Method of operation and controller for a drive unit

Abstract

The method of operation of the drive unit includes a step of generating a pulse block based on the drive pulse, and a step of correcting the drive signal in correspondence with the position error signal. In the step of correcting the drive signal, in a case where the position error signal is within a first range, the shape of the drive pulse is corrected in a manner such that the shape of the drive pulse becomes a first drive pulse shape, and a pulse block duty ratio is set to a first pulse block duty ratio value (C-83, C-84), and in a case where the position error signal is within a second range, the shape of the drive pulse is corrected in a manner such that the shape of the drive pulse becomes a second drive pulse shape, and the pulse block duty ratio is set to a second pulse block duty ratio value (C-85, C-86).

Description

Technical Field

[0001] This invention relates to the field of small drive devices such as piezoelectric drive devices. More specifically, this invention relates to the method of operating the drive unit and the controller described in the preamble of the corresponding independent claim. Background Technology

[0002] For example, small drive devices such as piezoelectric drive devices are disclosed in Patent Documents 1, 2, and 3. Such drive devices have one, two, or more vibrating arms that drive a passive element through vibrational motion at the ends of the arms. The frequency of the excitation unit driving the vibrational motion is selected in a manner that generates a vibrational mode in which the arms move the passive element in a first direction or a second direction opposite to it. Further improvements to the drive device are needed to take into account its inherent nonlinear characteristics in the design, particularly to control the position of the passive element relative to the active element.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2006 / 000118

[0006] Patent Document 2: U.S. Patent No. 7,429,812

[0007] Patent Document 3: International Publication No. 2019 / 068708 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] The purpose of this invention is to provide a method for operating a drive unit capable of position control of a drive unit of the above type, and a controller for controlling the operation of the drive unit.

[0010] Solution to the problem

[0011] The above objective is achieved by the driving unit's operation method and controller as described in the claims.

[0012] The method of operating the driving unit of the present invention is a method for operating the driving unit, wherein the driving unit drives a passive element relative to an active element, and in this method,

[0013] The active element comprises: a resonator and at least one excitation unit that excites the vibration of the resonator.

[0014] The resonator has at least one arm extending from the connecting portion of the resonator.

[0015] The at least one arm has a contact portion at its outer end.

[0016] The contact portion is movable by the vibrational movement of the at least one arm.

[0017] The contact portion includes a first contact portion.

[0018] The passive element is configured to move relative to the active element, driven by the vibrational motion.

[0019] The passive element has a first contact area, which is configured to contact the first contact portion.

[0020] The active element and the passive element are configured such that, when the active element is not activated, at least the first contact portion is pressed against the first contact area due to prestress.

[0021] The operation method of the drive unit includes the following steps:

[0022] The step of driving the excitation unit with a driving signal and repeatedly omitting the driving pulse to generate a periodically repeating pulse block, wherein the driving signal is a periodic signal containing the driving pulse repeated at the excitation frequency, and the relationship between the pulse block on-time Ton and the pulse block period Tb, Ton / Tb, is used as the pulse block duty cycle; and

[0023] The step of correcting the drive signal in accordance with the position error signal.

[0024] In the step of correcting the drive signal,

[0025] When the position error signal is within a first range, the pulse block duty cycle is set to a first pulse block duty cycle value and corrected as follows: the shape of the drive pulse is corrected to make the shape of the drive pulse conform to the shape of the first drive pulse, or the excitation frequency is corrected according to a first excitation frequency offset value.

[0026] When the position error signal is within the second range, the pulse block duty cycle is set to the second pulse block duty cycle value and corrected as follows: the shape of the drive pulse is corrected in such a way that the shape of the drive pulse becomes the shape of the second drive pulse, or the excitation frequency is corrected according to the second excitation frequency offset value.

[0027] The controller of the present invention is a controller configured to execute the operation method of the drive unit described above.

[0028] The controller is connected to the excitation unit of the drive unit and supplies power to the excitation unit, reads signals from the sensor and determines the position of the drive unit. Attached Figure Description

[0029] Figure 1A , Figure 1B This is a diagram showing a smartphone equipped with a camera module according to one embodiment of the present invention.

[0030] Figure 2 This is a 3D view of the camera module.

[0031] Figure 3A , Figure 3B This is a perspective view of the lens driving device according to the first embodiment.

[0032] Figure 4 This is an exploded perspective view of the lens driving device according to the first embodiment.

[0033] Figure 5 This is an exploded perspective view of the lens driving device according to the first embodiment.

[0034] Figure 6A , Figure 6B This is a 3D view of the OIS driver unit.

[0035] Figure 7 This is an exploded perspective view of the movable part of the OIS according to the first embodiment.

[0036] Figure 8 This is an exploded perspective view of the movable part of the OIS according to the first embodiment.

