Rotational Drive Unit

Abstract

To provide a rotation drive device with which it is possible to reduce an influence of external magnetism and reduce the device size and height.SOLUTION: The rotation drive device comprises: a stationary unit; a ring-shaped rotor which is disposed on the stationary unit; a sliding unit that supports the sliding of the rotor with respect to the stationary unit; an ultrasonic motor which is fixed to the stationary unit on an outer circumferential side of the rotor and has a piezoelectric element and a resonance unit which are both tabular, with their planar surfaces pasted to each other; and a power transmission unit which is fixed to the rotor on the outer circumferential side of the rotor and connected to the resonance unit, and has a length in a circumferential direction of the rotor. The power transmission unit is moved in the circumferential direction by linear motion of the resonance unit that resonates to the vibration of the piezoelectric element, thereby causing the rotor to rotationally move.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a rotary drive device. [Background technology]

[0002] Generally, a small camera module is mounted on a mobile terminal such as a smartphone. A lens driving device having an autofocus function (hereinafter referred to as "AF function"; AF: Auto Focus) that automatically adjusts the focus when photographing a subject and an image stabilization function (hereinafter referred to as "OIS function"; OIS: Optical Image Stabilization) that optically corrects shake (vibration) that occurs during photographing to reduce image distortion is applied to such a camera module (for example, Patent Document 1).

[0003] The lens driving device having an AF function and an OIS function includes an autofocus driving unit (hereinafter referred to as an "AF driving unit") for moving the lens unit in the optical axis direction, and a shake correction driving unit (hereinafter referred to as an "OIS driving unit") for swinging the lens unit in a plane perpendicular to the optical axis direction. In Patent Document 1, a voice coil motor (VCM) is applied to the AF driving unit and the OIS driving unit.

[0004] In recent years, camera modules with multiple (typically two) lens drive devices (so-called dual cameras) have been put to practical use. Dual cameras have a variety of possibilities depending on the usage scenario, such as being able to simultaneously capture two images with different focal lengths, or being able to simultaneously capture a still image and a video image. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-210550 A [Patent Document 2] International Publication No. 2015 / 123787 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as in Patent Document 1, a lens driving device using a VCM is susceptible to external magnetism, and there is a risk that high-precision operation may be impaired. In particular, in a dual camera in which lens driving devices are arranged side by side, there is a high possibility that magnetic interference will occur between the lens driving devices.

[0007] On the other hand, Patent Document 2 discloses a lens driving device that applies ultrasonic motors to an AF driving unit and an OIS driving unit. The lens driving device disclosed in Patent Document 2 is magnetless and can reduce the influence of external magnetism, but has a complex structure and is difficult to reduce in size and height.

[0008] An object of the present invention is to provide a rotary drive device that can reduce the influence of external magnetism and can be made smaller and thinner. [Means for solving the problem]

[0009] One aspect of the rotation drive device according to the present invention is to The device has an outer periphery having a shape surrounding a circular opening and on which wiring is arranged, and a recess that opens upward and is recessed downward is provided in an arc shape along the circumferential direction on the outer periphery. A fixed portion; The fixing portion The outer periphery of A ring-shaped rotating body placed on top a rotating body having an annular portion extending along the circumferential direction and a protruding portion protruding downward from the annular portion at a position corresponding to the recessed portion, and, At a position where the recess and the protrusion are provided, a sliding support part that supports sliding of the rotating body relative to the fixed part; an ultrasonic motor fixed to the fixed portion on the outer circumferential side of the rotor, the ultrasonic motor having a piezoelectric element and a resonator, both of which are plate-shaped and have their plate surfaces bonded together; a power transmission section that is fixed to the rotor on an outer circumferential side of the rotor and is connected to the resonance section, the power transmission section having a length in a circumferential direction of the rotor, The resonating unit resonates with the vibration of the piezoelectric element that receives power through the wiring to generate linear motion, and the power transmission unit By linear motion Moving in the circumferential direction , the rotating body is caused to rotate. Effect of the Invention

[0010] According to the present invention, it is possible to provide a rotary drive device that can reduce the influence of external magnetism and can be made smaller and thinner. [Brief description of the drawings]

[0011] [Figure 1] 1A and 1B are diagrams showing a smartphone equipped with a camera module according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the appearance of the camera module. [Diagram 3] 3A and 3B are external perspective views of the lens driving device. [Figure 4] FIG. 4 is an exploded perspective view of the lens driving device. [Diagram 5] FIG. 5 is an exploded perspective view of the lens driving device. [Figure 6] 6A and 6B are perspective views of the first OIS driver. [Figure 7] FIG. 7 is an exploded perspective view of the OIS movable portion. [Figure 8] FIG. 8 is an exploded perspective view of the OIS movable portion. [Figure 9] FIG. 9 is a perspective view of the AF drive unit. [Figure 10] 10A and 10B are diagrams showing the behavior of the lens holder accompanying the rotation of the rotation spacer. [Figure 11] 11A and 11B are diagrams showing an automobile as a camera-mounted device equipped with an on-board camera module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0013] 1A and 1B are diagrams showing a smartphone M (an example of a camera-mounted device) equipped with a camera module A according to an embodiment of the present invention, in which Fig. 1A is a front view of the smartphone M and Fig. 1B is a rear view of the smartphone M.

[0014] The smartphone M has a dual camera consisting of two rear cameras OC1 and OC2. In this embodiment, the camera module A is applied to the rear cameras OC1 and OC2. The camera module A is equipped with an AF function and an OIS function, and can automatically adjust the focus when photographing a subject, and can optically correct shake (vibration) that occurs during shooting to capture images without blur.

