Optical element driving device, camera module, and camera mounting device

Abstract

The invention provides an optical element driving device, a camera module and a camera mounting device, which can restrain reduction of inclination characteristics and deviation of an optical axis, and can enable an optical element to move in the optical axis direction in a stable posture. The optical element driving device includes: a base; a holder on which the optical element can be mounted; a plurality of support parts that are disposed at rotationally symmetrical positions on the outer peripheral surface of the holder and that support the holder so as to be movable in the optical axis direction with respect to the base; and a drive unit that moves the holder in the optical axis direction. The support portion has: a ball; a ball receiving section that supports the balls so as to be capable of rolling in the optical axis direction; and a biasing part that presses the ball toward the ball receiving part. In an optical axis orthogonal plane orthogonal to the optical axis direction, a second component orthogonal to the radial direction is larger than a first component parallel to the radial direction passing through the optical axis and the center of the ball.

Description

Technical Field

[0001] The present invention relates to an optical element driving device, a camera module, and a camera mounting device. Background Art

[0002] Generally, a small camera module is mounted in a camera mounting device such as a smartphone or a drone. A drone is an unmanned aircraft that can fly by remote operation or automatic control, and there is also a drone called a multi-rotor aircraft.

[0003] The camera module uses an optical element driving device that drives optical elements such as lenses. The optical element driving device has, for example, an autofocus function (hereinafter referred to as "AF function", AF: Auto Focus) that moves an optical element (for example, a lens) in the optical axis direction and automatically focuses on a subject to be photographed (for example, see Patent Document 1). In addition, there is also a device having an optical image stabilization function (hereinafter referred to as "OIS function", OIS: Optical Image Stabilization) that optically corrects jitter (vibration) generated during shooting and reduces image blur.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-197626 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In the camera module described in Patent Document 1, guide balls that support the lens barrel so as to be movable in the optical axis direction are disposed between the housing and the lens barrel. The housing and the lens barrel are held in a state of applying force to each other via the guide balls. When the housing and the lens barrel are formed of a resin material such as liquid crystal polymer, the housing or the lens barrel is deformed by the acting force, the tilt characteristics are reduced, or an optical axis shift may occur.

[0009] An object of the present invention is to provide an optical element driving device, a camera module, and a camera mounting device that can suppress a reduction in tilt characteristics and an optical axis shift and can move an optical element in the optical axis direction in a stable posture.

[0010] Means for Solving the Problems

[0011] The optical element driving device according to the present invention includes:

[0012] A base;

[0013] A cage that can mount an optical element;

[0014] A plurality of support portions, which are disposed at rotationally symmetric positions on the outer peripheral surface of the cage and support the cage so as to be movable relative to the base in the optical axis direction; and

[0015] A drive portion that moves the cage in the optical axis direction,

[0016] The support portion has:

[0017] Ball bearings;

[0018] A ball bearing receiving portion that supports the ball bearings so as to be rollable in the optical axis direction; and

[0019] A biasing portion that presses the ball bearings toward the ball bearing receiving portion,

[0020] Regarding the acting force of the biasing portion, in the optical axis orthogonal plane orthogonal to the optical axis direction, the second component orthogonal to the radial direction is larger than the first component parallel to the radial direction passing through the optical axis and the center of the ball bearings.

[0021] The camera module according to the present invention includes:

[0022] The above-described optical element driving device; and

[0023] A photographing portion that photographs a subject image using the optical element.

[0024] The camera mounting device according to the present invention is an information device or a conveying device and includes the above-described camera module.

[0025] Effects of the Invention

[0026] According to the present invention, it is possible to suppress a decrease in tilt characteristics and an offset of the optical axis, and the optical element can be moved in the optical axis direction in a stable posture. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1A 、 Figure 1B is a diagram showing a smartphone equipped with a camera module according to an embodiment of the present invention.

[0028] Figure 2 is an external perspective view of the camera module.

[0029] Figure 3 is an external perspective view of the optical element driving device.

[0030] Figure 4 is an exploded perspective view of the optical element driving device.

[0031] Figure 5 is a top view of the optical element driving device.

[0032] Figure 6 It is a top view showing a support part enlarged.

[0033] Figure 7 It is a schematic diagram showing the acting force of the support part.

[0034] Figure 8 It is a perspective view of the support part.

[0035] Figure 9 It is a view showing another example of the support part.

[0036] Figure 10A 、 Figure 10B It is a view showing an automobile which is a camera mounting device for mounting a vehicle-mounted camera module.

