Optical element driving device, camera module, and camera-mounted device

Abstract

Provided are an optical element driving device, a camera module, and a camera-equipped device which can achieve size reduction and height reduction and improve driving performance and sound-reducing performance.　This optical element driving device comprises: a fixed part; a movable part disposed apart from the fixed part; a support part which supports the movable part with respect to the fixed part; and a driving unit which has an ultrasonic motor that converts a vibration motion into a linear motion and a power transmission part that transmits the driving force of the ultrasonic motor to the movable part, and moves the movable part with respect to the fixed part, wherein the power transmission part has a plate which is in contact with a resonance part of the ultrasonic motor, and a damper material is disposed on a second surface side opposite to a first surface which is in contact with the resonance part in the plate.

Description

[Technical Field]

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

[0002] Generally, a small camera module is mounted on a mobile terminal such as a smartphone. Such a camera module employs an optical element driving device having an autofocus function (hereinafter referred to as "AF function") that automatically adjusts the focus when photographing a subject, and an image stabilization function (hereinafter referred to as "OIS function") that optically corrects shake (vibration) that occurs during photographing to reduce image distortion (see, for example, Patent Document 1).

[0003] The optical element driving device having AF and OIS functions includes an autofocus driving unit (hereinafter referred to as "AF driving unit") for moving a lens unit in the optical axis direction, and an image stabilization driving unit (hereinafter referred to as "OIS driving unit") for moving the lens unit in a plane perpendicular to the optical axis direction. In Patent Document 1, voice coil motors (VCMs) are used in the AF driving unit and the OIS driving unit.

[0004] In recent years, camera modules with multiple (typically two) optical element drivers have been put into practical use (so-called dual cameras). 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 still and moving images. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-210550 [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, an optical element driving device using a VCM is susceptible to external magnetism, which may impair high-precision operation. In particular, in a dual camera in which optical element driving devices are arranged side by side, there is a high possibility of magnetic interference occurring between the optical element driving devices.

[0007] Meanwhile, Patent Document 2 discloses an optical element driving device that uses ultrasonic motors in the AF driving unit and the OIS driving unit. The optical element driving device disclosed in Patent Document 2 is magnetless and can reduce the influence of external magnetism, but its structure is complex, making it difficult to reduce its size and height. Furthermore, in optical element driving devices, noise may be generated when the movable parts move to adjust focus or correct vibrations, and therefore quietness is required.

[0008] An object of the present invention is to provide an optical element driving device, a camera module, and a camera-mounted device that can be made smaller and thinner while also improving driving performance and noise reduction. [Means for solving the problem]

[0009] The optical element driving device according to the present invention comprises: A fixed portion; a movable portion disposed at a distance from the fixed portion; a support portion that supports the movable portion relative to the fixed portion; an ultrasonic motor that converts vibration motion into linear motion; and a drive unit that has a power transmission part that transmits a driving force of the ultrasonic motor to the movable part and moves the movable part relative to the fixed part, the power transmission unit has a plate that comes into contact with a resonance unit of the ultrasonic motor, A damper material is disposed on a second surface of the plate opposite to a first surface that contacts the resonating portion.

[0010] The camera module according to the present invention comprises: The optical element driving device; an optical element attached to the movable portion; and an imaging unit that captures the subject image formed by the optical element.

[0011] The camera-equipped device according to the present invention comprises: A camera-equipped device that is an information device or a transportation device, The above camera module, and an image processing unit that processes image information obtained by the camera module. [Effects of the Invention]

[0012] According to the present invention, it is possible to reduce the size and height of the optical element driving device, camera module, and camera-mounted device, and also improve the driving performance and noise reduction performance. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are diagrams showing a smartphone equipped with a camera module according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of the appearance of the camera module. [Figure 3] FIG. 3 is a perspective view of the optical element driving device. [Figure 4] FIG. 4 is a perspective view of the optical element driving device. [Figure 5] FIG. 5 is an exploded perspective view of the optical element driving device. [Figure 6] FIG. 6 is an exploded perspective view of the optical element driving device. [Figure 7] FIG. 7 is a plan view showing the wiring structure of the base. [Figure 8] FIG. 8 is an enlarged view of the OIS biasing member. [Figure 9] 9A and 9B are perspective views of the OIS drive unit. [Figure 10] FIG. 10 is an exploded perspective view of the OIS movable portion. [Figure 11] FIG. 11 is an exploded perspective view of the OIS movable portion. [Figure 12] FIG. 12 is an exploded perspective view of the OIS movable portion. [Figure 13] 13A and 13B are perspective views of the AF drive unit. [Figure 14] 14A and 14B are diagrams showing the holding structure of the AF drive unit. [Figure 15] FIG. 15 is a plan view of the OIS movable portion as seen from the light receiving side in the optical axis direction. [Figure 16] 16A and 16B are plan views of the AF movable portion and the first stage. [Figure 17] 17A and 17B are a horizontal cross-sectional view and a vertical cross-sectional view of the AF drive unit 14 and its surrounding area. [Figure 18] 18A and 18B are enlarged views showing the arrangement of the AF support parts. [Figure 19] 19A to 19C are diagrams showing the driving sound characteristics of the optical element driving device. [Figure 20] 20A and 20B are diagrams showing an automobile as a camera-mounted device equipped with an in-vehicle camera module. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0015] 1A and 1B are diagrams showing a smartphone M (an example of a camera-equipped 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.

[0016] The smartphone M has a dual camera system 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 shakes (vibrations) that occur during photography to capture images without blur.

[0017] Fig. 2 is a perspective view of the appearance of the camera module A. Figs. 3 and 4 are perspective views of the appearance of the optical element driving device 1 according to the embodiment. Fig. 4 shows a state in which Fig. 3 is rotated 180° around the Z axis. As shown in Figs. 2 to 4, the embodiment will be described using a Cartesian coordinate system (X, Y, Z). The same Cartesian coordinate system (X, Y, Z) is also used in the drawings that will be described later.

[0018] For example, when a photograph is actually taken 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, and the upper side (+Z side) in the drawing is the light-receiving side in the optical axis direction, and the lower side (-Z side) is the image-forming side in the optical axis direction. Furthermore, the X and Y directions perpendicular to the Z axis are referred to as "directions perpendicular to the optical axis," and the XY plane is referred to as the "plane perpendicular to the optical axis."

[0019] 2 to 4, the camera module A includes an optical element driving device 1 that realizes an AF function and an OIS function, a lens unit 2 formed by a cylindrical lens barrel containing a lens, and an imaging unit 3 that captures an image of a subject formed by the lens unit 2. In other words, the optical element driving device 1 is a so-called lens driving device that drives the lens unit 2 as an optical element.

[0020] The imaging unit 3 is arranged on the imaging side of the optical element driving device 1 in the optical axis direction. The imaging unit 3 includes, for example, an image sensor substrate 301, an imaging element 302 mounted on the image sensor substrate 301, and a control unit 303. The imaging element 302 is configured, for example, by a CCD (charge-coupled device) image sensor or a CMOS (complementary metal oxide semiconductor) image sensor, and captures the subject image formed by the lens unit 2. The control unit 303 is configured, for example, by a control IC, and controls the driving of the optical element driving device 1. The optical element driving device 1 is mounted on the image sensor substrate 301 and is mechanically and electrically connected thereto. The control unit 303 may be provided on the image sensor substrate 301, or may be provided in a camera-equipped device (in this embodiment, a smartphone M) in which the camera module A is mounted.

[0021] The optical element driving device 1 is covered on the outside with a cover 24. The cover 24 is a covered square cylinder that is rectangular in plan view when viewed from the optical axis direction. In this embodiment, the cover 24 has a square shape in plan view. The cover 24 has a substantially circular opening 241 on its upper surface. The lens unit 2 faces the outside through the opening 241 of the cover 24 and is configured to protrude beyond the opening surface of the cover 24 toward the light receiving side as the lens unit 2 moves in the optical axis direction, for example. The cover 24 is fixed to the base 21 (see FIG. 5) of the OIS fixing unit 20 of the optical element driving device 1 by, for example, adhesive.