[0015] FIG. 2 is an external perspective view of the camera module A. FIG. 3A and FIG. 3B are external perspective views of the lens driving device 1. FIG. 3B shows a state in which FIG. 3A is rotated 180° around the Z axis. As shown in FIG. 2, FIG. 3A, and FIG. 3B, in this embodiment, an orthogonal coordinate system (X, Y, Z) is used for explanation. The same orthogonal coordinate system (X, Y, Z) is used in the drawings described later.

[0016] For example, when actually photographing with a smartphone M, the camera module A is mounted so that the X direction is the up-down direction (or left-right direction), the Y direction is the left-right direction (or up-down direction), and the Z direction is the front-back direction. That is, the Z direction is the optical axis direction, the upper side (+Z side) in the figure is the light receiving side (subject side) in the optical axis direction, and the lower side (-Z side) is the image forming side in the optical axis direction. In addition, the X and Y directions are "optical axis orthogonal directions" perpendicular to the Z axis, and the XY plane is the "optical axis orthogonal plane" perpendicular to the optical axis.

[0017] As shown in FIG. 2 etc., the camera module A includes a lens driving device 1 that realizes AF and OIS functions, a lens unit 2 having a lens housed in a cylindrical lens barrel, an imaging unit (not shown) that captures the subject image formed by the lens unit 2, and a cover 3 that covers the entire module.

[0018] The cover 3 is a covered square cylinder having a rectangular shape in a plan view from the optical axis direction. In this embodiment, the cover 3 has a square shape in a plan view. The cover 3 has a roughly circular opening 3a on the upper surface. The lens unit 2 faces the outside through the opening 3a, and is configured to protrude beyond the opening surface of the cover 3 to the light receiving side as the lens unit 2 moves in the optical axis direction. The cover 3 is fixed to the OIS fixing unit 20 (see FIG. 4) of the lens driving device 1 by, for example, adhesive.

[0019] The imaging unit (not shown) is disposed on the imaging side in the optical axis direction of the lens driving device 1. The imaging unit (not shown) has, for example, an image sensor board and an imaging element mounted on the image sensor board. The imaging element is, for example, configured with a CCD (charge-coupled device) type image sensor, a CMOS (complementary metal oxide semiconductor) type image sensor, or the like. The imaging element captures an image of a subject formed by the lens unit 2. The lens driving device 1 is mounted on the image sensor board (not shown) and is mechanically and electrically connected thereto. A control unit that controls the driving of the lens driving device 1 may be provided on the image sensor board, or may be provided in a camera-equipped device (smartphone M in this embodiment) on which the camera module A is mounted.

[0020] 4 and 5 are exploded perspective views of the lens driving device 1. Fig. 5 shows a state in which Fig. 4 is rotated 90 degrees around the Z axis and viewed from below. As shown in Figures 4 and 5, in this embodiment, the lens driving device 1 includes an OIS movable part 10 (second movable part), an OIS fixed part 20 (second fixed part), an OIS driving part 30 (XY direction driving part), and an OIS support part 40 (second support part).

[0021] The OIS movable part 10 is a part that swings in a plane perpendicular to the optical axis during shake correction. The OIS movable part 10 includes an AF unit having an AF movable part 11 (first movable part), a first stage 12 (first fixed part), an AF drive part 13 (Z direction drive part), an AF support part 14 (first support part), and a rotation spacer 15 (see FIG. 7, etc.). The OIS fixed portion 20 is a portion to which the OIS movable portion 10 is connected via the OIS support portion 40. The OIS fixed portion 20 includes a base 21. The OIS support portion 40 supports the OIS movable portion 10 in a state spaced apart in the optical axis direction from the OIS fixed portion 20. The OIS support portion 40 includes second stages 41X, 41Y, balls 42, 43, and an OIS biasing member 44. The OIS movable part 10 is disposed at a distance from the OIS fixed part 20 in the optical axis direction, and is connected to the OIS fixed part 20 via an OIS support part 40. In addition, the OIS movable part 10 and the OIS fixed part 20 are biased in directions approaching each other by OIS biasing members 44 disposed at four points on the outer circumferential surface of the OIS movable part 10. In this embodiment, the OIS movable part 10 can be swung with high precision within the XY plane by restricting the rolling directions of the balls 42, 43 (a total of 11 balls) constituting the OIS support part 40. The number of balls 42, 43 constituting the OIS support part 40 can be changed as appropriate.

[0022] The base 21 is a rectangular member in a plan view formed from a molding material such as polyarylate (PAR), a PAR alloy (e.g., PAR / PC) made by mixing multiple resin materials including PAR, or liquid crystal polymer (LCP), and has a circular opening 21a in the center. The base 21 has, at two corners, OIS motor fixing portions 21b on which the OIS driving unit 30 is disposed. The OIS motor fixing portion 21b is formed to protrude from the main surface of the base 21 toward the light receiving side in the optical axis direction, and has a shape capable of holding the OIS driving unit 30.

[0023] Although not shown, terminal fittings and wiring are arranged, for example, by insert molding, on the base 21. Also arranged on the base 21 is a sensor board on which the Hall elements 51X and 51Y are mounted. The wiring includes a power supply line to the AF driving unit 13 (see FIG. 7 etc.) and the OIS driving unit 30. The wiring is exposed, for example, from the peripheral edge of the base 21 and is electrically connected to the wiring formed on the sensor substrate and the OIS biasing member 44.

[0024] The base 21 also has ball accommodating sections 21c, 21d, and 21e that accommodate the ball 42. The ball accommodating section 21c is formed to be recessed in a circular shape, and accommodates the ball 42 interposed between the base 21 and the first stage 12. The ball accommodating section 21d is formed to be recessed in a rectangular shape extending in the X direction, and accommodates the ball 42 interposed between the base 21 and the second stage 41X. The ball accommodating section 21e is formed to be recessed in a rectangular shape extending in the Y direction, and accommodates the ball 42 interposed between the base 21 and the second stage 41Y. The side surfaces of the ball accommodating sections 21d and 21e are formed, for example, in a tapered shape such that the groove width narrows toward the bottom surface side.