[0037] Symbol Explanation

[0038] 1: Optical element driving device

[0039] 2: Lens part

[0040] 11: Cage

[0041] 12: Base

[0042] 20: Driving part

[0043] 30: Support part

[0044] 31: Ball

[0045] 32: Ball receiving part

[0046] 33: Biasing part

[0047] 34: Spacer

[0048] 36, 37: Stopping part

[0049] 38: Retaining member

[0050] M: Smart phone

[0051] A: Camera module Detailed Description of the Invention

[0052] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

[0053] <Smart phone>

[0054] Figure 1A 、 Figure 1B It is a view showing a smart phone M (an example of a camera mounting device) which mounts a camera module A according to an embodiment of the present invention. Figure 1A It is a front view of the smart phone M,Figure 1B It is a rear view of the smartphone M.

[0055] The smartphone M has a dual camera composed of two rear cameras OC1 and OC2. In this embodiment, the camera module A is applied to the rear cameras OC1 and OC2.

[0056] <Camera module>

[0057] Figure 2 It is a perspective view of the appearance of the camera module A. In this embodiment, the orthogonal coordinate system (X, Y, Z) is used for description. The same orthogonal coordinate system (X, Y, Z) is also shown in the figures described later.

[0058] The camera module A, for example, when actually shooting with the smartphone M, is mounted in such a way that the X-axis direction is the up-down direction (or left-right direction), the Y-axis direction is the left-right direction (or up-down direction), and the Z-axis direction is the front-back direction. That is, the Z-axis direction is the optical axis direction. In the figure, the upper side (+Z side) is the light-receiving side in the optical axis direction, and the lower side (-Z side) is the imaging side in the optical axis direction. In addition, the X-axis direction and the Y-axis direction orthogonal to the Z-axis are called the "optical axis orthogonal directions", and the XY plane is called the "optical axis orthogonal plane". Furthermore, the optical axis direction may also be renamed as the optical path direction or the focus direction (the direction for adjusting the focus) according to the type of optical element. In addition, among all directions in the optical axis orthogonal plane, the direction passing through the optical axis is called the "radial direction".

[0059] The camera module A has an AF function and can automatically focus when shooting a subject. In addition, the camera module A may also be configured to have an anti-shake function (hereinafter referred to as the "OIS function", OIS: Optical Image Stabilization) to optically correct the shake (vibration) generated during shooting and be able to shoot an image without image blur.

[0060] As Figure 2 shown, the camera module A includes an optical element driving device 1, a lens unit 2, a shooting unit 3, etc. The optical element driving device 1 is a driving device that realizes the AF function. The lens unit 2, for example, houses lenses in a cylindrical lens barrel. The shooting unit 3 shoots the subject image formed by the lens unit 2. That is, the optical element driving device 1 is a so-called lens driving device that drives the lens unit 2 as an optical element.

[0061] The optical element driving device 1 of this embodiment is designed considering being mounted on the above-mentioned camera module A, etc., and has a structure in which the length in the Z-axis direction is shorter than the lengths in the X-axis direction and the Y-axis direction. That is, it is a structure that reduces the height along the Z-axis direction to a low height.

[0062] The photographing unit 3 is disposed on the imaging side in the Z-axis direction of the optical element driving device 1. The photographing unit 3 includes, for example, an image sensor substrate 301, a photographing element 302 mounted on the image sensor substrate 301, and a module control unit 303.

[0063] The image sensor substrate 301 is, for example, a flexible printed circuit board (FPC; Flexible printed circuits). The image sensor substrate 301 is configured to be able to send the photographing signal obtained by the photographing element 302 to a control device (not shown) of the smartphone M. The control device of the smartphone M includes an image processing unit (not shown) that processes the received photographing signal. The optical element driving device 1 is mounted on the image sensor substrate 301 and is mechanically and electrically connected to the image sensor substrate 301.

[0064] The photographing element 302 is constituted by, for example, a CCD (charge-coupled device) type image sensor, a CMOS (complementary metal oxide semiconductor) type image sensor, etc., and photographs the subject image imaged by the lens unit 2.

[0065] The module control unit 303 is constituted by, for example, a control IC. The module control unit 303 performs drive control of the optical element driving device 1. The module control unit 303 may be provided on the image sensor substrate 301 or may be provided on a camera mounting device (in this embodiment, the smartphone M) that mounts the camera module A.

