat sink 25 and the fixed portions 25b and 25c. By providing relatively easily deformable bent portions 25d and 25e, when the base plate 21 and the fixed portion heat sink 25 warp due to the bimetallic effect, the bent portions 25d and 25e actively bend or deform, mitigating the overall warping. Therefore, it is possible to suppress changes in the flange back when the image sensor 11 generates heat.

[0080] The above describes the change in flange back due to the bimetallic effect when the image sensor 11 heats up, and the bending portion of each heat sink to suppress the change in flange back. However, to suppress the change in flange back, it is necessary to ensure a sufficient bending height of the bending portion. Also, as mentioned above, it is preferable that the flat portion 25a of the fixed heat sink 25 does not penetrate the opening 31a in the optical axis direction. To achieve both, it is preferable that the fixed portions 25b and 25c of the fixed heat sink 25 are provided on the side of the fixed heat sink 25 that is farther from the movable member 31 in the thickness direction (optical axis direction) of the base plate 21. With this configuration, the bending portions 25d and 25e can secure a bending height equal to the thickness of the base plate 21. As a result, the space in the optical axis direction can be effectively utilized, and the thickness of the second blur correction unit 60 in the optical axis direction can be made relatively thin.

[0081] In this embodiment, the movable heat sink 36 is configured as a flat plate without a bend, but it may also be configured with a bend similar to that of the fixed heat sink 25. In this case, it is preferable that the bend is at an angle greater than 0 degrees and 90 degrees or less relative to the flat portion 36a. The movable member 31 is made of magnesium alloy or a resin such as plastic, and the movable heat sink 36 is made of aluminum. In other words, different materials are fixed together as one, and warping occurs in the movable member 31 and the movable heat sink 36 due to the so-called bimetallic effect. Therefore, by providing a bend in the movable heat sink 36, it is possible to further suppress the change in flange back when the image sensor 11 generates heat.

[0082] On the other hand, to improve heat dissipation, it is preferable to reduce the distance L between the flat portion 25a and the flat portion 36a. However, if the shape has a bent portion between the flat portion 36a and the fixed portions 36b and 36c, the tolerance between the flat portion 36a and the fixed portions 36b and 36c increases. Furthermore, the fixed portion heat sink 25 and the movable portion heat sink 36 are a movable portion and a fixed portion, respectively, and it is necessary to configure them so that they do not come into contact with each other, taking into account variations in the parts. For this reason, in this embodiment, the bending portion of the movable portion heat sink 36 is eliminated to reduce part tolerances, and heat dissipation is prioritized by making the distance L as small as possible.

[0083] In this embodiment, the planar portion 25a and the planar portion 36a have opposing regions that face each other in the optical axis direction. Preferably, the distance between the planar portion 25a and the planar portion 36a in the optical axis direction is greater than 0 mm and 1 mm or less. Also preferably, the fixed heat sink 25 and the movable heat sink 36 are adjacent to each other in the optical axis direction. Also preferably, the opposing regions of the planar portions 25a and 36a are located in the optical axis direction, either on the same side as one of the first contact surfaces (25b, 25c) and the second contact surfaces (36b, 36c), or between the first contact surface and the second contact surface.

[0084] According to this embodiment, it is possible to provide an imaging unit and imaging device that can improve heat dissipation from the image sensor while suppressing a decrease in the driving performance of the image blur correction mechanism.