[0022] 5 and 6 are exploded perspective views of the optical element driving device 1 according to the embodiment. Fig. 6 shows a state where Fig. 5 is rotated 180° around the Z axis. Fig. 5 shows a state where the OIS driving unit 30 and the sensor board 22 are attached to the base 21, and Fig. 6 shows a state where the OIS driving unit 30 and the sensor board 22 are removed from the base 21.

[0023] 5 and 6, in this embodiment, the optical element driving device 1 includes an OIS movable section 10, an OIS fixed section 20, an OIS driving unit 30, and an OIS support section 40. The OIS driving unit 30 has an X-direction driving unit 30X and a Y-direction driving unit 30Y.

[0024] The OIS movable part 10 is a part that moves within a plane perpendicular to the optical axis during shake correction. The OIS movable part 10 includes an AF unit, a second stage 13, and X-direction reference balls 42A to 42D (see FIG. 10, etc.). The AF unit has an AF movable part 11, a first stage 12, an AF drive unit 14, and an AF support part 15 (see FIGS. 10 to 12). The OIS fixing portion 20 is a portion to which the OIS movable portion 10 is connected via the OIS support portion 40. The OIS fixing portion 20 includes a base 21. 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. The OIS movable part 10 and the OIS fixed part 20 are biased in directions to move closer to each other by an OIS biasing member 50. The OIS biasing members 50 are disposed, for example, at the four corners of the optical element driving device 1 in a plan view.

[0025] In this embodiment, for movement in the Y direction, the entire OIS movable section 10 including the AF unit moves as a movable body. On the other hand, for movement in the X direction, only the AF unit moves as a movable body. In other words, for movement in the X direction, the second stage 13, together with the base 21, constitutes the OIS fixed section 20, and the X-direction reference balls 42A to 42C function as the OIS support section 40.

[0026] The base 21 is 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 a liquid crystal polymer. The base 21 is a rectangular member in a plan view, and has a circular opening 211 in the center.

[0027] The base 21 has a first base portion 212 and a second base portion 213 that form the main surfaces of the base 21. The second base portion 213 is provided to correspond to the portions of the OIS movable portion 10 that protrude toward the image-forming side in the optical axis direction, i.e., the protrusions 112A to 112D of the AF movable portion 11 and the AF motor fixing portion 125 of the first stage 12 (see FIG. 11). The second base portion 213 is formed to be slightly larger than the protrusions 112A to 112D and the AF motor fixing portion 125 in a plan view to prevent interference during shake correction. The sensor board 22 is disposed in an area of ​​the second base portion 213 where the terminal fittings 23B are disposed, with a portion of the sensor board 22 exposed. The second base portion 213 is recessed relative to the first base portion 212, thereby ensuring the movement stroke of the AF movable portion 11 and reducing the height of the optical element driving device 1.

[0028] In this embodiment, the sensor board 22 is provided in an area where the AF drive unit 14 and the OIS drive unit 30 are not disposed, i.e., an area corresponding to one side (fourth side) of the rectangular planar shape of the base 21. This allows the power supply lines and signal lines for the magnetic sensors 25X, 25Y, and 25Z to be consolidated, and the wiring structure in the base 21 can be simplified (see FIG. 7).

[0029] The base 21 has an OIS motor fixing portion 215 on which the Y-direction drive unit 30Y is disposed. The OIS motor fixing portion 215 is provided, for example, at a corner of the base 21, and is formed to protrude from the first base portion 212 toward the light-receiving side in the optical axis direction, and has a shape that can hold the Y-direction drive unit 30Y.

[0030] Terminal fittings 23A to 23C are arranged on the base 21 by, for example, insert molding. The terminal fitting 23A includes a power supply line to the AF drive unit 14 and the X-direction drive unit 30X. The terminal fitting 23A is exposed, for example, from the four corners of the base 21 and is electrically connected to the OIS biasing member 50. Power is supplied to the AF drive unit 14 and the X-direction drive unit 30X via the OIS biasing member 50. The terminal fitting 23B includes power supply lines (for example, four lines) and signal lines (for example, six lines) to the magnetic sensors 25X, 25Y, and 25Z. The terminal fitting 23B is electrically connected to wiring (not shown) formed on the sensor substrate 22. The terminal fitting 23C includes a power supply line to the Y-direction drive unit 30Y.

[0031] The base 21 also has Y-direction reference ball holding portions 217A to 217C on which the Y-direction reference balls 41A to 41C that make up the OIS support portion 40 are arranged. The Y-direction reference ball holding portions 217A to 217C are formed as rectangular recesses extending in the Y direction. The Y-direction reference ball holding portions 217A to 217C are formed so that their cross-sectional shape is approximately V-shaped (tapered) so that the groove width narrows toward the bottom side.

[0032] In this embodiment, the Y-direction reference ball holding portions 217A and 217B are provided on the side (third side) of the base 21 on which the Y-direction drive unit 30Y is arranged, and the Y-direction reference ball holding portion 217C is provided on the side (fourth side) on which the sensor substrate 22 is arranged, so that the OIS movable portion 10 (second stage 13) is supported at three points by the Y-direction reference balls 41A to 41C arranged on the Y-direction reference ball holding portions 217A to 217C.

[0033] The sensor substrate 22 has wiring (not shown) including power supply lines and signal lines for the magnetic sensors 25X, 25Y, and 25Z. The magnetic sensors 25X, 25Y, and 25Z are mounted on the sensor substrate 22. The magnetic sensors 25X, 25Y, and 25Z are configured, for example, with Hall elements or TMR (Tunnel Magneto Resistance) sensors, and are electrically connected to the terminal fittings 23B via wiring (not shown) formed on the sensor substrate 22. Furthermore, an opening 221 is provided in the sensor substrate 22 in a portion corresponding to the Y-direction reference ball holding portion 217C.

[0034] Magnets 16X and 16Y are disposed in positions facing the magnetic sensors 25X and 25Y on the first stage 12 of the OIS movable part 10 (see FIG. 12). The positions of the OIS movable part 10 in the X and Y directions are detected by a position detection unit consisting of the magnetic sensors 25X and 25Y and the magnets 16X and 16Y. Furthermore, in the AF movable part 11 of the OIS movable part 10, a magnet 16Z is disposed at a position facing the magnetic sensor 25Z (see FIG. 12). A position detection part consisting of the magnetic sensor 25Z and the magnet 16Z detects the position of the AF movable part 11 in the Z direction. Note that instead of the magnets 16X, 16Y, and 16Z and the magnetic sensors 25X, 25Y, and 25Z, an optical sensor such as a photoreflector may be used to detect the positions of the OIS movable part 10 in the X and Y directions and the position of the AF movable part 11 in the Z direction.

[0035] The OIS biasing member 50 is formed, for example, by a tension coil spring, and connects the OIS movable part 10 and the OIS fixed part 20. In the present embodiment, one end of the OIS biasing member 50 is connected to the terminal fitting 23A of the base 21, and the other end is connected to the wiring 17A, 17B of the first stage 12. That is, in the present embodiment, the OIS biasing member 50 functions as a power supply line to the AF drive unit 14 and the X-direction drive unit 30X. Furthermore, the OIS biasing member 50 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 movably within the XY plane while being biased in the optical axis direction (pressed against the base 21) by the OIS biasing member 50. This allows the OIS movable part 10 to be held in a stable state without rattle.