[0066] <Optical Element Driving Device>

[0067] Figure 3 is an external perspective view of the optical element driving device 1. Figure 4 is an exploded perspective view of the optical element driving device 1 viewed from the light-receiving side in the optical axis direction. Figure 5 is a top view of the optical element driving device 1 viewed from the light-receiving side in the optical axis direction. In Figure 3 the state where the lid 13 is removed is shown. In Figure 4 the lid 13 is omitted from the illustration.

[0068] As Figures 3 - 5 shown, the optical element driving device 1 includes a holder 11, a base 12, a lid 13, a driving unit 20, a support unit 30, etc.

[0069] The lid 13 is an exterior body of the optical element driving device 1. The lid 13 covers the outside of the driving device main body (reference numeral omitted). The lid 13 is a covered square cylinder having a substantially rectangular shape when viewed from above in the positive Z-axis direction (light-receiving side in the optical axis direction). The top view shape of the lid 13 is, for example, a square. That is, the optical element driving device 1 has a rectangular shape extending in the X-axis direction and the Y-axis direction when viewed from above in the positive Z-axis direction. In the following description, "top view" means a top view observed from the positive Z-axis direction.

[0070] The lid 13 has a substantially circular opening 131 on the light-receiving side surface (upper surface) in the optical axis direction. The lens unit 2 (refer to Figure 2 ) faces the outside through the opening 131 of the lid 13. The lens unit 2 may also be configured to protrude toward the light-receiving side in the Z-axis direction from the opening of the lid 13. For example, the lid 13 is fixed to the base 12 of the optical element driving device 1 by adhesion.

[0071] In addition, the lid 13 may be formed of, for example, a magnetic material and has a shielding function of shielding the incidence of electromagnetic waves from the outside or the radiation of electromagnetic waves to the outside.

[0072] The cage 11 is configured to be able to mount the lens unit 2 (refer to Figure 2 ). The cage 11 is a movable body that holds the lens unit 2 and moves in the Z-axis direction during focusing. The cage 11 is connected to the base 12 via the support portion 30. The cage 11 is formed of, for example, polyarylate (PAR), a PAR alloy in which a variety of resin materials including PAR are mixed, a liquid crystal polymer, or the like.

[0073] The cage 11 has, for example, a substantially octagonal shape when viewed from above. Specifically, the cage 11 has short side portions corresponding to the four corners of the optical element driving device 1 and long side portions connecting the short side portions. In addition, the cage 11 has a cylindrical opening 111 at the central portion. For example, the lens unit 2 (refer to Figure 2 ) is fixed to the inner peripheral surface of the opening 111 by adhesion.

[0074] The base 12 is a fixed body that supports the cage 11 so as to be movable in the Z-axis direction. The base 12 has a rectangular shape when viewed from above and has a circular opening 121 formed at the center. In the camera module A, an image sensor substrate 301 on which the imaging element 302 is mounted is disposed on the negative Z-axis side (imaging side in the optical axis direction) of the base 12.

[0075] The base 12 is formed of, for example, polyarylate (PAR), a PAR alloy in which a variety of resin materials including PAR are mixed (for example, PAR / PC), or a molding material made of a liquid crystal polymer.

[0076] A wiring metal part (not shown) is embedded in the base 12, for example, by insert molding. The wiring metal part is electrically connected to the wiring pattern of the image sensor substrate 301.

[0077] The driving unit 20 is an actuator that moves the holder 11 relative to the base 12 in the optical axis direction. In the present embodiment, an actuator of the VCM (voice coil motor) type is applied to the driving unit 20. Specifically, the driving unit 20 includes a magnet 21 and a coil 22 that constitute the VCM.

[0078] In the present embodiment, the magnet 21 is mounted on the side of the holder 11 as a movable body, and the coil 22 is mounted on the side of the base 12 as a fixed body. That is, a moving magnet type VCM is adopted.

[0079] Specifically, the magnet 21 is composed of a two-sided two-pole magnet having a rectangular parallelepiped shape. The magnet 21 is embedded in recesses provided on two opposed side surfaces (two side surfaces corresponding to the long side portions) of the holder 11 in the X-axis direction, and is fixed, for example, by adhesion.

[0080] The coil 22 is a flat coil that is energized during focusing. The coil 22 is fixed so as to face the magnet 21. Specifically, two coils 22 are arranged on a coil substrate 23. The coil substrate 23 is a flexible printed circuit board having a wiring pattern (not shown) for supplying power to the coil 22. The wiring pattern of the coil substrate 23 is electrically connected to a wiring metal part (not shown) arranged on the base 12.