[0025] The sensor substrate (not shown) has wiring (not shown) including power supply lines and signal lines for the Hall elements 51X, 51Y. The Hall elements 51X, 51Y are electrically connected to wiring (not shown) of the base 21 via wiring (not shown) formed on the sensor substrate. Magnets 52X, 52Y are disposed on the second stages 41X, 41Y at positions facing the Hall elements 51X, 51Y. The positions of the OIS movable part 10 in the X and Y directions are detected by an XY position detection unit consisting of the Hall elements 51X, 51Y and the magnets 52X, 52Y.

[0026] The second stages 41X and 41Y are formed of, for example, a liquid crystal polymer and have an overall L-shape. The inner peripheral surfaces of the second stages 41X and 41Y are formed in an arc shape along the outer shape of the lens holder 11. The second stages 41X and 41Y are arranged along the X direction and the Y direction, respectively. In addition, adjacent portions of the second stages 41X and 41Y are spaced apart at a predetermined interval so that the second stages 41X and 41Y can move independently of each other. The outer surfaces of the second stages 41X, 41Y are recessed inward, and the OIS driving parts 30X, 30Y are positioned therein when the lens driving device 1 is assembled. In this embodiment, the second stages 41X, 41Y are formed in an L-shape as a whole, and the second stages 41X, 41Y are disposed below a portion of the first stage 12 that is formed to be thin, thereby reducing the height of the OIS movable part 10.

[0027] The second stages 41X and 41Y are provided with engagement pieces 41e and 41f protruding toward the light receiving side in the optical axis direction on their peripheries. One end of the OIS power transmission unit 33 is fixed to the engagement pieces 41e and 41f. The engagement pieces 41e and 41f are loosely fitted into engagement grooves 12g and 12h provided in the first stage 12. Specifically, the engagement piece 41e and the engagement groove 12g are engaged with each other to such an extent that the surfaces facing each other in the Y direction do not come into contact with each other when the first stage 12 moves in the Y direction, and the engagement piece 41f and the engagement groove 12h are engaged with each other to such an extent that the surfaces facing each other in the Y direction do not come into contact with each other when the first stage 12 moves in the Y direction. That is, the second stage 41X is not displaced even when the first stage 12 moves in the Y direction, and the second stage 41Y is not displaced even when the first stage 12 moves in the X direction.

[0028] Each of the second stages 41X, 41Y has three ball receiving portions 41a, 41b for receiving balls 42 on its lower surface (the surface on the image formation side in the optical axis direction). The ball receiving portion 41a faces the ball receiving portions 21d, 21e of the base 21. The ball receiving portions 41a, 41b are formed to be recessed in an oval shape extending in the X direction and the Y direction, respectively. In addition, the side surfaces of the ball receiving portions 41a, 41b are formed in a tapered shape so that the groove width narrows toward the bottom surface side. Each of the second stages 41X and 41Y has two ball receiving portions 41c and 41d on its upper surface (the surface on the light receiving side in the optical axis direction) for receiving the ball 43. The ball receiving portions 41c and 41d are recessed in an oval shape extending in the Y direction and the X direction, respectively. The side surfaces of the ball receiving portions 41c and 41d are tapered so that the groove width narrows toward the bottom surface side.

[0029] The ball 42 is sandwiched between the ball receiving portions 21c to 21e of the base 21, the ball receiving portion 12b of the first stage 12, and the ball receiving portions 41a, 41b of the second stages 41X, 41Y. In particular, the ball 42 is in multi-point contact between the ball receiving portions 21d, 21e of the base 21 and the ball receiving portions 41a, 41b of the second stages 41X, 41Y. Therefore, the ball 42 rolls stably in the X direction or Y direction. Moreover, the ball 43 is sandwiched in multi-point contact between the ball receiving portions 41c, 41d of the second stages 41X, 41Y and the lower surface of the first stage 12. Therefore, the ball 43 rolls stably in the X direction or Y direction.

[0030] The OIS biasing member 44 is, for example, a tension coil spring, and connects the OIS movable part 10 and the OIS fixed part 20. In this embodiment, one end of the OIS biasing member 44 is connected to the wiring (not shown) of the base 21, and the other end is connected to the wiring (not shown) of the first stage 12. The OIS biasing member 44 receives a tensile load when the OIS movable part 10 and the OIS fixed part 20 are connected, and acts to move the OIS movable part 10 and the OIS fixed part 20 closer to each other. That is, the OIS movable part 10 is held by the OIS biasing member 44 in a state in which it is biased in the optical axis direction (a state in which it is pressed against the base 21) so as to be swingable within the XY plane. This allows the OIS movable part 10 to be held in a stable state without rattling. In this embodiment, the OIS biasing member 44 functions as a power supply line to the AF drive unit 13.

[0031] The OIS driving unit 30 is an actuator that moves the OIS movable part 10 in the X direction and the Y direction. Specifically, the OIS driving unit 30 is composed of a first OIS driving unit 30X (first XY direction driving unit) that moves the OIS movable part 10 in the X direction, and a second OIS driving unit 30Y (second XY direction driving unit) that moves the OIS movable part 10 in the Y direction. The first OIS driving unit 30X is fixed to the OIS motor fixing portion 21b of the base 21 so as to extend along the X direction. The second OIS driving unit 30Y is fixed to the OIS motor fixing portion 21b of the base 21 so as to extend along the Y direction. That is, the first OIS driving unit 30X and the second OIS driving unit 30Y are disposed along sides that are perpendicular to each other.