[0036] As shown in FIG. 8 , a damper material 71 is disposed to suppress vibration of the OIS biasing member 50. The damper material 71 is disposed, for example, so as to entirely cover the OIS biasing member 50. The damper material 71 also fills the hollow portion inside the OIS biasing member 50. The damper material 71 is formed, for example, after the OIS biasing member 50 is assembled, with the spring in a stretched state. The damper material 71 is formed of a gel-like resin material that can remain in the hollow portion of the OIS biasing member 50 and has viscosity and elasticity that do not impair the ability to follow the movement of the OIS movable part 10 in the XY plane. For example, a silicone material or a silicone-based vibration-damping material can be used as the damper material 71. The damper material 71 may be arranged so as to fill only the gaps between axially adjacent spring elements, or may be filled only inside the coil springs.

[0037] If the OIS biasing member 50 is made of a spring material, vibrations are likely to occur when the OIS movable part 10 moves within the XY plane. These vibrations are then transmitted through the air and are perceived as drive noise. In this embodiment, a damper material 71 is provided in the OIS biasing member 50, so that the vibrations of the OIS biasing member 50 are efficiently damped in a short time, and air vibrations associated with the vibrations of the OIS biasing member 50 are also suppressed. This makes it possible to suppress the generation of drive noise, significantly improving the quietness of the optical element driver 1.

[0038] The OIS support section 40 supports the OIS movable section 10 in a state where it is spaced apart in the optical axis direction from the OIS fixed section 20. In this embodiment, the OIS support section 40 includes three Y-direction reference balls 41A to 41C interposed between the OIS movable section 10 (second stage 13) and the base 21. Furthermore, the OIS support section 40 includes four X-direction reference balls 42A to 42D interposed between the first stage 12 and the second stage 13 in the OIS movable section 10 (see FIG. 10, etc.).

[0039] In this embodiment, by restricting the rolling directions of the Y-direction reference balls 41A to 41C and the X-direction reference balls 42A to 42D (seven in total), the OIS movable part 10 can be moved with precision within the XY plane. Note that the numbers of Y-direction reference balls and X-direction reference balls that make up the OIS support part 40 can be changed as appropriate.

[0040] The OIS driving unit 30 is an actuator that moves the OIS movable part 10 in the X and Y directions. Specifically, the OIS driving unit 30 is made up of an X-direction driving unit 30X that moves the OIS movable part 10 (AF unit only) in the X direction, and a Y-direction driving unit 30Y that moves the entire OIS movable part 10 in the Y direction. The X-direction drive unit 30X is fixed to an OIS motor fixing portion 124 along the X direction of the first stage 12 (see FIG. 11). The Y-direction drive unit 30Y is fixed to an OIS motor fixing portion 215 of the base 21 so as to extend along the Y direction. In other words, the X-direction drive unit 30X and the Y-direction drive unit 30Y are arranged along sides that are perpendicular to each other. The X-direction drive unit 30X and the Y-direction drive unit 30Y include an OIS ultrasonic motor USM1, as will be described later.

[0041] The configuration of the OIS drive unit 30 is shown in Figures 9A and 9B. Figure 9A shows the assembled state of the components of the OIS drive unit 30, and Figure 9B shows the disassembled state of the components of the OIS drive unit 30. Note that although Figures 9A and 9B show the Y-direction drive unit 30Y, the main configuration of the X-direction drive unit 30X, specifically the configuration except for the shape of the OIS electrodes 33, is similar, and therefore these figures are treated as showing the OIS drive unit 30.

[0042] 9A and 9B, the OIS driving unit 30 has an OIS ultrasonic motor USM1 and a power transmission unit 34. The OIS ultrasonic motor USM1 is composed of an OIS resonance unit 31, an OIS piezoelectric element 32, and an OIS electrode 33. The driving force of the OIS ultrasonic motor USM1 is transmitted to the second stage 13 via the OIS power transmission unit 34. Specifically, the X-direction driving unit 30X is connected to the second stage 13 via the OIS power transmission unit 34, and the Y-direction driving unit 30Y is connected to the second stage 13 via the OIS power transmission unit 34. That is, in the OIS driving unit 30, the OIS resonance unit 31 constitutes an active element, and the OIS power transmission unit 34 constitutes a passive element.

[0043] 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. Two OIS piezoelectric elements 32 are arranged so as to sandwich the body 311 of the OIS resonating unit 31. The OIS electrode 33 sandwiches the OIS resonating portion 31 and the OIS piezoelectric element 32 and applies a voltage to the OIS piezoelectric element 32. The OIS electrode 33 of the X-direction drive unit 30X is electrically connected to the wiring 17A of the first stage 12, and the OIS electrode 33 of the Y-direction drive unit 30Y is electrically connected to the terminal fitting 23C of the base 21.

[0044] The OIS resonator 31 is made of a conductive material and resonates with the vibration of the OIS piezoelectric element 32, converting the vibrational motion into linear motion. The OIS resonator 31 is formed, for example, by laser processing, etching, or pressing a metal plate. In this embodiment, the OIS resonator 31 has a substantially rectangular body 311 that is sandwiched between the OIS piezoelectric element 32, two arms 312 that extend in the X direction or Y direction from the top and bottom of the body 311, a protrusion 313 that extends in the X direction or Y direction from the center of the body 311, and a conductive part 314 that extends from the center of the body 311 to the side opposite to the protrusion 313. The two arm portions 312 have symmetrical shapes, and their free ends abut against the OIS power transmission unit 34, and deform symmetrically in resonance with the vibration of the OIS piezoelectric element 32. In this embodiment, the two arm portions 312 are formed so that the abutment surfaces that abut against the OIS plate 341 of the OIS power transmission unit 34 face inward and face each other. The current-carrying portion 314 of the X-direction drive unit 30X is electrically connected to the wiring 17A of the first stage 12, and the current-carrying portion 314 of the Y-direction drive unit 30Y is electrically connected to the terminal metal fitting 23C of the base 21.

[0045] The OIS piezoelectric element 32 is attached to the body 311 of the OIS resonator 31 in the thickness direction, and is sandwiched between the OIS electrodes 33, thereby electrically connecting them to each other. For example, one end of a power supply path is connected to the OIS electrode 33, and the other end is connected to the current-carrying portion 314 of the OIS resonator 31, so that a voltage is applied to the OIS piezoelectric element 32, causing it to vibrate.

[0046] 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 each of the two resonant frequencies. The different behaviors are a behavior that moves the OIS power transmission unit 34 forward in the X direction or the Y direction and a behavior that moves it backward.

[0047] The OIS power transmission unit 34 is a chucking guide that extends in one direction, with one end connected to the arm unit 312 of the OIS resonating unit 31 and the other end connected to the second stage 13. The OIS power transmission unit 34 has a stage connecting member 342 that is connected to the first stage 12 or the second stage 13, and a plate-shaped OIS plate 341 that connects the OIS ultrasonic motor USM1 (OIS resonating unit 31) and the stage connecting member 342.

[0048] Two OIS plates 341 are provided so as to abut against the two arm portions 312 of the OIS resonating unit 31, respectively. The two OIS plates 341 are arranged substantially parallel to each other. The surface of the OIS plate 341 that abuts against the OIS resonating unit 31 is referred to as the "first surface," and the opposite surface is referred to as the "second surface." The OIS plates 341 are arranged so that the second surfaces face each other. One end 341b of the OIS plate 341 (hereinafter referred to as the "OIS motor contact portion 341b") slidably contacts the free end of the arm portion 312 of the OIS resonating unit 31. The other end (reference number omitted) of the OIS plate 341 is inserted into and fixed to the stage connecting member 342. The portion of the OIS plate 341 that extends from the OIS motor contact portion 341b toward the other end is referred to as the "extension portion 341a."

[0049] The stage connecting member 342 is fixed to the OIS chucking guide fixing portion 135 (see FIG. 10, etc.) of the second stage 13. The stage connecting member 342 has a structure that, for example, clamps the base of the extending portion 341a of the OIS plate 341. This makes it possible to prevent the OIS plate 341 from shifting and falling off over time, improving reliability.