[0081] The coil substrate 23 is wound around a ball bearing portion 32 erected on the base 12 so that the magnet 21 and the coil 22 face each other in the X-axis direction, and is fixed to the base 12. The sizes or arrangements of the magnet 21 and the coil 22 are set such that the magnetic field radiating from the magnet 21 in the X-axis direction intersects the coil 22 and returns to the magnet 21.

[0082] In addition, the structure of the above-described driving unit 20 (for example, the number, shape, and arrangement of the magnet 21 and the coil 22, etc.) is an example, and other structures can also be applied. For example, in the case where the driving unit 20 is an actuator of the VCM type, a so-called moving coil type VCM in which the coil 22 is mounted on the side of the holder 11 and the magnet 21 is mounted on the side of the base 12 can also be adopted. In addition, for example, the driving unit 20 can also apply an actuator of the ultrasonic motor type.

[0083] The support portion 30 supports the cage 11 so as to be movable relative to the base 12 in the Z-axis direction (optical axis direction). A plurality of support portions 30 are arranged at rotationally symmetric positions on the outer peripheral surface of the cage 11. In the present embodiment, the support portions 30 are arranged at the four corner portions of the rectangular shape, that is, at positions symmetrically rotated by 90° about the optical axis. By arranging the support portions 30 at rotationally symmetric positions about the optical axis, the cage 11 is supported in a stable posture, and thus a decrease in tilt characteristics and an offset of the optical axis can be suppressed.

[0084] In addition, it is sufficient that the support portions 30 are arranged at a plurality of rotationally symmetric positions about the optical axis. For example, they may be arranged at three portions symmetrically rotated by 120°.

[0085] Each support portion 30 is configured to include a ball 31, a ball receiving portion 32, and a biasing portion 33. The ball 31 is a rolling element that can roll following the movement of the cage 11 in the Z-axis direction. The ball receiving portion 32 supports the ball 31 so as to be able to roll in the Z-axis direction. The biasing portion 33 presses the ball 31 toward the ball receiving portion 32.

[0086] In the present embodiment, each support portion 30 has a first ball support portion 30A and a second ball support portion 30B.

[0087] The ball receiving portion 32 is fixed to the base 12. The biasing portion 33 is fixed to the cage 11. In the present embodiment, the base 12 and the ball receiving portion 32 are integrally formed as one component. More specifically, two ball receiving portions 32 are erected at each of the four corner portions of the base 12. In addition, a biasing portion 33 is provided for each ball receiving portion 32. The ball 31 is received in the accommodation space formed by the ball receiving portion 32 and the biasing portion 33.

[0088] The biasing direction of the biasing portion 33 intersects the radial direction passing through the optical axis O and the center of the ball 31 in the XY plane (see Figure 6 ). Compared with the case where the biasing direction of the biasing portion 33 is the same as the radial direction, the acting force applied to the cage 11 via the ball 31 becomes smaller, and thus deformation of the cage 11 caused by the acting force can be suppressed.

[0089] Figure 6 is a top view showing an enlarged view of one support portion 30. Figure 7 is a schematic diagram showing the acting force of the support portion 30. Figure 8 is a perspective view of the support portion 30.

[0090] As Figures 6 - 8 shown, the first ball support portion 30A has a set of balls 31A, a ball receiving portion 32A, and a biasing portion 33A. Similarly, the second ball support portion 30B has a set of balls 31B, a ball receiving portion 32B, and a biasing portion 33B.

[0091] In an embodiment, a spacer 34A is interposed between two balls 31A, and a spacer 34B is interposed between two balls 31B. Further, the support portion 30 has stoppers 36 and 37.

[0092] The biasing direction of the biasing portion 33A intersects the radial direction D1 passing through the center of the ball 31A in the XY plane. When the acting force F1 of the biasing portion 33A is decomposed into a first component F11 parallel to the radial direction D1 and a second component F12 orthogonal to the radial direction, the second component F12 is larger than the first component F11. That is, the biasing direction of the biasing portion 33A is set such that F11 < F12.

[0093] Similarly, the biasing direction of the biasing portion 33B intersects the radial direction D2 passing through the center of the ball 31B in the XY plane. When the acting force F2 of the biasing portion 33B is decomposed into a first component F21 parallel to the radial direction D2 and a second component F22 orthogonal to the radial direction, the second component F22 is larger than the first component F21. That is, the biasing direction of the biasing portion 33B is set such that F21 < F22.