[0037] Figure 9 This is an exploded perspective view of the movable part of the OIS according to the first embodiment.

[0038] Figure 10A , Figure 10B This is a perspective view of the AF drive unit according to the first embodiment.

[0039] Figure 11A , Figure 11B This diagram shows the state after the first unit, AF drive unit, and AF support unit of the first embodiment are assembled.

[0040] Figure 12A , Figure 12B This is a perspective view of the lens driving device according to the second embodiment.

[0041] Figure 13 This is an exploded perspective view of the movable part of the OIS in the second embodiment.

[0042] Figure 14This is an exploded perspective view of the movable part of the OIS in the second embodiment.

[0043] Figure 15 This is an exploded perspective view of the movable part of the OIS in the second embodiment.

[0044] Figure 16A , Figure 16B This diagram shows the state after the first unit, AF drive unit, and AF support unit of the second embodiment are assembled.

[0045] Figure 17 This is a diagram of a drive unit used for vibration actuation.

[0046] Figure 18A , Figure 18B This is a diagram of a drive unit used for vibration actuation.

[0047] Figure 19 This is a diagram of a drive unit used for vibration actuation.

[0048] Figure 20 This is a diagram showing the drive signal when the shape of the drive pulse is adjusted, and the resulting vibration amplitude.

[0049] Figure 21 This is a diagram showing the drive signal when the presence of the drive pulse is adjusted, and the resulting vibration amplitude.

[0050] Figure 22 It is a graph showing the dependence of the drive speed v on the pulse duty cycle dp.

[0051] Figure 23 It is a graph showing the dependence of the driving speed v on the excitation frequency f.

[0052] Figure 24 This is a flowchart representing the driving method of the driving unit.

[0053] Figure 25A , Figure 25B This is a diagram of a car that serves as a camera mounting device equipped with a vehicle-mounted camera module. Detailed Implementation

[0054] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0055] [First Implementation Method]

[0056] Figure 1A , Figure 1B This is a diagram showing a smartphone M (an example of a camera mounting device) equipped with a camera module A according to one embodiment of the present invention. Figure 1A This is the main view of the smartphone M. Figure 1BThis is the rear view of the smartphone M.

[0057] The smartphone M has a dual-lens camera consisting of two rear cameras, OC1 and OC2. In this embodiment, camera module A is used in the rear cameras OC1 and OC2.

[0058] Camera module A features AF (Automatic Focus) and OIS (Optical Image Stabilization) functions, enabling it to automatically focus on the subject during shooting and optically correct for shake (vibration) during shooting to capture a clear image.

[0059] Figure 2 This is a 3D view of the camera module A. Figure 3A , Figure 3B This is a perspective view of the lens driving device 1 according to the first embodiment. Figure 3B Showing will Figure 3A The state after rotating 180° around the Z-axis. (Example) Figure 2 , Figure 3A and Figure 3B As shown, in this embodiment, an orthogonal coordinate system (X, Y, Z) is used for illustration. The same orthogonal coordinate system (X, Y, Z) is also used for illustration in the figures described later.

[0060] For example, a camera module A is installed such that, when the smartphone M is actually taking a picture, the X direction becomes the up-down direction (or left-right direction), the Y direction becomes the left-right direction (or up-down direction), and the Z direction becomes the front-back direction. That is, the Z direction is the optical axis direction, the upper side (+Z side) in the diagram is the light-receiving side along the optical axis, and the lower side (-Z side) is the imaging side along the optical axis. In addition, the X and Y directions, which are orthogonal to the Z axis, are called "orthogonal optical axis directions", and the XY plane is called the "orthogonal optical axis plane".

[0061] like Figure 2 , Figure 3A and Figure 3B As shown, the camera module A includes a lens drive device 1 that enables AF and OIS functions, a lens section 2 that houses the lens in a cylindrical lens tube, an imaging section (not shown) that captures the image of the subject imaged through the lens section 2, and a cover 3 that covers the entire module.

[0062] The cover 3 is a rectangular, covered, tetrahedral cylindrical body that appears rectangular when viewed from above in the direction of the optical axis. In this embodiment, the cover 3 is square when viewed from above. The cover 3 has a generally circular opening 3a on its upper surface. The lens portion 2 faces outward from the opening 3a and is configured to protrude towards the light-receiving side from the opening surface of the cover 3 as it moves in the direction of the optical axis. The cover 3 is fixed, for example, to the base 21 of the OIS fixing portion 20 of the lens drive device 1 by adhesive bonding (see reference). Figure 4 ).