[0050] The width between the OIS motor contact portions 341b is set wider than the width between the free ends of the arm portions 312 of the OIS resonating unit 31. In this embodiment, the stage connecting member 342 has a separation portion 342a and a plate fixing portion 342b at a portion where the OIS plate 341 is connected. The plate fixing portion 342b is formed in a groove shape, and an end of the OIS plate 341 is inserted into the separation portion 342a. By making the width of the separation portion 342a wider than the width of the plate fixing portion 342b, the two extension portions 341a are positioned so as to move away from each other toward the OIS motor contact portions 341b, and the width between the OIS motor contact portions 341b is also increased. When the OIS power transmission unit 34 is attached between the arm portions 312 of the OIS resonating unit 31, the extension portion 341a functions as a leaf spring, and a biasing force acts in a direction that pushes the arm portions 312 apart. This biasing force holds the OIS power transmission unit 34 between the free ends of the arm units 312, and the driving force from the OIS resonating unit 31 is transmitted to the OIS power transmission unit 34 efficiently.

[0051] Since the OIS resonating part 31 and the OIS power transmission part 34 are only in contact with each other in a biased state, the movement stroke of the OIS movable part 10 can be lengthened by simply enlarging the contact part in the X direction or Y direction without increasing the external dimensions of the optical element driving device 1.

[0052] The X-direction drive unit 30X is fixed to the OIS movable part 10 (first stage 12) and connected to the second stage 13 via the OIS power transmission part 34, and moves together with the OIS movable part 10 when the Y-direction drive unit 30Y corrects shake in the Y direction. On the other hand, the Y-direction drive unit 30Y is fixed to the OIS fixed part 20 (base 21) and connected to the second stage 13 via the OIS power transmission part 34, and is not affected by shake correction in the X direction by the X-direction drive unit 30X. In other words, movement of the OIS movable part 10 by one OIS drive unit 30 is not hindered by the structure of the other OIS drive unit 30. Therefore, rotation of the OIS movable part 10 around the Z axis can be prevented, and the OIS movable part 10 can be moved with precision within the XY plane.

[0053] Furthermore, a damper material 72 is disposed between the two extension portions 341a. The damper material 72 is disposed, for example, after connecting the OIS power transmission unit 34 between the two arm portions 312 of the OIS resonating unit 31. The damper material 72 is formed of a gel-like resin material that can remain between the two extension portions 341a and has viscosity and elasticity that does not impede the movement of the OIS power transmission unit 34. For example, a silicone material or a silicone-based vibration-damping material can be used as the damper material 72.

[0054] The extension portion 341a is a plate-like portion that is prone to vibration due to the resonance of the OIS resonating portion 31. This vibration is then transmitted through the air and recognized as drive noise. In this embodiment, the damper material 72 is disposed between the two extension portions 341a, so that the vibration of the two extension portions 341a is efficiently damped in a short time, and air vibrations caused by vibration transmission from the opposing second surface are also suppressed. Therefore, the generation of drive noise can be suppressed, and the noise reduction performance of the optical element driving device 1 is significantly improved.

[0055] Furthermore, the damper material 72 is disposed only on the extending portion 341a of the OIS plate 341, and is not disposed on the OIS motor contact portion 341b. This makes it possible to suppress the effect of the damper material 72 on the contact state (sliding state) between the OIS motor contact portion 341b and the OIS resonating portion 31, and it is possible to obtain stable driving performance similar to when the damper material 72 is not provided.

[0056] 10 to 12 are exploded perspective views of the OIS movable part 10. FIG. 11 shows a state in which FIG. 10 has been rotated 180° around the Z axis. FIG. 12 is a bottom perspective view showing a state in which FIG. 10 has been rotated 180° around the Z axis. Note that in FIG. 11, the AF drive unit 14 and the X-direction drive unit 30X have been removed from the first stage 12. In the following, in the rectangular planar shape of the optical element driving device 1, the side on which the AF driving unit 14 is arranged will be referred to as the "first side," the side on which the X-direction driving unit 30X is arranged will be referred to as the "second side," the side on which the Y-direction driving unit 30Y is arranged will be referred to as the "third side," and the remaining side will be referred to as the "fourth side."

[0057] 10 to 12, in this embodiment, OIS movable section 10 has AF movable section 11, first stage 12, second stage 13, AF drive unit 14, AF support section 15, etc. With respect to movement in the Y direction, the entire OIS movable section 10 including first stage 12 and second stage 13 is a movable body, whereas with respect to movement in the X direction, second stage 13 functions as OIS fixed section 20, and only the AF unit (AF movable section 11 and first stage 12) functions as OIS movable section 10. In addition, first stage 12 functions as an AF fixed section that supports AF movable section 11.

[0058] The AF movable part 11 is a lens holder that holds the lens part 2 (see FIG. 2), and moves in the optical axis direction when focusing. The AF movable part 11 is disposed radially inward and spaced apart from the first stage 12 (AF fixed part), and is supported by the first stage 12 via the AF support part 15 in a state where it is biased against the first stage 12.

[0059] The AF movable part 11 is formed of, for example, polyarylate (PAR), a PAR alloy which is a mixture of multiple resin materials including PAR, a liquid crystal polymer, etc. The AF movable part 11 has a cylindrical lens housing part 111. The lens part 2 is fixed to the inner peripheral surface of the lens housing part 111 by, for example, adhesive.

[0060] The AF movable part 11 has protrusions 112A to 112D that protrude radially outward and extend in the optical axis direction on the outer circumferential surface of the lens housing part 111. The protrusions 112A to 112D protrude further toward the imaging side in the optical axis direction than the lower surface of the lens housing part 111 and abut against the second base part 213 of the base 21, thereby restricting movement of the AF movable part 11 toward the imaging side (downward) in the optical axis direction. In this embodiment, the protrusions 112A to 112D abut against the second base part 213 of the base 21 in a reference state in which the AF drive unit 14 is not driven.

[0061] Furthermore, a magnet housing portion 114 that houses a magnet 16Z for detecting the Z position is provided on the outer peripheral surface of the lens housing portion 111. The magnet 16Z is disposed in the magnet housing portion 114. A magnetic sensor 25Z for detecting the Z position is disposed on the sensor substrate 22 at a position facing the magnet 16Z in the optical axis direction (see FIG. 5).

[0062] The first stage 12 supports the AF movable section 11 via the AF support section 15. The second stage 13 is disposed on the imaging side of the first stage 12 in the optical axis direction via X-direction reference balls 42A to 42D. The first stage 12 moves in the X and Y directions during shake correction, and the second stage 13 moves only in the Y direction during shake correction.

[0063] The first stage 12 is a member having a substantially rectangular shape in a plan view seen from the optical axis direction, and is formed of, for example, a liquid crystal polymer. The first stage 12 has a substantially circular opening 121 in a portion corresponding to the AF movable part 11. The opening 121 has cutouts 122 corresponding to the protrusions 112A to 112D and the magnet housing part 114 of the AF movable part 11. The portion of the first stage 12 corresponding to the X-direction drive unit 30X (the outer surface of the side wall along the second side) is recessed radially inward (OIS motor fixing part 124) so ​​that the X-direction drive unit 30X can be disposed without protruding radially outward. Similarly, the portion of the first stage 12 corresponding to the Y-direction drive unit 30Y (the outer surface of the side wall along the third side) is also recessed radially inward.