[0094] Further, the first ball support portion 30A and the second ball support portion 30B have a structure that is symmetric with respect to the radial direction D3 passing through the midpoint of the line segment connecting the centers of the balls 31A and 31B and the optical axis O. That is, the direction of the acting force F1 of the first ball support portion 30A is symmetric with respect to the radial direction D3 to the direction of the acting force F2 of the second ball support portion 30B. Further, the components of the acting forces F1 and F2 orthogonal to the radial direction D3 are in opposite directions.

[0095] Hereinafter, without distinguishing the structures of the first ball support portion 30A and the second ball support portion 30B, they are simply referred to as "ball 31", "ball receiving portion 32", "biasing portion 33", and "spacer 34".

[0096] The ball receiving portion 32 is a columnar body having a groove portion 321. The groove portion 321 extends in the Z-axis direction and, for example, has a V-shaped shape in a plan view. Specifically, the groove portion 321 of the ball receiving portion 32 has an L-shaped shape (an example of a V-shaped shape) in a plan view. The ball receiving portion 32 is arranged on the base 12 such that the two surfaces of the groove portion 321 are along the X-axis direction and the Y-axis direction, respectively.

[0097] The biasing portion 33 is a leaf spring formed of a plate-like body. The biasing portion 33 preferably has a groove portion 331. The groove portion 331 extends in the Z-axis direction and, for example, has a V-shaped shape in a plan view. Specifically, the groove portion 331 of the biasing portion 33 has an L-shaped shape (an example of a V-shaped shape) in a plan view. The biasing portion 33 is mounted on the cage 11 such that the two surfaces of the groove portion 331 are along the X-axis direction and the Y-axis direction, respectively.

[0098] In the present embodiment, the biasing portions 33A of the first ball support portion 30A and the biasing portions 33B of the second ball support portion 30B are integrally formed on one component. Specifically, the biasing portions 33A and 33B are part of a sheet metal component formed by bending a single sheet of plate, and are connected by a connecting portion 35 that is U-shaped when viewed from above. For example, the connecting portion 35 is fixed to the cage 11 by being bolted to the short side portion of the cage 11.

[0099] In the sheet metal component in which the biasing portions 33A and 33B are formed, the angular interval between the biasing portions 33A and 33B (for example, the angular interval between the vertices of the V-shaped groove portions 321 and 331) is set wider than in the state after the support portion 30 is assembled. That is, in the state after the support portion 30 is assembled, the biasing portions 33A and 33B apply a force in a direction in which they separate from each other.

[0100] Through the groove portion 321 of the ball receiving portion 32 and the groove portion 331 of the biasing portion 33, a receiving space having a substantially planar shape when viewed from above is formed. Two balls 31 and a spacer 34 are received in this receiving space. The balls 31 are held in a state of being biased by the groove portion 321 of the ball receiving portion 32 and the groove portion 331 of the biasing portion 33. In the present embodiment, the balls 31 are four-point supported by the V-shaped groove portion 321 and the V-shaped biasing portion 33.

[0101] In addition, the lengths of the two balls 31 and the spacer 34 in the Z-axis direction are smaller than the length of the receiving space formed by the ball receiving portion 32 and the biasing portion 33 in the Z-axis direction. That is, the balls 31 and the spacer 34 are received in the receiving space so as to be movable in the Z-axis direction.

[0102] The stopper portions 36 and 37 prevent the balls 31 from coming off in the optical axis direction. The stopper portions 36 and 37 are respectively provided so as to close the positive side in the Z-axis direction (the light-receiving side in the optical axis direction) and the negative side in the Z-axis direction (the imaging side in the optical axis direction) of the receiving space formed by the groove portion 321 of the ball receiving portion 32 and the groove portion 331 of the biasing portion 33. In the present embodiment, the stopper portions 36 and 37 are continuously provided at both ends of the biasing portion 33 in the Z-axis direction. In addition, the stopper portions 36 and 37 may be disposed as long as they are on the positive side (the light-receiving side in the optical axis direction) and the negative side (the imaging side in the optical axis direction) of the balls 31 in the Z-axis direction, and may not be disposed at both ends of the biasing portion 33 in the Z-axis direction.

[0103] The spacer 34 maintains a constant separation distance between the two balls 31. The spacer 34 has, for example, a columnar main body portion 341 and seat surface portions 342 disposed at both ends of the main body portion 341. The seat surface portions 342 come into contact with the balls 31. The spacer 34 moves together with the balls 31 when the balls 31 move in the optical axis direction.