[0063] The camera unit (not shown) is disposed on the imaging side along the optical axis of the lens driving device 1. The camera unit (not shown) includes, for example, an image sensor substrate and an imaging element mounted on the image sensor substrate. The imaging element is, for example, a CCD (charge-coupled device) type image sensor or a CMOS (complementary metal-oxide semiconductor) type image sensor. The imaging element captures an image of the subject imaged by the lens unit 2. The lens driving device 1 is mounted on the image sensor substrate (not shown) and is mechanically and electrically connected to it. The control unit that drives the lens driving device 1 can be disposed on the image sensor substrate or on a camera-mounted device (in this embodiment, a smartphone M) that mounts the camera module A.

[0064] Figure 4 , Figure 5 This is an exploded perspective view of the lens driving device 1 according to the first embodiment. Figure 5 Showing will Figure 4 The state after rotating 180° around the Z-axis.

[0065] like Figure 4 , Figure 5 As shown, in this embodiment, the lens driving device 1 includes an OIS movable part 10 (second movable part), an OIS fixing part 20 (second fixing part), an OIS driving part 30 (XY direction driving part), and an OIS support part 40 (second support part). Furthermore, Figure 5 In the diagram, the portion of the wiring 24 embedded in the base 21 is indicated by a dashed line.

[0066] The OIS movable part 10 is the portion that swings within the orthogonal plane of the optical axis during jitter correction. The OIS movable part 10 includes an AF unit, a second stage 13, and a ball bearing 42. The AF unit includes an AF movable part 11 (first movable part), a first stage 12 (first fixed part), an AF drive part 14 (Z-direction drive part), and an AF support part 15 (first support part) (see reference). Figures 7-9 ).

[0067] The OIS fixing part 20 is the part that connects to the OIS movable part 10 via the OIS support part 40. The OIS fixing part 20 includes a base 21.

[0068] The movable part 10 of the OIS is spaced apart from the fixed part 20 of the OIS in the optical axis direction and is connected to the fixed part 20 of the OIS through the OIS support part 40. In addition, the OIS movable part 10 and the fixed part 20 of the OIS are subjected to force by the OIS force-applying members 50 provided at the four corners in the direction that brings them closer together.

[0069] Furthermore, in this embodiment, regarding movement in the Y direction, the entire OIS movable part 10, including the AF unit, moves as a movable body. On the other hand, regarding movement in the X direction, only the AF unit moves as a movable body. That is, regarding movement in the X direction, the second unit 13 and the base 21 together constitute the OIS fixing part 20, and the ball bearing 42 functions as the OIS support part 40.

[0070] The base 21 is a rectangular component when viewed from above, formed from a molding material, and has a circular opening 21a in the center. The molding material includes, for example, polyarylate (PAR), PAR alloy (PAR / PC) made of a mixture of various resin materials including PAR, or liquid crystal polymer.

[0071] The base 21 has a first base portion 21b forming the main surface of the base 21 and a second base portion 21c formed at one of the four corners, with a recess formed between the first base portion 21b and the second base portion 21c. A sensor substrate 22 is disposed in this recess, and the first base portion 21b, the second base portion 21c and the sensor substrate 22 form an aligned base surface.

[0072] The base 21 has an OIS motor fixing part 21d for mounting the second OIS drive unit 30Y at a diagonal portion located opposite the second base portion 21c. The OIS motor fixing part 21d is formed protruding from the first base portion 21b toward the light-receiving side in the optical axis direction and has a shape that can hold the second OIS drive unit 30Y.

[0073] Terminal metal parts 23 and wiring 24 are disposed on the base 21, for example, by insert molding. Wiring 24 includes power supply lines to the AF drive unit 14 and the OIS drive unit 30. Wiring 24 protrudes from the openings 21g formed at the four corners of the base 21 and is electrically connected to the OIS force application member 50. Power is supplied to the AF drive unit 14 and the first OIS drive unit 30X via the OIS force application member 50. Terminal metal parts 23 are electrically connected to wiring (not shown) formed on the sensor substrate 22.

[0074] Additionally, the base 21 has ball receiving portions 21e and 21f for accommodating the balls 41. The ball receiving portion 21e formed in the second base portion 21c is a circular recess, and the three ball receiving portions 21f formed in the first base portion 21b are rectangular recesses extending in the Y direction. The side surface of the ball receiving portion 21f is, for example, tapered in shape, with the groove width narrowing as it approaches the bottom surface.

[0075] The sensor substrate 22 has wiring (not shown) including power supply lines and signal lines for magnetic sensors 25X and 25Y. Magnetic sensors 25X and 25Y are mounted on the sensor substrate 22. Magnetic sensors 25X and 25Y are, for example, Hall elements or TMR (Tunnel Magnetoresistive) sensors, and are electrically connected to terminal metal members 23 via wiring (not shown) formed on the sensor substrate 22. Magnets 16X and 16Y are arranged on the first part 12 of the OIS movable part 10 at positions opposite to the magnetic sensors 25X and 25Y. The position of the OIS movable part 10 in the X and Y directions is detected by a position detection unit composed of magnetic sensors 25X and 25Y and magnets 16X and 16Y. Alternatively, the position of the OIS movable part 10 in the X and Y directions can be detected by a light sensor such as a light reflector, instead of magnets 16X and 16Y and magnetic sensors 25X and 25Y.