[0064] The first stage 12 has, on its underside, X-direction reference ball holding portions 123A to 123D that hold the X-direction reference balls 42A to 42D. The X-direction reference ball holding portions 123A to 123D are formed as rectangular recesses extending in the X direction. The X-direction reference ball holding portions 123A to 123D face the X-direction reference ball holding portions 133A to 133D of the second stage 13 in the Z direction. The X-direction reference ball holding portions 123A and 123B are formed so that their cross-sections are approximately V-shaped (tapered) so that the groove width narrows toward the bottom side, and the X-direction reference ball holding portions 123C and 123D are formed so that they are approximately U-shaped.

[0065] An AF motor fixing section 125 is formed on one side wall of the first stage 12 along the X direction (the side wall along the first edge), on which an AF resonator 141, which is an active element of the AF drive unit 14, and the like, are disposed. The AF motor fixing section 125 has an upper fixing plate (reference numeral omitted) and a lower fixing plate 125a, between which the AF resonator 141 is sandwiched. The AF resonator 141 is inserted into insertion holes (reference numeral omitted) provided in the upper fixing plate and the lower fixing plate 125a and fixed by adhesive, for example. The upper fixing plate is formed by a part of the wiring 17B, and the AF resonator 141 is electrically connected to the wiring 17B.

[0066] Magnets 16X and 16Y for detecting X and Y positions are arranged on one side wall of the first stage 12 along the Y direction (the side wall along the fourth side). For example, the magnet 16X is magnetized in the X direction, and the magnet 16Y is magnetized in the Y direction. Magnetic sensors 25X and 25Y for detecting X and Y positions are arranged on the sensor substrate 22 at positions facing the magnets 16X and 16Y in the optical axis direction (see FIG. 5).

[0067] Furthermore, wiring 17A and 17B are embedded in the first stage 12 by, for example, insert molding. The wiring 17A and 17B are arranged, for example, along the first side and the second side. The wiring 17A and 17B are exposed from the four corners of the first stage 12, and one end of the OIS biasing member 50 is connected to this exposed portion. Power is supplied to the X-direction drive unit 30X via the wiring 17A, and to the AF drive unit 14 via the wiring 17B.

[0068] The second stage 13 is a member having a substantially rectangular shape in a plan view seen from the optical axis direction, and is made of, for example, a liquid crystal polymer. An inner peripheral surface 131 of the second stage 13 is formed to correspond to the outer shape of the AF movable part 11. In the second stage 13, portions corresponding to the X-direction drive unit 30X and the Y-direction drive unit 30Y (outer surfaces of the side walls along the second and third sides) are formed to be recessed radially inward, similar to the first stage 12.

[0069] The second stage 13 has, on its underside, Y-direction reference ball holding portions 134A to 134C that house the Y-direction reference balls 41A to 41C. The Y-direction reference ball holding portions 134A to 134C are formed as rectangular recesses extending in the Y direction. The Y-direction reference ball holding portions 134A to 134C face the Y-direction reference ball holding portions 217A to 217C of the base 21 in the Z direction. The Y-direction reference ball holding portions 134A and 134B are formed so that their cross-sections are approximately V-shaped (tapered) so that the groove width narrows toward the bottom side, and the Y-direction reference ball holding portion 134C is formed so that it is approximately U-shaped.

[0070] The second stage 13 also has, on its upper surface, X-direction reference ball holding portions 133A to 133D that house the X-direction reference balls 42A to 42D. The X-direction reference ball holding portions 133A to 133D are formed as rectangular recesses extending in the X direction. The X-direction reference ball holding portions 133A to 133D face the X-direction reference ball holding portions 123A to 123D of the first stage 12 in the Z direction. The X-direction reference ball holding portions 133A to 133D have a substantially V-shaped (tapered) cross section so that the groove width narrows toward the bottom surface. In this embodiment, the X-direction reference ball holding portions 133A and 133B are provided on the side (second side) of the second stage 13 where the X-direction drive unit 30X is arranged, and the X-direction reference ball holding portions 133C and 133D are provided on the side (first side) where the AF drive unit 14 is arranged, so that the first stage 12 is supported at four points by the X-direction reference balls 42A to 42D.

[0071] The Y-direction reference balls 41A to 41C that make up the OIS support part 40 are held in multi-point contact between the Y-direction reference ball holding parts 217A to 217C of the base 21 and the Y-direction reference ball holding parts 134A to 134C of the second stage 13. Therefore, the Y-direction reference balls 41A to 41C roll stably in the Y direction. Furthermore, the X-direction reference balls 42A to 42D are sandwiched in multi-point contact between the X-direction reference ball holding portions 133A to 133D of the second stage 13 and the X-direction reference ball holding portions 123A to 123D of the first stage 12. Therefore, the X-direction reference balls 42A to 42D roll stably in the X direction.

[0072] The AF support part 15 is a part that supports the AF movable part 11 with respect to the first stage 12 (AF fixed part). The AF support part 15 is composed of a first Z-direction reference ball 15A and a second Z-direction reference ball 15B. The first Z-direction reference ball 15A and the second Z-direction reference ball 15B are interposed between the AF movable part 11 and the first stage 12 in a rollable state. In this embodiment, the first Z-direction reference ball 15A and the second Z-direction reference ball 15B are each composed of a plurality of balls (two in this case) arranged side by side in the Z direction.

[0073] The AF drive unit 14 is an actuator that moves the AF movable part 11 in the Z direction. Like the OIS drive unit 30, the AF drive unit 14 is composed of an ultrasonic motor. The AF drive unit 14 is fixed to the AF motor fixing part 125 of the first stage 12 so that the arm part 141b extends in the Z direction. The AF drive unit 14 has an AF ultrasonic motor USM2 and an AF power transmission part 144.

[0074] The configuration of the AF drive unit 14 (excluding the AF power transmission section 144) is shown in Figures 13A and 13B. Figure 13A shows the assembled state of the AF drive unit 14, and Figure 13B shows the disassembled state of the AF drive unit 14. The configuration of the AF drive unit 14 is almost the same as that of the OIS drive unit 30. The overall configuration of the AF drive unit 14, including the AF power transmission section 144, will be described later.

[0075] The AF ultrasonic motor USM2 is composed of an AF resonator 141, an AF piezoelectric element 142, and an AF electrode 143. The driving force of the AF ultrasonic motor USM2 is transmitted to the AF movable part 11 via an AF power transmission part 144. That is, in the AF drive unit 14, the AF resonator 141 constitutes an active element, and the AF power transmission part 144 constitutes a passive element.

[0076] The AF piezoelectric element 142 is, for example, a plate-shaped element made of a ceramic material, and generates vibration when a high-frequency voltage is applied to it. Two AF piezoelectric elements 142 are arranged so as to sandwich the body portion 141a of the AF resonating unit 141. The AF electrode 143 sandwiches the AF resonating unit 141 and the AF piezoelectric element 142 and applies a voltage to the AF piezoelectric element 142 .

[0077] The AF resonating unit 141 is made of a conductive material and resonates with the vibration of the AF piezoelectric element 142 to convert the vibration motion into linear motion. The AF resonating unit 141 is formed, for example, by laser processing, etching, or pressing a metal plate. In this embodiment, the AF resonating unit 141 has a substantially rectangular body portion 141a that is sandwiched between the AF piezoelectric elements 142, two arm portions 141b that extend in the Z direction from the body portion 141a, a current-carrying portion 141d that extends in the Z direction from the center of the body portion 141a and is electrically connected to a power supply path (wiring 17B (upper fixing plate) of the first stage 12), and a stage fixing portion 141c that extends from the center of the body portion 141a to the opposite side from the current-carrying portion 141d. The two arm portions 141b have symmetrical shapes, and their free ends abut against the AF power transmission portion 144 and deform symmetrically in resonance with the vibration of the AF piezoelectric element 142. In this embodiment, the two arm portions 141b are formed so that the surfaces that abut against the AF plate 61 of the AF power transmission portion 144 face outward, and the free ends are arranged so as to be sandwiched between the AF plate 61.