[0085] Each embodiment disclosed includes the following configuration: (Composition 1) Image sensor and The fixing part, A movable part that holds the image sensor and is supported so as to be movable relative to the fixed part in a plane perpendicular to the optical axis, The movable part includes a magnet and a coil that drive the movable part, The fixing portion includes a first holding member and a first heat dissipation member that hold the magnet or the coil. The movable part includes a second holding member for holding the image sensor and a second heat dissipation member. The first heat dissipation member has a first surface perpendicular to the optical axis, The second heat dissipation member has a second surface perpendicular to the optical axis, The imaging unit is characterized in that the first surface and the second surface have opposing regions that face each other in the optical axis direction. (Configuration 2) The imaging unit according to configuration 1, characterized in that the distance between the first surface and the second surface in the optical axis direction is greater than 0 mm and less than or equal to 1 mm. (Composition 3) The imaging unit according to configuration 1 or 2, characterized in that the first heat dissipation member and the second heat dissipation member are adjacent to each other in the optical axis direction. (Composition 4) The imaging unit according to any one of configurations 1 to 3, characterized in that the first heat dissipation member is made of a material with a higher thermal conductivity than the first holding member. (Composition 5) The imaging unit according to any one of configurations 1 to 4, characterized in that the second heat dissipation member is made of a material with a higher thermal conductivity than the second holding member. (Composition 6) The movable part has a heat conductive member, The imaging unit according to any one of configurations 1 to 5, characterized in that the second heat dissipation member is connected to the image sensor via the heat conduction member. (Composition 7) The imaging unit according to configuration 6, characterized in that one end of the heat conductive member is connected to the center of the image sensor or to at least two opposing sides of the image sensor. (Composition 8) The imaging unit according to any one of configurations 1 to 7, characterized in that the image sensor, the first heat dissipation member, and the second heat dissipation member have regions that overlap each other when viewed from the direction of the optical axis. (Composition 9) The imaging unit according to any one of configurations 1 to 8, characterized in that the second holding member is made of a material with a lower density than the second heat dissipation member. (Composition 10) The imaging unit according to any one of configurations 1 to 9, characterized in that the orientation of the second holding member toward the first holding member and the orientation of the second surface of the second heat dissipation member toward the first surface of the first heat dissipation member are the same. (Composition 11) The imaging unit according to any one of configurations 1 to 10, characterized in that the first surface and the second surface have the opposing regions within the entire range of motion of the movable part. (Composition 12) When Smax is the maximum area and Smin is the minimum area of ​​the opposing region within the entire range of motion, Smax - Smin / Smax ≤ 0.1 The imaging unit according to configuration 11, characterized in that it satisfies the following conditional expression. (Composition 13) The imaging unit according to any one of configurations 1 to 12, characterized in that the first surface and the second surface are each subjected to a surface treatment to increase thermal emissivity. (Composition 14) The imaging unit according to configuration 13, characterized in that the thermal emissivity of the first surface and the second surface, respectively, is 0.50 or greater. (Composition 15) The first holding member has a first opening formed therein. The second holding member has a second opening formed therein. The first surface does not overlap with the second aperture when viewed from a direction perpendicular to the optical axis. The imaging unit according to any one of configurations 1 to 14, characterized in that the second surface does not overlap with the first aperture when viewed from the direction perpendicular to the optical axis. (Composition 16) The first heat dissipation member has a first contact surface that contacts the first holding member, The second heat dissipation member has a second contact surface that contacts the second holding member, The imaging unit according to any one of configurations 1 to 15, characterized in that a bent portion is provided between the first contact surface and the first surface, and between the second contact surface and the second surface. (Composition 17) The imaging unit according to configuration 16, characterized in that the bent portion is bent at an angle greater than 0 degrees and 90 degrees or less with respect to the first surface or the second surface. (Composition 18) The imaging unit according to configuration 16 or 17, characterized in that the opposing region is the same as one of the first contact surface and the second contact surface, or is located between the first contact surface and the second contact surface, in the optical axis direction. (Composition 19) The imaging unit according to any one of the configurations 16 to 18, characterized in that the first contact surface is the surface of the first heat dissipation member that is farther from the second heat dissipation member in the optical axis direction. (Composition 20) The imaging unit described in any one of configurations 1 to 19, An imaging apparatus characterized by having a control unit for controlling the imaging unit.