[0076] The OIS force-applying member 50, for example, is a helical tension spring that connects the OIS movable part 10 and the OIS fixed part 20. In this embodiment, one end of the OIS force-applying member 50 is connected to the wiring 24 of the base 21, and the other end is connected to the wiring 17 of the first stage 12. The OIS force-applying member 50 bears the tensile load when connecting the OIS movable part 10 and the OIS fixed part 20, and functions in a way that brings the OIS movable part 10 and the OIS fixed part 20 closer together. That is, the OIS movable part 10 is held in a state where it is pressed against the base 21 by the OIS force-applying member 50 along the optical axis, and is able to swing in the XY plane. Thus, the OIS movable part 10 can be held in a stable state without trembling.

[0077] In addition, in this embodiment, the OIS force-applying member 50 functions as a power supply line to the AF drive unit 14 and the first OIS drive unit 30X.

[0078] The OIS support 40 supports the OIS movable part 10 on the OIS fixed part 20 with the OIS movable part 10 spaced apart from the OIS fixed part 20 in the optical axis direction. In this embodiment, the OIS support 40 includes four balls 41 between the OIS movable part 10 (first platform 12 and second platform 13) and the base 21. One ball 41 disposed in the ball receiving portion 21e of the base 21 is located between the base 21 and the first platform 12, and three balls 41 disposed in the ball receiving portion 21f are located between the base 21 and the second platform 13.

[0079] Additionally, the OIS support 40, within the OIS movable part 10, includes three ball bearings 42 located between the first stage 12 and the second stage 13 (see reference). Figure 7 wait).

[0080] In this embodiment, by restricting the rotatable direction of the seven balls 41 and 42 constituting the OIS support 40, the OIS movable part 10 can swing with good precision in the XY plane. Furthermore, the number of balls 41 and 42 constituting the OIS support 40 can be appropriately varied.

[0081] The OIS drive unit 30 is an actuator that moves the OIS movable part 10 in the X and Y directions. Specifically, the OIS drive unit 30 includes: a first OIS drive unit 30X (first XY direction drive unit) that moves the OIS movable part 10 (AF unit only) in the X direction, and a second OIS drive unit 30Y (second XY direction drive unit) that moves the entire OIS movable part 10 in the Y direction.

[0082] The first OIS drive unit 30X and the second OIS drive unit 30Y are both ultrasonic motors. The first OIS drive unit 30X is fixed to the OIS motor fixing part 12f of the first unit 12, extending along the X direction. The second OIS drive unit 30Y is fixed to the OIS motor fixing part 21d of the base 21, extending along the Y direction. That is, the first OIS drive unit 30X and the second OIS drive unit 30Y are arranged along mutually orthogonal edges.

[0083] The structure of the OIS drive unit 30 is as follows: Figure 6A , Figure 6B As shown. Figure 6A This indicates the assembled state of the components of the OIS drive unit 30. Figure 6B This indicates the state after disassembling each component of the OIS drive unit 30. Furthermore, Figure 6A , Figure 6BThe second OIS driving section 30Y is shown, but the main structure of the first OIS driving section 30X, specifically, except for the shape of the OIS resonant section 31 and the electrode 33, is the same as that of the second OIS driving section 30Y. Therefore, Figure 6A , Figure 6B This is a diagram representing the OIS drive unit 30.

[0084] like Figure 6A , Figure 6B As shown, the OIS drive unit 30 includes an OIS resonant unit 31, an OIS piezoelectric element 32, and an OIS electrode 33. The driving force of the OIS drive unit 30 is transmitted to the second unit 13 via the OIS power transmission unit 34. Specifically, the first OIS drive unit 30X is connected to the first OIS power transmission unit 34X, and the second OIS drive unit 30Y is connected to the second OIS power transmission unit 34Y.

[0085] OIS piezoelectric element 32 is, for example, a plate-shaped element formed of ceramic material that generates vibration by applying a high-frequency voltage.

[0086] The OIS electrode 33 clamps the OIS resonant part 31 and the OIS piezoelectric element 32, and applies voltage to the OIS piezoelectric element 32. The OIS electrode 33 of the first OIS drive part 30X is electrically connected to the power supply board 18, and the OIS electrode 33 of the second OIS drive part 30Y is electrically connected to the wiring 24 of the base 21.