[0032] The configuration of OIS driving unit 30 is shown in Figures 6A and 6B. Figure 6A shows the assembled state of each component of OIS driving unit 30, and Figure 6B shows the disassembled state of each component of OIS driving unit 30. Note that although Figures 6A and 6B show second OIS driving unit 30Y, the main configuration of first OIS driving unit 30X is similar, so they are treated as figures showing OIS driving unit 30.

[0033] 6A and 6B, the OIS driving unit 30 has an OIS resonating unit 31, an OIS piezoelectric element 32, an OIS electrode (not shown), and an OIS power transmission unit 33. The OIS resonating unit 31, the OIS piezoelectric element 32, and the OIS electrode (not shown) configure an ultrasonic motor, and the driving force of the ultrasonic motor is transmitted to the second stages 41X and 41Y via the OIS power transmission unit 33.

[0034] The OIS piezoelectric element 32 is, for example, a plate-shaped element made of a ceramic material, and generates vibrations when a high-frequency voltage is applied. The OIS electrodes (not shown) sandwich the OIS resonating portion 31 and the OIS piezoelectric element 32, and apply a voltage to the OIS piezoelectric element 32. The OIS electrodes are electrically connected to wiring (not shown) of the base 21, for example.

[0035] The OIS resonating unit 31 is made of a conductive material, and resonates with the vibration of the OIS piezoelectric element 32 to convert the vibration motion into linear motion. In this embodiment, the OIS resonating unit 31 has a substantially rectangular body 31a sandwiched between the OIS piezoelectric element 32, two arms 31b extending from the upper and lower parts of the body 31a, a protruding portion 31c protruding from the center of the body 31a, and a conductive portion 31d extending from the center of the body 31a to the opposite side to the protruding portion 31c. The conductive portion 31d is electrically connected to, for example, the wiring of the base 21. The two arms 31b have symmetrical shapes, and their free ends abut against the OIS power transmission unit 33, and resonate with the vibration of the OIS piezoelectric element 32 to deform symmetrically.

[0036] The OIS piezoelectric element 32 is attached to the body 31a of the OIS resonating unit 31 in the thickness direction and is sandwiched between OIS electrodes (not shown), thereby electrically connecting them to each other. For example, one end of a power supply path is connected to the OIS electrode and the other end is connected to the current-carrying portion 31d of the OIS resonating unit 31, so that a voltage is applied to the OIS piezoelectric element 32 and vibration is generated.

[0037] The OIS resonating unit 31 has at least two resonant frequencies and deforms in a different manner for each resonant frequency. In other words, the overall shape of the OIS resonating unit 31 is set so that it deforms in a different manner for the two resonant frequencies. The different behaviors are a behavior that moves the OIS power transmission unit 33 forward in the X direction or Y direction and a behavior that moves it backward.

[0038] The OIS power transmission unit 33 is a chucking guide extending in one direction, one end of which is connected to the OIS resonating unit 31, and the other end of which is connected to the second stages 41X and 41Y. The OIS power transmission unit 33 has an OIS motor contact portion 33a, a stage fixing portion 33c, and a connecting portion 33b. The OIS motor contact portion 33a is formed, for example, in a substantially L-shaped cross section, and abuts against a free end of the arm portion 31b of the OIS resonating unit 31. The stage fixing portion 33c is disposed at an end of the OIS power transmission unit 33, and is fixed to the engagement pieces 41e and 41f (see FIG. 4, etc.) of the second stages 41X and 41Y. The connecting portion 33b is a portion that connects the OIS motor contact portion 33a and the stage fixing portion 33c, and is formed in parallel to each other by branching into two from the stage fixing portion 33c.

[0039] The width between the OIS motor contact portions 33a is set to be wider than the width between the free ends of the arm portions 31b of the OIS resonating portion 31. As a result, when the OIS power transmission portion 33 is attached to the OIS resonating portion 31, the OIS power transmission portion 33 functions as a leaf spring, and a biasing force acts in a direction that pushes apart the arm portions 31b of the OIS resonating portion 31. This biasing force holds the OIS power transmission portion 33 between the free ends of the arm portions 31b of the OIS resonating portion 31, and the driving force from the OIS resonating portion 31 is efficiently transmitted to the OIS power transmission portion 33.

[0040] Since the OIS resonating unit 31 and the OIS power transmission unit 33 are only in contact with each other in a biased state, the movement distance (stroke) of the OIS movable unit 10 can be increased by simply enlarging the contact portion in the X or Y direction without increasing the external dimensions of the lens driving device 1.

[0041] The first OIS drive section 30X is fixed so as to connect the base 21 and the second stage 41X, and the second OIS drive section 30X is fixed so as to connect the base 21 and the second stage 41Y. During shake correction in the X direction by the first OIS driving unit 30X, the second stage 41X and the first stage 12 move, and the second stage 41Y does not move. On the other hand, during shake correction in the Y direction by the second OIS driving unit 30Y, the second stage 41Y and the first stage 12 move, and the second stage 41X does not move. That is, the movement of the OIS movable part 10 by one OIS driving unit 30 is not hindered by the structure of the other OIS driving unit 30. Since the rotation of the OIS movable part 10 around the Z axis can be prevented, the OIS movable part 10 can be swung accurately within the XY plane.

[0042] 7 and 8 are exploded perspective views of the OIS movable part 10. Fig. 8 shows a view rotated 90° around the Z axis from Fig. 7 as seen from below. Note that Fig. 8 shows a state in which the AF drive part 13 is attached to a rotation spacer 15. As shown in FIGS. 7 and 8, in this embodiment, the OIS movable section 10 has an AF movable section 11, a first stage 12, an AF drive section 13, an AF support section 14, a rotation spacer 15, and the like.