[0104] The outer shape of the seat surface portion 342 is preferably smaller than the outer shape of the ball 31 when viewed from above. When the outer shape of the seat surface portion 342 is the same as the outer shape of the ball 31, the seat surface portion 342 contacts the ball receiving portion 32 in the same manner as the ball 31. On the other hand, when the outer shape of the seat surface portion 342 is small, the contact area between the seat surface portion 342 and the ball receiving portion 32 becomes smaller. Therefore, the frictional force between the seat surface portion 342 and the ball receiving portion 32 is reduced, and the ball 31 can move smoothly in the optical axis direction.

[0105] In addition, the outer shape of the main body portion 341 may be the same as the outer shape of the seat surface portion 342, or may be smaller than the outer shape of the seat surface portion 342. When the outer shape of the main body portion 341 is smaller than the outer shape of the seat surface portion 342, weight reduction and cost reduction of the components can be achieved.

[0106] When performing autofocus in the optical element driving device 1, the coil 22 is energized. Power is supplied to the coil 22 via the coil substrate 23. When the coil 22 is energized, due to the interaction between the magnetic field of the magnet 21 and the current flowing through the coil 22, the coil 22 generates a Lorentz force. The direction of the Lorentz force is a direction (Z-axis direction) orthogonal to the direction (X-axis direction) of the magnetic field generated by the magnet 21 and the direction (Y-axis direction) of the current flowing through the coil 22. Since the coil 22 is fixed, a reaction force acts on the magnet 21. This reaction force becomes the driving force of the voice coil motor, and the holder 11 provided with the magnet 21 moves in the optical axis direction to perform autofocus.

[0107] At this time, since the biasing portion 33 is fixed to the holder 11, the ball 31 mainly rolls as the holder 11 moves in the optical axis direction. The holder 11 can move in the optical axis direction in a stable posture through the support portion 30 using the ball 31. In addition, the ball 31 sometimes slides as the holder 11 moves in the optical axis direction.

[0108] [Modified Example]

[0109] Figure 7 It is a diagram showing another example of the support portion 30.

[0110] In the embodiment, in the support portion 30, two balls 31 are arranged in the accommodation space formed between the ball receiving portion 32 and the biasing portion 33, and the two balls 31 are separated by a spacer 34. In this case, depending on the posture of the optical element driving device 1, the balls 31 may move away from the spacer 34 and roll or slide in the accommodation space, and the separation distance between the two balls 31 may vary.

[0111] In contrast, in the modification, a holding member 38 is used instead of the spacer 34 to hold the two balls 31 in a separated state. The holding member 38 is a columnar member having ball receiving portions 381 that respectively receive the two balls 31. The ball receiving portions 381 are provided through the main body of the holding member 38 and receive the balls 31 in such a manner that the contact points of the biasing portions 33 are exposed. By using the holding member 38, in the receiving space formed by the ball receiving portion 32 and the biasing portion 33, the separation distance between the two balls 31 is always kept constant. As a result, the movement of the cage 11 in the optical axis direction is stable.

[0112] In addition, instead of the spacer 34 and the holding member 38, balls having a diameter smaller than that of the balls 31 may be interposed between the two balls 31 to maintain the separation distance between the two balls 31.

[0113] Thus, the optical element driving device 1, the camera module A, and the smartphone M (camera-equipped device) according to the present embodiment individually or in appropriate combination have the following characteristic features.

[0114] That is, the optical element driving device 1 includes: a base 12; a cage 11 that can mount a lens unit 2 (optical element); a plurality of support portions 30 that are arranged at rotationally symmetric positions on the outer peripheral surface of the cage 11 and support the cage 11 so as to be movable in the optical axis direction relative to the base 12; and a driving portion 20 that moves the cage 11 in the optical axis direction. The support portion 30 has: a ball 31; a ball receiving portion 32 that supports the ball 31 so as to be able to roll in the optical axis direction; and a biasing portion 33 that presses the ball 31 toward the ball receiving portion 32. Regarding the acting force F1 of the biasing portion 33A, in the optical axis orthogonal plane orthogonal to the optical axis direction, the second component F12 orthogonal to the radial direction D2 is greater than the first component F11 parallel to the radial direction D1 passing through the optical axis O and the center of the ball 31A. Similarly, regarding the acting force F2 of the biasing portion 33B, in the optical axis orthogonal plane orthogonal to the optical axis direction, the second component F22 orthogonal to the radial direction D2 is greater than the first component F21 parallel to the radial direction D2 passing through the optical axis O and the center of the ball 31B.