[0078] An AF piezoelectric element 142 is attached to the body 141a of the AF resonating unit 141 in the thickness direction, and is sandwiched between the AF electrode 143, thereby electrically connecting them. When the current-carrying portion 141d of the AF resonating unit 141 and the AF electrode 143 are connected to the wiring 17B of the first stage 12, a voltage is applied to the AF piezoelectric element 142, causing it to vibrate.

[0079] The AF resonating unit 141 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 141 is set so that it deforms in a different manner for each of the two resonant frequencies.

[0080] 14A and 14B are diagrams showing the holding structure of the AF drive unit 14. FIG. 14B shows an exploded view of the holding structure of the AF drive unit 14. FIG. 15 is a plan view of the OIS movable portion 10 as seen from the light-receiving side in the optical axis direction. The second stage 13 is omitted from FIG. 15. FIGS. 16A and 16B are plan views of the AF movable portion 11 and the first stage 12. FIGS. 17A and 17B are horizontal and vertical cross-sectional views of the peripheral portion of the AF drive unit 14. FIG. 17A is a cross-sectional view taken along the CC arrow in FIG. 17B, and FIG. 17B is a cross-sectional view taken along the BB arrow in FIG. 15. FIGS. 18A and 18B are enlarged views showing the arrangement of the AF support portion 15.

[0081] As shown in Figures 14A, 14B, etc., the protrusions 112A and 112B of the AF movable part 11 are arranged to face each other in the X direction and form a space extending in the tangential direction of the lens housing part 111 (here, the X direction).

[0082] The protrusions 112A and 112B, together with the first stage 12, hold Z-direction reference balls 15A and 15B as the AF support part 15. One of the protrusions, 112A, is formed with a first Z-direction reference ball holding part 113a that houses the first Z-direction reference ball 15A. The other protrusion, 112B, is formed with a second Z-direction reference ball holding part 113b that houses the second Z-direction reference ball 15B. The first Z-direction reference ball holding part 113a and the second Z-direction reference ball holding part 113b are formed with a substantially V-shaped (tapered) cross section so that the groove width narrows toward the groove bottom.

[0083] In the AF movable section 11, the space formed by the protrusions 112A and 112B serves as a drive unit housing section 115 in which the AF drive unit 14 is disposed. The protrusions 112A and 112B have a plate housing section 115c on the surface opposite to the first and second Z-direction reference ball holding sections 113a and 113b. The AF power transmission section 144 and the biasing member 62, which are passive elements of the AF drive unit 14, are disposed in the plate housing section 115c.

[0084] The AF power transmission part 144 is a chucking guide having a predetermined length in the Z direction. In this embodiment, the AF power transmission part 144 is made up of two AF plates 61. Specifically, the AF plate 61 is interposed between the AF resonating part 141 and the biasing member 62 of the AF drive unit 14. The power of the AF resonating part 141 is transmitted to the AF movable part 11 via the AF plate 61.

[0085] The AF plate 61 is a hard, plate-like member made of a metal material such as titanium copper, nickel copper, or stainless steel. The AF plate 61 is arranged on the AF movable part 11 along the movement direction so that a first surface thereof abuts against the arm part 141b of the AF resonator 141, and is movable integrally with the AF movable part 11. The AF plate 61 is arranged in the plate accommodating part 115c of the AF movable part 11 and is physically locked thereto. Specifically, the guide insertion part 611 of the AF plate 61 is loosely fitted into the guide groove 115a provided in the AF movable part 11, and the fixing piece 612 is arranged between the bottom surface of the plate accommodating part 115c and the locking piece 115b, thereby fixing the AF movable part 11 to the AF movable part 11. The AF plate 61 only needs to be fixed to the AF movable part 11 so that it can follow the mounting state (individual differences in mounting position) of the AF resonator part 141, and it does not have to be glued, or it may be glued with an elastically deformable soft adhesive (e.g., silicone rubber).

[0086] Furthermore, a damper material 73 is disposed between the second surface (the surface opposite to the first surface) of the AF plate 61 and the opposing surface. Specifically, the damper material 73 is filled so as to embed the plate accommodating portion 115c in which the AF plate 61 is disposed. The damper material 73 is formed, for example, in a state in which the AF drive unit 14 is assembled. The damper material 72 is formed of a gel-like resin material that can remain in the plate accommodating portion 115c and has viscosity and elasticity such that the biasing force of the biasing member 62 is not impaired. For example, a silicone material or a silicone-based vibration-damping material can be used as the damper material 73.

[0087] The AF plate 61 is a plate-shaped part that is prone to vibration due to the resonance of the AF resonating unit 141. This vibration is then transmitted through the air and recognized as drive noise. In this embodiment, the damper material 73 is disposed in the plate housing unit 115c in which the AF plate 61 is disposed, so that the vibration of the AF plate 61 is efficiently damped in a short time, and air vibrations caused by vibration transmission from the second surface are also suppressed. Therefore, the generation of drive noise can be suppressed, and the noise reduction performance of the optical element driving device 1 is significantly improved.

[0088] The biasing member 62 is a member for biasing the AFAF plate 61 toward the arm portion 141b of the AF resonator 141, and has two spring portions 621. The spring portions 621 are configured to press the AF plate 61 against the arm portion 141b with the same biasing force. The biasing force of the spring portions 621 is not weakened by the damper material 73. The biasing member 62 is formed, for example, by sheet metal processing, and the spring portion 621 is composed of a leaf spring extending from the connecting portion 622. Specifically, the leaf spring of the spring portion 621 extends from the lower portion of the connecting portion 622 toward the negative Z-direction, and is formed by folding back outward in a hairpin shape and tilting inward with respect to the Z-direction.

[0089] The connecting portion 622 of the biasing member 62 is placed on the spring mounting portion 115d provided in the drive unit housing portion 115, and the spring portion 621 is disposed in the plate housing portion 115c, thereby fixing the biasing member 62 to the AF movable portion 11. The AF plate 61 is located in the hairpin portion of the biasing member 62 and is biased inward (toward the arm portion 141b) by the spring portion 621. The biasing member 62 is not bonded to the AF movable portion 11 so that it can follow the mounting position of the AF drive unit 14. In other words, the biasing member 62 is movable along the mounting surface of the drive unit housing portion 115, and when the AF drive unit 14 (AF resonator portion 141 and AF plate 61) is sandwiched between the biasing member 62 and the AF resonator portion 141, the biasing member 62 is held in a position where the biasing loads of the two spring portions 621 are equal. Note that the configuration of the biasing member 62 is merely an example and can be modified as appropriate. For example, an elastic body such as a coil spring or hard rubber may be used.

[0090] The first stage 12 is cut out in portions corresponding to the protrusions 112A and 112B of the AF movable part 11 and the space between them to form an AF motor fixing part 125. A first Z-direction reference ball holding part 127a and a second Z-direction reference ball holding part 127b are provided adjacent to both sides of the AF motor fixing part 125.

[0091] The first Z-direction reference ball holding portion 127a is formed along the tangential direction D1 of the lens housing portion 111 (see FIG. 18A). The inner surface (the surface on the AF motor fixing portion 125 side) of the first Z-direction reference ball holding portion 127a is formed so that its cross section has a substantially V-shape (tapered shape) such that the groove width narrows toward the groove bottom.

[0092] The second Z-direction reference ball holding portion 127b is formed so as to be inclined with respect to the tangent direction D1 of the lens housing portion 111 (see FIG. 18B). The inner surface (the surface on the AF motor fixing portion 125 side) of the second Z-direction reference ball holding portion 127b has a substantially U-shaped cross section. The second Z-direction reference ball holding portion 127b is provided with the second Z-direction reference ball 15B and a biasing portion 18 (a leaf spring 181 and a spacer 182) for biasing the AF movable portion 11 via the second Z-direction reference ball 15B. FIG. 16B shows a state in which the leaf spring 181 is removed.