[0043] The AF movable part 11 is a part that moves in the optical axis direction during focusing. The AF movable part 11 is disposed radially apart from the first stage 12 (first fixed part) and is connected to the first stage 12 via the AF support part 14.

[0044] The AF movable part 11 is composed of a lens holder (hereinafter referred to as "lens holder 11") that holds the lens part 2 (see FIG. 2). The lens holder 11 is formed of, for example, polyarylate (PAR), a PAR alloy in which multiple resin materials including PAR are mixed, a liquid crystal polymer, or the like. The lens holder 11 has a cylindrical lens housing part 11a. The lens part 2 (see FIG. 2) is fixed to the lens housing part 11a by, for example, adhesion.

[0045] The lens holder 11 has a sliding portion 11b that protrudes radially outward from the upper outer periphery of the lens housing portion 11a. The lower surface 11c of the sliding portion 11b is formed to be inclined in the optical axis direction, and the sliding portion 11b rises toward the image formation side in the optical axis direction in conjunction with the rotation of the rotating spacer 15, so that the lens holder 11 moves in the optical axis direction.

[0046] The first stage 12 is a portion that supports the lens holder 11 via the AF support portion 14. Below the first stage 12, second stages 41X and 41Y are disposed via balls 43. During shake correction, the first stage 12 moves in the X direction and Y direction in conjunction with the movement of the second stages 41X and 41Y.

[0047] The first stage 12 is a substantially rectangular cylindrical member and is made of, for example, a liquid crystal polymer. The first stage 12 has a substantially circular opening 12a in a portion corresponding to the lens holder 11. In the first stage 12, the portions corresponding to the second stages 41X, 41Y are formed to be thinner than other portions by the thickness of the second stages 41X, 41Y.

[0048] The first stage 12 has a ball receiving section 12b on its underside, which receives the ball 42 interposed between it and the base 21. The ball receiving section 12b is formed in a circular recess at a position facing the ball receiving section 21e of the base 21 in the Z direction. The first stage 12 also has ball receiving sections 12m and 12n on its underside, which receive the ball 43 interposed between it and the second stage 41X and 41Y. The ball receiving sections 12m and 12n are formed in an oval recess extending in the Y and X directions at positions facing the ball receiving sections 41c and 41d of the second stage 41X and 41Y in the Z direction. The side surfaces of the ball receiving sections 12m and 12n are formed in a tapered shape so that the groove width narrows toward the bottom surface side. The first stage 12 has upper spring fixing portions 12c at the four corners of the upper surface to fix the AF support portion 14. The upper spring fixing portions 12c are formed to protrude further toward the light receiving side in the optical axis direction than the main surface 12j.

[0049] The first stage 12 has a spacer arrangement portion 12d and a motor fixing portion 12f on the periphery of the opening 12a. The spacer arrangement portion 12d is recessed toward the imaging side in the optical axis direction from the main surface 12j, and has a ball housing portion 12e that houses a ball 17. The step between the spacer arrangement portion 12d and the main surface 12j restricts the rotation of the rotating spacer 15. The AF drive unit 13 is fixed to the motor fixing portion 12f.

[0050] In this embodiment, three spacer arrangement parts 12d are provided at equal intervals along the circumferential direction. This stabilizes the attitude of the rotation spacer 15, so that the rotation operation can be controlled with high precision. Note that two or four or more spacer arrangement parts 12d may be provided.

[0051] Although not shown in the figure, wiring is arranged on the first stage 12, for example, by insert molding. The wiring is appropriately exposed from the first stage 12, and this portion is electrically connected to the AF drive unit 13 and the OIS biasing member 44. Power is supplied to the AF drive unit 13 via the OIS biasing member 44 and the wiring of the first stage 12.

[0052] Furthermore, engagement grooves 12g, 12h are provided on one side surface along the X direction and one side surface along the Y direction of the first stage 12 at positions corresponding to the engagement pieces 41e, 41f of the second stages 41X, 41Y. When the lens driving device 1 is in an assembled state, the engagement pieces 41e, 41f of the second stages 41X, 41Y engage with the engagement grooves 12g, 12h of the first stage 12. As a result, the OIS movable part 10 (first stage 12) moves in the X direction or Y direction in conjunction with the movement of the second stages 41X, 41Y.

[0053] The AF support part 14 supports the lens holder 11 movably in the optical axis direction with respect to the first stage 12. In the present embodiment, the AF support part 14 is configured with an upper spring (hereinafter referred to as "upper spring 14") that elastically supports the lens holder 11 on the light receiving side (upper side) in the optical axis direction with respect to the first stage 12. The upper spring 14 is a leaf spring made of a metal material such as beryllium copper, nickel copper, stainless steel, or the like.

[0054] The upper spring 14 has a lens holder fixing portion 14a, a stage fixing portion 14b, and an arm portion 14c. The lens holder fixing portion 14a has a shape corresponding to the upper surface of the lens housing portion 11a of the lens holder 11. The stage fixing portion 14b is provided at a position corresponding to the upper spring fixing portion 12c of the first stage 12. The arm portion 14c extends from the lens holder fixing portion 14a and connects the lens holder fixing portion 14a and the stage fixing portion 14b.

[0055] The upper spring 14 is positioned and fixed to the lens holder 11, for example, by engaging a positioning piece 14d provided on the lens holder fixing portion 14a with a positioning hole 11d provided in the slide portion 11b of the lens holder 11. The upper spring 14 is also fixed to the first stage 12, for example, by bonding the stage fixing portion 14b to an upper spring fixing portion 12c of the first stage 12. When the lens holder 11 moves in the optical axis direction, the lens holder fixing portion 14a is displaced together with the lens holder 11, and the arm portion 14c is elastically deformed.