[0087] The OIS resonant section 31 is formed of a conductive material and resonates with the vibration of the OIS piezoelectric element 32, converting the vibrational motion into linear motion. In this embodiment, the OIS resonant section 31 has: a generally rectangular body 31a held by the OIS piezoelectric element 32; two arms 31b extending from the upper and lower parts of the body 31a; a protrusion 31c extending from the center of the body 31a along the Y direction; and an energized section 31d extending from the center of the body 31a to the side opposite to the protrusion 31c. The two arms 31b have a symmetrical shape, and their respective free ends abut against the OIS power transmission section 34, deforming symmetrically in resonance with the vibration of the OIS piezoelectric element 32. The energized section 31d of the first OIS drive section 30X is electrically connected to the wiring 17 of the first unit 12, and the energized section 31d of the second OIS drive section 30Y is electrically connected to the wiring 24 of the base 21.

[0088] The OIS piezoelectric element 32 is attached to the body 31a of the OIS resonant portion 31 in the thickness direction and is held by the OIS electrode 33, thereby electrically connecting them to each other. For example, one side of the power supply path is connected to the OIS electrode 33 and the other side is connected to the energized part 31d of the OIS resonant portion 31, thereby applying a voltage to the OIS piezoelectric element 32 and generating vibration.

[0089] The OIS resonant section 31 has at least two resonant frequencies, and deforms with different actions at each resonant frequency. In other words, the overall shape of the OIS resonant section 31 is set so that it deforms with different actions corresponding to the two resonant frequencies. The different actions refer to the actions of the OIS power transmission section 34 moving forward in the X or Y direction, and the actions of moving backward in the X or Y direction.

[0090] The OIS power transmission unit 34 is a clamping guide extending in one direction, with one end connected to the OIS drive unit 30 and the other end connected to the second platform 13. The OIS power transmission unit 34 includes an OIS motor abutment part 34a, a platform fixing part 34c, and a connecting part 34b. The OIS motor abutment part 34a is formed with a generally U-shaped cross-section and abuts against the free end of the arm 31b of the OIS resonance unit 31. The platform fixing part 34c is disposed at the end of the OIS power transmission unit 34 and is fixed to the OIS clamping guide fixing part 13c of the second platform 13 (see reference). Figure 8 (etc.). The connecting part 34b is the part that connects the OIS motor abutment part 34a and the platform fixing part 34c. It branches into two parts from the platform fixing part 34c and the two parts are formed to be parallel to each other.

[0091] The width between the OIS motor abutment portions 34a is set to be wider than the width between the free ends of the arms 31b of the OIS resonance portion 31. Therefore, when the OIS power transmission portion 34 is installed on the OIS drive portion 30, the OIS power transmission portion 34 functions as a leaf spring, causing the pushing force to act in the direction that expands the arms 31b of the OIS resonance portion 31. Through this pushing force, the OIS power transmission portion 34 is held between the free ends of the arms 31b of the OIS resonance portion 31, and the driving force from the OIS resonance portion 31 is efficiently transmitted to the OIS power transmission portion 34.

[0092] The OIS drive unit 30 and the OIS power transmission unit 34 only come into contact under pressure. Therefore, there is no need to increase the size of the lens drive device 1. By simply increasing the contact portion in the X or Y direction, the travel distance (stroke) of the OIS movable part 10 can be increased.

[0093] The first OIS drive unit 30X is fixed to the OIS movable part 10 (first platform 12) and connected to the second platform 13 via the OIS power transmission unit 34X. When the second OIS drive unit 30Y performs jitter correction in the Y direction, it moves together with the OIS movable part 10. On the other hand, the second OIS drive unit 30Y is fixed to the OIS fixed part 20 (base 21) and connected to the second platform 13 via the OIS power transmission unit 34Y. This second OIS drive unit 30Y is not affected by the jitter correction in the X direction performed by the first OIS drive unit 30X. That is, the 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 swing with good accuracy in the XY plane.

[0094] Figures 7-9 This is an exploded perspective view of the OIS movable part 10. Figure 8 Showing Figure 7 The state after rotating 180° around the Z-axis. Figure 9 It means to make Figure 7 The bottom 3D view shows the state after rotating 90° around the Z-axis.

[0095] like Figures 7-9 As shown, in this embodiment, the OIS movable part 10 includes an AF movable part 11, a first stage 12, a second stage 13, an AF drive part 14, and an AF support part 15. Regarding movement in the Y direction, the entire OIS movable part 10, including the first stage 12 and the second stage 13, is a movable body. In contrast, regarding movement in the X direction, the second stage 13 functions as an OIS fixed part 20, and only the AF unit functions as an OIS movable part 10. Furthermore, the first stage 12 functions as an AF fixed part.

[0096] The AF movable part 11 is the part that moves in the direction of the optical axis during focusing. The AF movable part 11 is arranged radially spaced from the first stage part 12 (AF fixed part) and is connected to the first stage part 12 via the AF support part 15.