[0093] The second Z-direction reference ball 15B is biased obliquely with respect to the tangential direction D1 of the lens housing portion 111 (see FIG. 18B). As a result, the AF movable portion 11 is biased in two orthogonal directions, the X direction and the Y direction, via the second Z-direction reference ball 15B, and is held in a stable position within a plane perpendicular to the optical axis. If the angle between the tangential direction D1 and the biasing direction D2 is θ and the preload of the leaf spring 181 is F, the biasing force in the Y direction is F1 = F sin θ, and the biasing force in the X direction is F2 = F cos θ.

[0094] Here, the angle θ between the tangential direction D1 and the biasing direction D2 is, for example, 0° to 45° (excluding 0°). The biasing direction D2 is set, for example, in consideration of the preload F so that rotation of the AF movable part 11 around the optical axis is restricted. For example, if the angle θ between the biasing direction D2 and the tangential direction D1 is increased, the pressing force in the Y direction increases, so the preload F of the leaf spring 181 can be reduced, but this is disadvantageous in terms of space, as it requires increasing the protrusion length of the protrusions 112A and 112B. Conversely, if the angle θ between the biasing direction D2 and the tangential direction D1 is reduced, it is advantageous in terms of space, but the pressing force in the Y direction decreases, so the preload of the leaf spring 181 must be increased.

[0095] A first Z-direction reference ball 15A is held in a rollable state between the AF movable part 11 and the first Z-direction reference ball holders 113a, 127a of the first stage 12. Furthermore, a second Z-direction reference ball 15B is held in a rollable state between a spacer 182 arranged on the second Z-direction reference ball holder 127b of the first stage 12 and the second Z-direction reference ball holder 113b of the AF movable part 11. The AF movable part 11 is supported in a biased state by the first stage 12 via the first Z-direction reference ball 15A and the second Z-direction reference ball 15B, and is held in a stable posture.

[0096] The first Z-direction reference ball 15A is sandwiched between the AF movable part 11 and the first stage 12, and movement in the direction perpendicular to the optical axis (rotation of the AF movable part 11) is restricted. This allows the AF movable part 11 to move in the optical axis direction with stable behavior.

[0097] On the other hand, the second Z-direction reference ball 15B is sandwiched between the AF movable part 11 and the first stage 12 via a leaf spring 181 and a spacer 182, and is allowed to move in a direction perpendicular to the optical axis. This makes it possible to absorb the dimensional tolerances of the AF movable part 11 and the first stage 12, and improves the stability when the AF movable part 11 moves.

[0098] Furthermore, the portion where the AF drive unit 14 is disposed is sandwiched between the first Z-direction reference ball 15A and the second Z-direction reference ball 15B, and a preload is applied to the second Z-direction reference ball 15B. In other words, the AF movable part 11 is supported at one location relative to the first stage 12. This facilitates shortening the distance from the point of application of the drive force of the AF drive unit 14 to the rotation axis, thereby reducing the moment and preload. Furthermore, by having the second Z-direction reference ball 15B function as a preload ball, rolling resistance can be reduced. This improves the drive efficiency of the AF drive unit 14, making it suitable as a lens drive device for large-diameter lenses. Furthermore, for the same preload, tilt resistance is improved.

[0099] Each of the first Z-direction reference balls 15A and the second Z-direction reference balls 15B is made up of two balls, which reduces the rolling resistance of the first Z-direction reference balls 15A and the second Z-direction reference balls 15B compared to when they are made up of three or more balls.

[0100] In the optical element drive device 1, when a voltage is applied to the AF drive unit 14, the AF piezoelectric element 142 vibrates, and the AF resonator 141 deforms in a manner that corresponds to the frequency. The driving force of the AF drive unit 14 causes the AF power transmission unit 144 to slide in the Z direction. Accordingly, the AF movable unit 11 moves in the Z direction, and focusing is performed. Because the AF support unit 15 is formed of a ball, the AF movable unit 11 can move smoothly in the Z direction. Furthermore, because the AF drive unit 14 and the AF power transmission unit 144 are only in contact with each other in a biased state, simply increasing the size of the contact portion in the Z direction can easily increase the movement stroke of the AF movable unit 11 without compromising the low profile of the optical element drive device 1.

[0101] In the optical element driving device 1, when a voltage is applied to the OIS driving unit 30, the OIS piezoelectric element 32 vibrates, and the OIS resonating portion 31 deforms in a manner that corresponds to the frequency. The driving force of the OIS driving unit 30 causes the OIS power transmission portion 34 to slide in the X or Y direction. As a result, the OIS movable portion 10 moves in the X or Y direction, thereby performing shake correction. Because the OIS support portion 40 is made up of a ball, the OIS movable portion 10 can move smoothly in the X or Y direction.

[0102] Specifically, when the X-direction drive unit 30X is driven and the OIS power transmission section 34 moves in the X direction, power is transmitted from the first stage 12, on which the X-direction drive unit 30X is disposed, to the second stage 13. At this time, the ball 41 sandwiched between the second stage 13 and the base 21 cannot roll in the X direction, so the position of the second stage 13 in the X direction relative to the base 21 is maintained. On the other hand, the ball 42 sandwiched between the first stage 12 and the second stage 13 can roll in the X direction, so the first stage 12 moves in the X direction relative to the second stage 13. In other words, the second stage 13 constitutes the OIS fixed section 20, and the first stage 12 constitutes the OIS movable section 10.

[0103] Furthermore, when the Y-direction drive unit 30Y is driven and the OIS power transmission section 34 moves in the Y direction, power is transmitted from the base 21 on which the Y-direction drive unit 30Y is disposed to the second stage 13. At this time, the ball 42 sandwiched between the first stage 12 and the second stage 13 cannot roll in the Y direction, so the position of the first stage 12 in the Y direction relative to the second stage is maintained. On the other hand, the ball 41 sandwiched between the second stage 13 and the base 21 can roll in the Y direction, so the second stage 13 moves in the Y direction relative to the base 21. The first stage 12 also moves in the Y direction following the second stage 13. In other words, the base 21 constitutes the OIS fixed section 20, and the AF unit including the first stage 12 and the second stage 13 constitutes the OIS movable section 10.

[0104] In this way, the OIS movable part 10 moves within the XY plane, and shake correction is performed. Specifically, the voltage applied to the OIS drive units 30X and 30Y 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 results of an XY position detection part composed of magnets 16X and 16Y and magnetic sensors 25X and 25Y.

[0105] 19A to 19C are diagrams showing the driving sound characteristics of the optical element driving device 1 after the OIS driving unit 30 has been driven for a predetermined time (for example, 30 msec). Figure 19A shows a case where damper materials 71 to 73 are not provided, Figure 19B shows a case where damper material 71 is provided only in the OIS biasing member 50, and Figure 19C shows a case where damper materials 71 and 72 are provided in the OIS biasing member 50 and the OIS power transmission section 34. 19A and 19B indicates the silencing effect provided by damper material 71, and the difference between FIG. 19B and FIG. 19C indicates the silencing effect provided by damper material 72. That is, it can be seen that by providing damper material 71 in OIS biasing member 50, the sound pressure level of the drive sound is rapidly attenuated and reverberation is reduced. A similar silencing effect is obtained when damper material 72 is provided in OIS power transmission unit 34. Note that, although not shown, a similar silencing effect is obtained when damper material 73 is provided in AF power transmission unit 144.

[0106] As described above, the optical element driving device 1 according to this embodiment includes a fixed part, a movable part spaced apart from the fixed part, a support part that supports the movable part relative to the fixed part, an ultrasonic motor that converts vibrational motion into linear motion, and a drive unit that has a power transmission part that transmits the driving force of the ultrasonic motor to the movable part and moves the movable part relative to the fixed part. The power transmission part has a plate that abuts against a resonating part of the ultrasonic motor, and a damper material is arranged on a second surface of the plate that is opposite to the first surface that abuts against the resonating part.