[0056] The rotating spacer 15 is a rotating body that rotates about the optical axis in response to the linear motion of the AF driving unit 13. The rotating spacer 15 has an annular shape and is disposed along the outer circumferential surface of the lens holder 11. The rotating spacer 15 also has a motor connection portion 15d to which the AF driving unit 13 is connected.

[0057] The rotating spacer 15 has an annular portion 15a and a stage fixing portion 15b. The stage fixing portion 15b is provided at a position corresponding to the spacer arrangement portion 12d of the first stage 12, and is formed, for example, protruding from the annular portion 15a toward the imaging side in the optical axis direction. An upper surface 15c of the stage fixing portion 15b is formed to be inclined toward the optical axis direction, and the slide portion 11b of the lens holder 11 is placed thereon (hereinafter referred to as "holder guide portion 15c").

[0058] The holder guide portion 15c of the rotating spacer 15 and the slide portion 11b of the lens holder 11 constitute an end face cam 18 (see FIG. 10A, etc.) in which the slide portion 11b slides along the holder guide portion 15c as the rotating spacer 15 rotates. The end face cam 18 is a mechanical element that converts rotational motion into linear motion in the optical axis direction.

[0059] In this embodiment, three end cams 18 are provided at equal intervals along the circumferential direction. As a result, the rotational motion of the rotating spacer 15 is converted into linear motion by the end cams 18 and is evenly transmitted to the lens holder 11, making it possible to precisely control the movement of the lens holder 11. Note that two, four or more end cams 18 may be provided at equal intervals along the circumferential direction.

[0060] In this embodiment, a ball 16 is disposed between the holder guide portion 15c and the sliding portion 11b, and the two are indirectly in contact with each other, allowing smooth sliding between the rotating spacer 15 and the lens holder 11. It is also possible to have the rotating spacer 15 and the lens holder 11 directly in contact with each other and slide between them, without disposing the ball 16 between them. In addition, balls 17 are disposed between the rotating spacer 15 and the first stage 12 so that the rotating spacer 15 rotates smoothly on the first stage 12.

[0061] The AF driving unit 13 is an actuator that moves the lens holder 11 in the Z direction. The AF driving unit 13 is composed of an ultrasonic motor, similar to the OIS driving unit 30. The AF driving unit 13 is fixed to a motor fixing portion 12f of the first stage 12 so as to fit along the peripheral surface of the rotating spacer 15.

[0062] The configuration of the AF drive unit 13 is shown in FIG. 9, the AF driving unit 13 has an AF resonating unit 131, an AF piezoelectric element 132, an AF electrode (not shown), and an AF power transmission unit 133. The AF resonating unit 131, the AF piezoelectric element 132, and the AF electrode (not shown) configure an ultrasonic motor, and the driving force of the ultrasonic motor is transmitted to the rotating spacer 15 via the AF power transmission unit 133.

[0063] The AF piezoelectric element 132 is, for example, a plate-shaped element made of a ceramic material, and generates vibrations when a high-frequency voltage is applied. The AF electrodes (not shown) sandwich the AF resonating portion 131 and the AF piezoelectric element 132, and apply a voltage to the AF piezoelectric element 132. The AF electrodes are electrically connected to wiring (not shown) of the first stage 12, for example.

[0064] The AF resonating unit 131 is made of a conductive material, and resonates with the vibration of the AF piezoelectric element 132 to convert the vibration motion into linear motion. In this embodiment, the AF resonating unit 131 has a substantially rectangular body 131a sandwiched between the AF piezoelectric element 132, two arms 131b extending from the upper and lower parts of the body 131a, a protruding part 131c protruding from the center of the body 131a, and a current-carrying part 131d extending from the center of the body 131a to the opposite side to the protruding part 131c and electrically connected to a power supply path (the wiring of the first stage 12). The two arms 131b have symmetrical shapes, and their free ends abut against the AF power transmission part 133, and resonate with the vibration of the AF piezoelectric element 132 to deform symmetrically.

[0065] The AF piezoelectric element 132 is attached to the body 131a of the AF resonating unit 131 in the thickness direction and is sandwiched between AF electrodes (not shown) so that they are electrically connected to each other. For example, when the current-carrying portion 131d and the AF electrodes of the AF resonating unit 131 are connected to wiring (not shown) of the first stage 12, a voltage is applied to the AF piezoelectric element 132, causing vibration.

[0066] The AF resonating unit 131 has at least two resonant frequencies, similar to the OIS resonating unit 31, and deforms in a different manner for each resonant frequency. In other words, the overall shape of the AF resonating unit 131 is set so that it deforms in a different manner for the two resonant frequencies. The different behaviors are a behavior that moves the AF power transmission unit 133 forward and a behavior that moves it backward in the circumferential direction.

[0067] The AF power transmission unit 133 is a chucking guide extending in the circumferential direction, one end of which is connected to the AF resonating unit 131 and the other end of which is connected to the rotating spacer 15. The AF power transmission unit 133 has an AF motor abutment unit 133a, a spacer fixing unit 133c, and a connecting unit 133b. The AF motor abutment unit 133a is formed, for example, in a flat plate shape and abuts against a free end of the arm unit 131b of the AF resonating unit 131. The spacer fixing unit 133c is disposed at an end of the AF power transmission unit 133 and fixed to the motor connection unit 15d of the rotating spacer 15. The connecting unit 133b is a portion that connects the AF motor abutment unit 133a and the spacer fixing unit 133c, and is formed by branching into two from the spacer fixing unit 133c and curving in parallel to each other along the housing direction.