[0115] According to the optical element driving device 1, since the support portions 30 are arranged at rotationally symmetric positions centered on the optical axis, the cage 11 is supported in a stable posture, so that a decrease in tilt characteristics and an offset of the optical axis can be suppressed. In addition, compared with the case where the biasing direction of the biasing portion 33 is consistent with the radial direction, the acting forces (the first components F11 and F21 of the acting forces F1 and F2) acting on the cage 11 become smaller, so that deformation of the cage 11 caused by the acting forces can be suppressed. Therefore, the effect of suppressing a decrease in tilt characteristics and an offset of the optical axis is improved, and the lens unit 2 can be moved in the optical axis direction in a stable posture.

[0116] In the optical element driving device 1, the support portion 30 has a first ball support portion 30A and a second ball support portion 30B. The first ball support portion 30A and the second ball support portion 30B each have a set of balls 31, a ball receiving portion 32, and a biasing portion 33. The first ball support portion 30A and the second ball support portion 30B are radially symmetric about the midpoint between the two balls 31A, 31B and the optical axis O. The components of the acting forces F1, F2 of the biasing portions 33A, 33B that are orthogonal to the radial direction D3 are in opposite directions, and the force that causes the cage 11 to rotate about the optical axis is canceled out. Therefore, the posture of the cage 11 can be stabilized.

[0117] In the optical element driving device 1, the biasing portion 33A of the first ball support portion 30A and the biasing portion 33B of the second ball support portion 30B are integrally formed on one component. Thereby, the number of parts can be reduced, the assembly operation can be facilitated, and the acting forces of the biasing portions 33A, 33B can be easily controlled.

[0118] In the optical element driving device 1, the biasing portion 33 is constituted by a leaf spring. Thereby, the biasing portion 33 can be realized with a simple structure.

[0119] In the optical element driving device 1, the biasing portion 33 and the ball receiving portion 32 each have V-shaped groove portions 331, 321 and contact the ball 31 at two points. Thereby, the ball 31 can be held in a stable posture and can roll or slide smoothly in the optical axis direction.

[0120] In the optical element driving device 1, the biasing portion 33 is mounted on the cage 11, and the ball receiving portion 32 is mounted on the base 12. Thereby, the effect of suppressing the deformation of the cage 11 can be improved.

[0121] In the optical element driving device 1, the ball receiving portion 32 and the base 12 are integrally formed on one component. Thereby, the number of parts can be reduced and cost reduction can be achieved.

[0122] In the optical element driving device 1, the biasing portion 33 has stoppers 36, 37 that prevent the ball 31 from falling off in the optical axis direction. Thereby, the ball 31 can be reliably prevented from falling off, and the reliability of the optical element driving device 1 is improved.

[0123] In the optical element driving device 1, the support portion 30 has two balls 31 arranged in the optical axis direction and a spacer 34 interposed between the two balls 31. Since the two balls 31 and the spacer 34 can be respectively installed in the accommodation space formed by the ball receiving portion 32 and the biasing portion 33, various assembly methods can be applied, and the workability is improved.

[0124] In the optical element driving device 1, the spacer 34 has a columnar main body portion 341 and seat surface portions 342 disposed at both ends of the main body portion 341 and respectively contacting the two balls 31. Through the seat surface portions 342, the balls 31 can be held in a stable posture and the balls 31 can be rolled or slid.

[0125] In the optical element driving device 1, the outer shape of the seat surface portion 342 is smaller than the outer shape of the ball 31 when viewed from above in the optical axis direction. Since the friction between the seat surface portion 342 and the ball receiving portion 32 or the biasing portion 33 is reduced, the ball 31 can smoothly move in the optical axis direction.

[0126] In addition, in the optical element driving device 1 according to the modification, the support portion 30 has: two balls 31 arranged in the optical axis direction; and a holding member 38 having two ball receiving portions 381 respectively accommodating each of the two balls 31 in such a manner that the contact points with the biasing portion 33 are exposed. In the accommodation space formed by the ball receiving portion 32 and the biasing portion 33, the separation distance between the two balls 31 is always kept constant, so that the movement of the cage 11 in the optical axis direction is stable.

[0127] As described above, the invention completed by the present inventor has been specifically described based on the embodiments, but the present invention is not limited to the above embodiments and can be changed without departing from the gist thereof.