[0107] That is, the optical element driving device 1 includes an OIS fixed section 20 (first fixed section), an OIS movable section 10 (first movable section) arranged spaced apart from the OIS fixed section 20 in the optical axis direction, an OIS support section 40 (support section) that supports the OIS movable section 10 relative to the OIS fixed section 20, and an OIS drive unit 30 (first drive unit) that has an OIS ultrasonic motor USM1 and an OIS power transmission section 34 and moves the OIS movable section 10 in a plane perpendicular to the optical axis direction relative to the OIS fixed section 20. The OIS power transmission section 34 has an OIS plate 341 that abuts against the OIS resonating section 31 of the OIS ultrasonic motor USM1, and a damper material 72 is arranged on a second surface of the OIS plate 341 opposite to the first surface that abuts against the OIS resonating section 31. Specifically, the OIS resonating section 31 has two arm sections 312 formed so that their contact surfaces with the OIS plate 341 face each other, two OIS plates 341 are provided so as to contact the two arm sections 312 respectively, and the damper material 72 is arranged between the two OIS plates 341.

[0108] The optical element driving device 1 also includes a first stage 12 (second fixed portion), an AF movable portion 11 (second movable portion) arranged inwardly and spaced apart from the first stage 12, an AF support portion 15 (support portion) that supports the AF movable portion 11 relative to the first stage 12, and an AF drive unit 14 (second drive unit) that has an AF ultrasonic motor USM2 and an AF power transmission portion 144 and moves the AF movable portion 11 in the optical axis direction relative to the first stage 12. The AF power transmission portion 144 has an AF plate 61 that abuts against the AF resonator portion 141 of the AF ultrasonic motor USM2, and a damper material 73 is arranged between a second surface of the AF plate 61 opposite to the first surface that abuts against the AF resonator portion 141 and the opposing surface. Specifically, the AF resonator has two arm portions 141b formed so that the abutment surfaces with the AF plate 61 face opposite sides, and two AF plates 61 are provided to abut against the two arm portions 141b, respectively, and are arranged between the damper material 73, each of the two AF plates 61, and the plate accommodating portion 115c in which the AF plates 61 are arranged.

[0109] According to the optical element driving device 1, the OIS driving unit 30 and the AF driving unit 14 are configured with ultrasonic motors, which reduces the influence of external magnetism and enables miniaturization and a low profile. As in a smartphone M, even if camera modules A having the optical element driving device 1 are placed close to each other, there is no magnetic influence, making it extremely suitable for dual cameras.

[0110] Furthermore, according to the optical element driving device 1, the damper material 72 efficiently damps the vibrations of the OIS plate 341 that accompany the driving of the OIS ultrasonic motor USM1, thereby suppressing air vibrations caused by the transmission of vibrations from the OIS plate 341. Furthermore, the damper material 73 efficiently damps the vibrations of the AF plate 61 that accompany the driving of the AF ultrasonic motor USM2, thereby suppressing air vibrations caused by the transmission of vibrations from the AF plate 61. Therefore, according to the optical element driving device 1, noise reduction performance is significantly improved.

[0111] 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 thereof.

[0112] For example, in the embodiment, a smartphone M, which is a camera-equipped mobile terminal, has been described as an example of a camera-equipped device equipped with a camera module A, but the present invention can be applied to any camera-equipped device having a camera module and an image processing unit that processes image information obtained by the camera module. Camera-equipped devices include information devices and transportation equipment. Information devices include, for example, camera-equipped mobile phones, notebook computers, tablet terminals, portable game consoles, web cameras, and camera-equipped in-vehicle devices (e.g., backup monitor devices, drive recorder devices). Furthermore, transportation equipment includes, for example, automobiles.

[0113] 20A and 20B are diagrams showing an automobile V as a camera-mounted device equipped with an in-vehicle camera module VC (Vehicle Camera). FIG. 20A is a front view of the automobile V, and FIG. 20B 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. 20A and 20B, 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 backup monitoring, drive recorders, collision avoidance control, autonomous driving control, etc.

[0114] In the embodiment, the damper materials 72 and 73 are provided in the OIS power transmission section 34 and the AF power transmission section 144, respectively, but they may be provided in either one of them. Furthermore, the present invention is not limited to optical element driving devices equipped with drive units for autofocus or shake correction, but can also be applied to optical element driving devices that use ultrasonic motors to move a movable part relative to a fixed part, and for example, a damper material may be placed in a drive unit for zooming.

[0115] Furthermore, in the embodiment, the optical element driving device 1 that drives the lens portion 2 as an optical element has been described, but the optical element to be driven may be an optical element other than a lens, such as a mirror or a prism.

[0116] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0117] The disclosures of the specification, drawings, and abstract contained in U.S. Provisional Application No. 63 / 109,385, filed November 4, 2020, are incorporated herein by reference in their entirety. [Explanation of symbols]

[0118] 1 Optical element driving device 10 OIS moving part (1st moving part) 12 First stage (second fixed part) 13 Second Stage 14 AF drive unit (second drive unit) 141 AF resonator (active element) 142 AF piezoelectric element 143 AF electrode 144 AF power transmission unit (passive element) 15 AF support part (second support part) 15A First Z-direction reference ball 15B Second Z-direction reference ball 20 OIS fixed part (1st fixed part) 21 Base 30 OIS drive unit 31 OIS resonator (active element) 32 OIS piezoelectric element 33 OIS electrode 34 OIS power transmission unit (passive element) 341 OIS Plate 40 OIS support part (1st support part) 50 OIS biasing member 61 AF Plate 62 biasing member 71~73 Damper material A Camera module M Smartphone (camera-equipped device)

Claims

1. A fixed portion; a movable portion disposed at a distance from the fixed portion; a support portion that supports the movable portion relative to the fixed portion; an ultrasonic motor that converts vibration motion into linear motion; and a drive unit that has a power transmission part that transmits a driving force of the ultrasonic motor to the movable part and moves the movable part relative to the fixed part, the power transmission unit has a plate that comes into contact with a resonance unit of the ultrasonic motor, a damper material is disposed on a second surface of the plate opposite to a first surface that contacts the resonating portion; Optical element driver.

2. the fixing portion includes a first fixing portion, the movable portion includes a first movable portion disposed apart from the first fixed portion in the optical axis direction, the drive unit includes a first drive unit that moves the first movable portion relative to the first fixed portion within an optical axis perpendicular plane that is perpendicular to the optical axis direction, the resonating unit has two arms formed so that their contact surfaces with the plate face each other, two plates are provided so as to abut against the two arms, respectively; The damper material is disposed between the two plates. The optical element driving device according to claim 1 .

3. the fixing portion includes a second fixing portion, the movable portion includes a second movable portion disposed inwardly and spaced apart from the second fixed portion, the drive unit includes a second drive unit that moves the second movable portion in the optical axis direction relative to the second fixed portion, the resonating portion has two arms formed so that their contact surfaces with the plate face in opposite directions, Two plates are provided so as to abut on the two arms, respectively, The damper material is disposed between each of the two plates and a plate accommodating portion in which the plate is disposed. The optical element driving device according to claim 1 .

4. the plate has a motor abutment portion that abuts against the resonating portion and an extension portion that extends from the motor abutment portion, The damper material is disposed in the extension portion. The optical element driving device according to claim 2 .

5. The optical element driving device according to any one of claims 1 to 4, an optical element attached to the movable portion; an imaging unit that captures a subject image formed by the optical element, Camera module.

6. A camera-equipped device that is an information device or a transportation device, The camera module according to claim 5; an image processing unit that processes image information obtained by the camera module, Camera-equipped device.

Images