[0097] The movable part 11 of AF has a lens holding part 2 (see reference). Figure 2 The lens holder 111 and the force-applying component 112 for AF.

[0098] The lens holder 111 is formed, for example, of polyarylate (PAR), a PAR alloy composed of a mixture of various resin materials including PAR, or a liquid crystal polymer. The lens holder 111 has a cylindrical lens receiving portion 111a. Lens portion 2 (see reference) Figure 2 For example, it is fixed to the lens receiving part 111a by adhesive.

[0099] The lens holder 111 has an upper flange 111b on the upper outer periphery of the lens receiving portion 111a and a lower flange 111c on the lower outer periphery. In this embodiment, four upper flanges 111b are provided at positions corresponding to the four corners of the lens driving device 1, and a lower flange 111c is provided below two opposing upper flanges 111b. The upper flanges 111b function as limiting portions restricting the movement of the lens holder 111 toward the imaging side (lower side) in the optical axis direction, and the lower flanges 111c function as limiting portions restricting the movement of the lens holder 111 toward the light-receiving side (upper side) in the optical axis direction.

[0100] Additionally, the lens holder 111 has a ball bearing receiving portion 111d on the circumferential surface of the lens receiving portion 111a to accommodate the AF support portion 15. In this embodiment, the ball bearing receiving portion 111d is provided at two locations symmetrical about a diagonal direction (the midway between the X and Y directions) and opens on the same side (opposite to the side where the AF force-applying member 112 is located) with respect to the other diagonal direction.

[0101] The AF force-applying component 112 is formed of a metal material such as titanium copper, nickel copper, or stainless steel, and is arranged to extend circumferentially in the lens holder 111. In this embodiment, the AF force-applying component 112 is formed, for example, by bending a metal sheet, and has a leaf spring portion 112a extending in mutually orthogonal directions and a connecting portion 112b connecting the leaf spring portion 112a. The leaf spring portion 112a has a shape symmetrical about the connecting portion 112b, and the end portion 112c of the leaf spring portion 112a is formed to be folded back into a generally U-shape (hereinafter referred to as "AF motor abutment portion 112c").

[0102] The AF force-applying member 112 is fixed to the lens holder 111 by installing a connecting part 112b on one side of the space between the upper flange 111b and the lower flange 111c of the lens holder 111. The leaf spring part 112a extends along the X and Y directions.

[0103] The first stage 12 is the part that supports the movable AF part 11 across the AF support part 15. On the imaging side of the first stage 12 in the optical axis direction, a second stage 13 is disposed across the ball bearing 42. The first stage 12 moves in both the X and Y directions during jitter correction, while the second stage 13 moves only in the X direction during jitter correction.

[0104] The first portion 12 is a generally rectangular cylindrical component, for example, formed of a liquid crystal polymer. The first portion 12 has a generally circular opening 12a in the portion corresponding to the lens holder 111. In the first portion 12, the two sidewalls corresponding to the second portion 13 are formed to be thinner than the other sidewalls by an amount less than the thickness of the second portion.

[0105] The first stage 12 has three ball receiving portions 12b for receiving balls 42 and a ball receiving portion 12c for receiving balls 41 on its lower surface. The ball receiving portions 12b are formed as elongated oval recesses extending in the X direction. In addition, the side of the ball receiving portion 12b is formed as a tapered shape, with the groove width narrowing as it approaches the bottom surface. The ball receiving portion 12c is formed as a circular recess. The ball receiving portions 12b and the ball receiving portion 13a of the second stage 13 are opposite each other in the Z direction, and the ball receiving portion 12c and the ball receiving portion 21e of the base 21 are opposite each other in the Z direction.

[0106] The first part 12 has inwardly protruding flanges 12d at its four lower corners. When the lens holder 111 is mounted on the first part 12, the upper flange 111b of the lens holder 111 is located above the flanges 12d, and the lower flange 111c of the lens holder 111 is located below the two diagonally opposite flanges 12d. That is, both flanges 12d are clamped by the upper flange 111b and the lower flange 111c of the lens holder 111 at a movable distance spaced apart from the lens holder 111.

[0107] The first unit 12 has a ball bearing fixing part 12e for fixing the AF support part 15 on the inner surface of one of the side walls along the X direction and the inner surface of one of the side walls along the Y direction. The first unit 12 has an OIS motor fixing part 12f for fixing the first OIS drive part 30X on the outer surface of the side wall along the X direction. In the first unit 12, the side wall along the Y direction is formed with the outer side facing inward, and when the lens drive device 1 is assembled, the second OIS drive part 30Y is located on the outer surface of the side wall along the Y direction.