[0128] For example, in the above embodiment, the smartphone M is taken as an example for description, but the present invention can be applied to a camera mounting device having a camera module and an image processing unit that processes image information obtained by the camera module. The camera mounting device includes an information device and a transportation device. The information device includes, for example, a mobile phone with a camera, a notebook computer, a tablet terminal, a portable game machine, a web camera, a vehicle-mounted device with a camera (for example, a rear monitor device, a dash cam device), etc. In addition, the transportation device includes, for example, an automobile, a drone (unmanned aircraft), etc.

[0129] Figure 10A 、 Figure 10B FIG. is a view showing an automobile V as a camera mounting device equipped with a vehicle-mounted camera module VC (Vehicle Camera). Figure 10A is a front view of the automobile V, Figure 10B is a rear perspective view of the automobile V. The automobile V is equipped with the camera module A described in the above embodiment as the vehicle-mounted camera module VC. As Figure 10A 、 Figure 10BAs shown, the in-vehicle camera module VC is mounted on the front windshield facing forward, for example, or on the rear door facing rearward. The in-vehicle camera module VC is used for rear monitoring, dashcam, collision avoidance control, autonomous driving control, etc.

[0130] In addition, in the above-described embodiment, the optical element driving device 1 that drives the lens unit 2 as an optical element has been described. However, the optical element to be driven may be an optical element other than a lens, such as a mirror or a prism. In addition, the present invention can also be applied, for example, to an optical element driving device that drives an imaging element as an optical element.

[0131] In addition, in the above-described embodiment, the optical element driving device 1 has an AF function, but it may have not only an AF function but also a function such as a zoom function that moves the lens unit 2 in the Z-axis direction.

[0132] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is represented not by the above description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. An optical element driving device, characterized in that: have: Pedestal; a holder capable of mounting an optical element; a plurality of support portions arranged at rotationally symmetrical positions on the outer peripheral surface of the holder and supporting the holder so as to be movable relative to the base in the optical axis direction; as well as a driving unit that moves the holder along the optical axis direction, The support portion has: Ball bearings; A ball bearing portion, which supports the ball so that it can roll along the optical axis direction; as well as a force applying portion that presses the ball toward the ball receiving portion, Regarding the urging force of the urging portion, in an optical axis orthogonal plane orthogonal to the optical axis direction, a second component orthogonal to the radial direction is larger than a first component parallel to a radial direction passing through the optical axis and the center of the ball.

2. The optical element driving device according to claim 1, characterized in that: The support portion includes a first ball support portion and a second ball support portion. The first ball support portion and the second ball support portion each include a set of the balls, the ball receiving portion, and the force applying portion. The first ball support portion and the second ball support portion are symmetrical with respect to a radial direction passing through a midpoint between the two balls and the optical axis.

3. The optical element driving device according to claim 2, characterized in that: The urging portion of the first ball support portion and the urging portion of the second ball support portion are integrally formed in one member.

4. The optical element driving device according to claim 1 or 2, characterized in that: The urging portion is composed of a leaf spring.

5. The optical element driving device according to claim 4, characterized in that: The biasing portion and the ball receiving portion each have a V-shaped groove portion, and are in contact with the ball at two points.

6. The optical element driving device according to claim 1 or 2, characterized in that: The force applying portion is mounted on the retaining frame, The ball bearing portion is mounted on the base.

7. The optical element driving device according to claim 6, characterized in that: The ball receiving portion and the base are integrally formed in one member.

8. The optical element driving device according to claim 1 or 2, characterized in that: The support portion has a stopper portion for preventing the ball from falling off in the direction of the optical axis.

9. The optical element driving device according to claim 1 or 2, characterized in that: The support portion has: The two balls are arranged along the optical axis; and A spacer is disposed between the two balls.

10. The optical element driving device according to claim 9, characterized in that: The spacer has: a columnar main body; and The seat surface parts are arranged at both ends of the main body part and are in contact with the two balls respectively.

11. The optical element driving device according to claim 10, characterized in that: In a plan view viewed from the optical axis direction, an outer shape of the seat surface portion is smaller than an outer shape of the ball.

12. The optical element driving device according to claim 1 or 2, characterized in that: The support portion has: The two balls are arranged along the optical axis; and The retainer has two ball receiving portions, each of which receives the two balls in such a manner that a contact point with the biasing portion is exposed.

13. A camera module, characterized in that: have: The optical element driving device according to claim 1; and The imaging unit uses the optical element to capture an image of a subject.

14. A camera-mounted device, which is an information device or a transport device, characterized in that: A camera module according to claim 13 is provided.

Images