[0068] The AF power transmission unit 133 moves in response to the linear motion of the AF resonating unit 131, but one end of the AF power transmission unit 133 is connected to and constrained by the rotation spacer 15, so that the arm unit 131b of the AF resonating unit 131 and the AF motor abutment unit 133a of the AF power transmission unit 133 slide against each other, causing the AF power transmission unit 133 to rotate. In other words, it can be said that the AF drive unit 13, including the AF power transmission unit 133, converts vibration motion into rotational motion.

[0069] The width between the AF motor abutment portions 133a is set to be wider than the width between the free ends of the arm portions 131b of the AF resonating portion 131. As a result, when the AF power transmission portion 133 is attached to the AF resonating portion 131, the AF power transmission portion 133 functions as a leaf spring, and a biasing force acts in a direction that pushes apart the arm portions 131b of the AF resonating portion 131. This biasing force holds the AF power transmission portion 133 between the free ends of the arm portions 131b of the AF resonating portion 131, and the driving force from the AF resonating portion 131 is efficiently transmitted to the AF power transmission portion 133.

[0070] Since the AF resonator unit 131 and the AF power transmission unit 133 are only in contact with each other in a biased state, the amount of rotation of the rotating spacer 15, i.e., the movement distance of the lens holder 11 (stroke in the optical axis direction) can be increased by simply enlarging the contact portion in the circumferential direction, without increasing the external size of the lens driving device 1.

[0071] In the lens driving device 1, when a voltage is applied to the AF driving unit 13, the AF piezoelectric element 132 vibrates, and the AF resonating unit 131 deforms in a manner according to the frequency. The driving force of the AF driving unit 13 rotates the rotating spacer 15, and the lens holder 11 moves in the optical axis direction, thereby performing focusing.

[0072] 10A and 10B show specific examples of the behavior of the lens holder 11 accompanying the rotation of the rotation spacer 15. Fig. 10A shows the initial state in which the AF driving unit 13 is not driven, and Fig. 10B shows the state in which the AF driving unit 13 is driven. 10A and 10B, when the AF drive unit 13 is driven and the AF power transmission unit 133 is drawn toward the AF resonator 131, the rotating spacer 15 connected to the AF power transmission unit 133 rotates. In response to this, the end face cam 18 operates, and the slide portion 11b of the lens holder 11 moves up along the holder guide portion 15c of the rotating spacer 15, and the lens holder 11 moves toward the light receiving side in the optical axis direction.

[0073] In the lens driving device 1, when a voltage is applied to the OIS driving unit 30, the OIS piezoelectric element 32 vibrates, and the OIS resonating unit 31 deforms in a manner according to the frequency. The OIS power transmission unit 33 slides in the X direction or Y direction due to the driving force of the OIS driving unit 30. Accordingly, the OIS movable unit 10 moves in the X direction or Y direction, and shake correction is performed.

[0074] Specifically, when the first OIS driving unit 30X is driven and the OIS power transmission unit 33 moves in the X direction, power is transmitted from the base 21 on which the first OIS driving unit 30X is disposed to the second stage 41X. Since the ball 42 (the ball 42 disposed in the ball receiving portion 21d) sandwiched between the second stage 41X and the base 21 is disposed so as to be able to roll in the X direction, the second stage 41X moves in the X direction relative to the base 21. Since the ball 43 (the ball 43 disposed in the ball receiving portion 41c) sandwiched between the first stage 12 and the second stage 41X cannot roll in the X direction, the position of the first stage 12 in the X direction relative to the second stage 41X is maintained, and the first stage 12 moves in the X direction in conjunction with the second stage 41X. At this time, the ball 43 (ball 43 arranged in ball receiving portion 41d) held between the second stage 41Y and the first stage 12 is arranged to be able to roll in the X direction, so the first stage 12 slides smoothly on the second stage 41Y. In addition, the movement of the second stage 41Y in the X direction relative to the base 21 is restricted by the ball 42 (ball 42 arranged in ball receiving portion 21e) held between the second stage 41Y and the base 21. Therefore, the second stage 41Y does not displace relative to the base 21, and only the second stage 41X and the first stage 12 move in the X direction.

[0075] Similarly, when the second OIS driving unit 30Y is driven and the OIS power transmission unit 33 moves in the Y direction, power is transmitted from the base 21 on which the second OIS driving unit 30Y is disposed to the second stage 41Y. Since the ball 42 (the ball 42 disposed in the ball receiving portion 21e) sandwiched between the second stage 41Y and the base 21 is disposed so as to be able to roll in the Y direction, the second stage 41Y moves in the Y direction relative to the base 21. Since the ball 43 (the ball 43 disposed in the ball receiving portion 41d) sandwiched between the first stage 12 and the second stage 41Y cannot roll in the Y direction, the position of the first stage 12 in the Y direction relative to the second stage 41Y is maintained, and the first stage 12 moves in the Y direction in conjunction with the second stage 41Y. At this time, the ball 43 (ball 43 arranged in the ball receiving portion 41c) sandwiched between the second stage 41X and the first stage 12 is arranged so as to be able to roll in the Y direction, so that the first stage 12 slides smoothly on the second stage 41X. In addition, the movement of the second stage 41X in the Y direction relative to the base 21 is restricted by the ball 42 (ball 42 arranged in the ball receiving portion 21d) sandwiched between the second stage 41X and the base 21. Therefore, the second stage 41X does not displace relative to the base 21, and only the second stage 41Y and the first stage 12 move in the Y direction.

[0076] In this way, the second stages 41X and 41Y do not interfere with each other and can move independently. That is, the first OIS driver 30X connected to the second stage 41X does not receive a force in the Y direction due to the movement of the second stage 41Y, and the second OIS driver 30Y connected to the second stage 41Y does not receive a force in the X direction due to the movement of the second stage 41X. Therefore, it is possible to perform shake correction in the XY plane with high accuracy.