[0108] Furthermore, in the first unit 12, AF drive units 14A and 14B are arranged on the inner surfaces of the sidewalls on the opposite side along the X direction and on the inner surfaces of the sidewalls on the opposite side along the Y direction. On the lower surfaces of these sidewalls, magnets 16X and 16Y for detecting XY positions are arranged opposite to the magnetic sensors 25X and 25Y in the Z direction. For example, magnet 16X is magnetized in the X direction, and magnet 16Y is magnetized in the Y direction.

[0109] In the first unit 12, wiring 17 is embedded, for example, by insert molding. Wiring 17 protrudes from notches on the outer surface of the four corners of the first unit 12, where one end of the OIS force-applying member 50 is connected. Furthermore, a power supply board 18, electrically connected to wiring 17, is disposed on the upper surface of the first unit 12. Power is supplied to the AF drive unit 14 and the first OIS drive unit 30X via wiring 17 and power supply board 18.

[0110] The second unit 13 is an L-shaped component, for example, formed of a liquid crystal polymer. The inner peripheral surface of the second unit 13 is formed in an arc shape along the outline of the lens holder 111. The outer surface of the sidewall of the second unit 13 along the Y direction is formed to be recessed inward, similar to the first unit 12. When the lens driving device 1 is assembled, the second OIS driving part 30Y is located on the outer surface of the sidewall of the second unit 13 along the Y direction. In this embodiment, by forming the second unit 13 into an L-shape and placing the second unit 13 below the two sidewalls of the first unit 12 which are formed to be thinner, the height of the OIS movable part 10 is reduced.

[0111] The second part 13 has three ball receiving portions 13a on its lower surface for receiving balls 41. The ball receiving portions 13a are opposite to the ball receiving portions 21f of the base 21. The ball receiving portions 13a are formed as elongated oval recesses extending in the Y direction. In addition, the side of the ball receiving portion 13a is formed in a tapered shape such that the groove width narrows as it approaches the bottom surface.

[0112] Furthermore, the second stage 13 has three ball receiving portions 13b on its upper surface for accommodating balls 42. The ball receiving portions 13b are opposite to the ball receiving portions 12b of the first stage 12 in the Z direction. The ball receiving portions 13b are formed as elongated oval recesses extending in the X direction. The side surfaces of the ball receiving portions 12b are tapered in shape, with the groove width narrowing as they approach the bottom surface.

[0113] The three balls 41 constituting the OIS support 40 are held in a multi-point contact manner by the ball receiving portion 21f of the base 21 and the ball receiving portion 13a of the second stage 13. Therefore, the balls 41 rotate stably in the X direction.

[0114] Furthermore, the ball 42 is held in a multi-point contact manner by the ball receiving portion 13b of the second unit 13 and the ball receiving portion 12b of the first unit 12. Therefore, the ball 42 rotates stably in the X direction.

[0115] The AF support 15 is composed of balls. In this embodiment, three balls are arranged in the Z direction. The AF support 15 is rotatably positioned between the ball receiving portion 111d of the lens holder 111 and the ball fixing portion 12e of the first stage 12.

[0116] The AF drive unit 14 is an actuator that moves the AF movable part 11 in the Z direction. The AF drive unit 14 is composed of a first AF drive unit 14A (first Z direction drive unit) and a second AF drive unit 14B (second Z direction drive unit). Like the OIS drive unit 30, the AF drive unit 14 is composed of an ultrasonic motor. The first AF drive unit 14A and the second AF drive unit 14B are fixed to the inner peripheral surface of the first stage 12 along the X and Y directions, respectively.

[0117] The structure of the AF drive unit 14 is as follows Figure 10A , Figure 10B As shown. Figure 10A The diagram shows the assembled state of the components of the AF drive unit 14. Figure 10B The diagram shows the disassembled state of the AF drive unit 14. Furthermore, Figure 10A , Figure 10B The second AF drive unit 14B is shown, but the main structure of the first AF drive unit 14A, specifically, except for the shape of the AF electrode 143, is the same as that of the second AF drive unit 14B. Therefore, Figure 10A , Figure 10B This diagram represents the AF drive unit 14. The structure of the AF drive unit 14 is almost identical to that of the OIS drive unit 30.

[0118] like Figure 10A , Figure 10B As shown, the AF drive unit 14 includes an AF resonant unit 141, an AF piezoelectric element 142, and an AF electrode 143. The driving force of the AF drive unit 14 is transmitted to the lens holder 111 via the AF force application member 112.

[0119] The AF piezoelectric element 142 is, for example, a plate-shaped element made of ceramic material, which generates vibration by applying a high-frequency voltage. Two AF piezoelectric elements 142 are arranged such that the body 141a of the AF resonant part 141 is sandwiched in the middle.

[0120] The AF electrode 143 clamps the AF resonant part 141 and the AF piezoelectric element 142, and applies a voltage to the AF piezoelectric element 142.