[0086] While preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments, and various modifications and changes are possible within the scope of its essence. [Explanation of Symbols]

[0087] 11 Image sensor 40. First image stabilization unit (imaging unit) 12a optical axis 20 Fixed part 30 Moving parts 21 Base plate (first retaining member) 23a First Magnet Group (Magnets) 23b Second Magnet Group (Magnets) 23c Third magnet group (magnets) 25 Fixed heat sink plate (first heat sink member) 25a Flat part (first side) 31 Movable member (second holding member) 32a First coil (coil) 32b Second coil (coil) 32c Third coil (coil) 36. Movable part heat sink (second heat sink) 35a Flat part (second surface)

Claims

1. Image sensor and The fixing part, A movable part that holds the image sensor and is supported so as to be movable relative to the fixed part in a plane perpendicular to the optical axis, The movable part includes a magnet and a coil that drive the movable part, The fixing portion includes a first holding member and a first heat dissipation member that hold the magnet or the coil. The movable part includes a second holding member for holding the image sensor and a second heat dissipation member. The first heat dissipation member has a first surface perpendicular to the optical axis, The second heat dissipation member has a second surface perpendicular to the optical axis, The imaging unit is characterized in that the first surface and the second surface have opposing regions that face each other in the optical axis direction.

2. The imaging unit according to claim 1, characterized in that the distance between the first surface and the second surface in the optical axis direction is greater than 0 mm and less than or equal to 1 mm.

3. The imaging unit according to claim 1, characterized in that the first heat dissipation member and the second heat dissipation member are adjacent to each other in the optical axis direction.

4. The imaging unit according to claim 1, characterized in that the first heat dissipation member is made of a material with a higher thermal conductivity than the first holding member.

5. The imaging unit according to claim 1, characterized in that the second heat dissipation member is made of a material with a higher thermal conductivity than the second holding member.

6. The movable part has a heat conductive member, The imaging unit according to claim 1, characterized in that the second heat dissipation member is connected to the image sensor via the heat conduction member.

7. The imaging unit according to claim 6, characterized in that one end of the heat conductive member is connected to the center of the image sensor or to at least two opposing sides of the image sensor.

8. The imaging unit according to claim 1, characterized in that the image sensor, the first heat dissipation member, and the second heat dissipation member have regions that overlap each other when viewed from the direction of the optical axis.

9. The imaging unit according to claim 1, characterized in that the second holding member is made of a material with a lower density than the second heat dissipation member.

10. The imaging unit according to claim 1, characterized in that the orientation of the second holding member toward the first holding member and the orientation of the second surface of the second heat dissipation member toward the first surface of the first heat dissipation member are the same.

11. The imaging unit according to claim 1, characterized in that the first surface and the second surface have the opposing regions within the entire range of motion of the movable part.

12. When the maximum area of ​​the opposing region within the entire movable range is Smax and the minimum area is Smin, Smax-Smin / Smax≦0.1 The imaging unit according to claim 11, characterized in that it satisfies the following conditional expression.

13. The imaging unit according to claim 1, characterized in that the first surface and the second surface are each subjected to a surface treatment to increase the thermal emissivity.

14. The imaging unit according to claim 13, characterized in that the thermal emissivity of the first surface and the second surface, respectively, is 0.50 or greater.

15. The first holding member has a first opening formed therein. The second holding member has a second opening formed therein. The first surface does not overlap with the second aperture when viewed from a direction perpendicular to the optical axis. The imaging unit according to claim 1, characterized in that the second surface does not overlap with the first aperture when viewed from the direction perpendicular to the optical axis.

16. The first heat dissipation member has a first contact surface that contacts the first holding member, The second heat dissipation member has a second contact surface that contacts the second holding member, The imaging unit according to claim 1, characterized in that a bent portion is provided between the first contact surface and the first surface, and between the second contact surface and the second surface.

17. The imaging unit according to claim 16, characterized in that the bent portion is bent at an angle greater than 0 degrees and 90 degrees or less with respect to the first surface or the second surface.

18. The imaging unit according to claim 16, characterized in that the opposing region is the same as one of the first contact surface and the second contact surface, or is located between the first contact surface and the second contact surface, in the optical axis direction.

19. The imaging unit according to claim 16, characterized in that the first contact surface is the surface of the first heat dissipation member that is farther from the second heat dissipation member in the optical axis direction.

20. An imaging unit according to any one of claims 1 to 19, An imaging apparatus characterized by having a control unit for controlling the imaging unit.

Images