[0077] In this way, the OIS movable part 10 swings in the XY plane, and shake correction is performed. Specifically, the voltage applied to the OIS drive part 30 is controlled based on a detection signal indicating angular shake from a shake detection part (e.g., a gyro sensor, not shown) so that the angular shake of the camera module A is offset. At this time, the translational movement of the OIS movable part 10 can be accurately controlled by feeding back the detection result of an XY position detection part composed of magnets 52X, 52Y and Hall elements 51X, 51Y.

[0078] Thus, the lens driving device 1 according to the embodiment includes a first stage 12 (first fixed part), a lens holder 11 (first movable part) that holds the lens part 2 and is disposed apart from the first stage 12, an AF support part 14 (first support part) that supports the lens holder 11 relative to the first stage 12, and an AF drive part 13 (Z-direction drive part) that is composed of an ultrasonic motor that converts vibration motion into linear motion and moves the lens holder 11 in the optical axis direction (Z direction) relative to the first stage 12. The lens driving device 1 includes a rotating spacer 15 (rotating body) that rotates about the optical axis upon receiving the linear motion of the AF drive part 13, and an end face cam 18 (mechanical element) that converts the rotational motion of the rotating spacer 15 into linear motion in the optical axis direction, and the lens holder 11 moves in the optical axis direction as the rotating spacer 15 rotates.

[0079] According to the lens driving device 1, the AF driving unit 13 is composed of an ultrasonic motor, so that it is possible to reduce the influence of external magnetism and to achieve a smaller size and lower height. Therefore, even if the camera module A having the lens driving device 1 is arranged close to each other, as in the case of a smartphone M, there is no magnetic influence, so that it is extremely suitable for a dual camera.

[0080] The invention made by the inventor has been specifically described above based on an embodiment, but the present invention is not limited to the above embodiment and can be modified within the scope of the gist of the invention.

[0081] For example, in the embodiment, a smartphone M, which is a mobile terminal with a camera, has been described as an example of a camera-mounted device equipped with a camera module A, but the present invention can be applied to a camera-mounted device having a camera module and an image processing unit that processes image information obtained by the camera module. Camera-mounted devices include information devices and transport equipment. Information devices include, for example, mobile phones with cameras, notebook computers, tablet terminals, portable game consoles, web cameras, and in-vehicle devices with cameras (for example, rear monitor devices and drive recorder devices). Transport equipment includes, for example, automobiles.

[0082] 11A and 11B are diagrams showing an automobile V as a camera-mounted device equipped with an in-vehicle camera module VC (Vehicle Camera). FIG. 11A is a front view of the automobile V, and FIG. 11B is a rear perspective view of the automobile V. The automobile V is equipped with the camera module A described in the embodiment as the in-vehicle camera module VC. As shown in FIGS. 11A and 11B, the in-vehicle camera module VC is attached, for example, to the windshield facing forward or to the rear gate facing backward. This in-vehicle camera module VC is used for a backup monitor, a drive recorder, a collision avoidance control, an automatic driving control, etc.

[0083] In addition, in the embodiment, an end face cam 18 composed of the slide portion 11b of the lens holder 11 and the holder guide portion 15c of the rotating spacer 15 is utilized, but other cam structures, etc. may be applied to the mechanical elements interposed between the lens holder 11 and the rotating spacer 15.

[0084] In the embodiment, the AF drive unit 13 rotates the rotary spacer 15, and the end face cam 18 converts the rotary motion into linear motion to move the lens holder 11 in the optical axis direction, but the lens holder 11 may be moved in the optical axis direction while being rotated, that is, the lens holder 11 may function as a rotating body and perform a spiral motion. In this case, a mechanical element is provided between the lens holder 11 and the first stage 12.

[0085] Furthermore, the present invention can be applied not only to autofocus but also to zooming and other cases in which the first movable part (lens holder 11) is moved in the optical axis direction.

[0086] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0087] 1 Lens drive unit 10 OIS moving part (second moving part) 11 AF movable part, lens holder (first movable part) 11b Slide section 12 First stage (first fixed part) 13 AF drive unit (Z direction drive unit) 14 AF support part, upper spring (first support part) 15 Rotating spacer 15c Holder guide 16, 17 Ball 18 End cam (machine element) 20 OIS fixing part (second fixing part) 30 OIS drive unit (XY direction drive unit) 40 OIS support part (second support part)

Claims

1. A fixing part having an outer periphery having a shape surrounding a circular opening and on which wiring is arranged, the outer periphery having a recess that opens upward and is recessed downward and is provided in an arc shape along a circumferential direction; a ring-shaped rotating body disposed on the outer circumferential portion of the fixed portion, the rotating body having an annular portion extending along the circumferential direction and a protruding portion protruding downward from the annular portion at a position corresponding to the recess; a sliding support portion that supports sliding of the rotating body relative to the fixed portion at a position where the recess and the protrusion are provided; an ultrasonic motor fixed to the fixed portion on the outer circumferential side of the rotor, the ultrasonic motor having a piezoelectric element and a resonator, both of which are plate-shaped and have their plate surfaces bonded together; a power transmission section that is fixed to the rotor on an outer circumferential side of the rotor and is connected to the resonance section, the power transmission section having a length in a circumferential direction of the rotor, the resonating unit resonates with the vibration of the piezoelectric element that receives power via the wiring to generate a linear motion, and the power transmitting unit moves in the circumferential direction by the linear motion to rotate the rotating body. Rotary drive device.

2. The rotary drive device according to claim 1 , wherein the sliding support portion is a ball interposed between the fixed portion and the rotating body.

Images