[0121] The AF resonant section 141 is formed of a conductive material and resonates with the vibration of the AF piezoelectric element 142, converting the vibrational motion into linear motion. In this embodiment, the AF resonant section 141 has: a generally rectangular body 141a held by the AF piezoelectric element 142; two arms 141b extending from the upper and lower parts of the body 141a along the X or Y direction; a protrusion 141c extending from the center of the body 141a along the X or Y direction; and a current-carrying section 141d extending from the center of the body 141a to the side opposite to the protrusion 141c and electrically connected to the power supply path (wiring 17 of the first unit 12). The two arms 141b have a symmetrical shape except for their free ends and deform symmetrically with the vibration of the AF piezoelectric element 142. The free ends of the two arms 141b have different shapes from each other, such that only one free end abuts against the AF force-applying member 112. Furthermore, as long as the shape of the force-applying member 112 for AF can be adjusted so that only one free end abuts against the force-applying member 112 for AF, the free ends of the two arms 141b can also have symmetrical shapes.

[0122] The AF piezoelectric element 142 is attached to the body 141a of the AF resonant portion 141 in the thickness direction and is held by the AF electrode 143, thereby electrically connecting them to each other. The power supply board 18 is connected to the AF electrode 143, and the wiring 17 of the first unit 12 is connected to the energized portion 141d of the AF resonant portion 141, thereby applying voltage to the AF piezoelectric element 142 and generating vibration.

[0123] Like the OIS resonant part 31, the AF resonant part 141 has at least two resonant frequencies and deforms with different actions at each resonant frequency. In other words, the overall shape of the AF resonant part 141 is set so that it deforms with different actions corresponding to the two resonant frequencies.

[0124] The first AF drive unit 14A and the second AF drive unit 14B are fixed to the inner peripheral surfaces of the first stage 12 along the X and Y directions, respectively. In this embodiment, the front end of one of the two arms 141b (e.g., the lower arm 141b) in the first AF drive unit 14A and the second AF drive unit 14B abuts against the AF force application member 112, thereby causing the AF movable part 11 to move in the Z direction. The arm 141b that abuts against the AF force application member 112 is referred to as the "first arm 141b", and the arm 141b that does not abut against the AF force application member 112 is referred to as the "second arm 141b". Furthermore, if the front ends of both the upper and lower arms 141b of the AF resonance part 141 abut against the AF force application member 112, the two arms 141b will slide due to their symmetrical movement, preventing the AF movable part 11 from moving in the Z direction.

[0125] In this embodiment, the AF drive unit 14 moves in the Z direction by only abutting the first arm 141b against the AF movable part 11 (AF force application member 112). Therefore, compared with the case where the OIS drive unit 30 uses two arms 31b to transmit the driving force, the transmitted driving force is halved. Therefore, by providing two AF drive units 14, the driving force for movement in the optical axis direction is ensured.

[0126] When assembling the AF unit and bringing the AF drive unit 14 into contact with the AF force-applying member 112, the AF force-applying member 112 functions as a leaf spring, and the AF movable part 11 (lens bracket 111) is subjected to force on the first stage part 12 (AF fixing part) via the AF support part 15 (see reference). Figure 11A , Figure 11B ).

[0127] Specifically, the first arm 141b of the first AF drive unit 14A and the second AF drive unit 14B abuts against both ends of the AF force application member 112, thereby applying force to the lens holder 111 relative to the first platform (AF fixing part) in one direction within the orthogonal plane of the optical axis. In this embodiment, the lens holder 111 is pressed by the AF force application member 112, thereby applying force relative to the first platform (AF fixing part) in a direction midway between the X and Y directions.

[0128] Through this force application, the AF force application component 112 is pressed against the front end of the arm 141b of the AF resonance section 141, and the driving force from the AF resonance section 141 is efficiently transmitted to the AF force application component 112. In addition, the AF force application component 112 also has the following functions: transmitting the driving force of the AF drive section 14 and applying force to the AF movable section 11 towards the first stage section 12, thus simplifying the component structure.

[0129] Furthermore, the AF support 15 is provided at two locations corresponding to the first AF drive 14A and the second AF drive 14B. The AF movable part 11 is subjected to force on the first platform 12 through the AF support 15 provided at the two locations, so the AF movable part 11 is held in a stable posture.

[0130] The AF drive unit 14 and the AF force application member 112 only come into contact under pressure. Therefore, by increasing the contact portion in the Z direction, the travel distance (stroke) of the AF movable part 11 can be easily increased without hindering the reduction of the lens drive device 1. However, the travel distance of the AF movable part 11 is limited to the extent that the AF force application member 112 does not come into contact with another arm 141b of the AF resonance unit 141 (e.g., the upper arm 141b) that does not interfere with the movement of the AF movable part 11.

[0131] Furthermore, the first arm 141b of the AF resonance section 141 abuts against the AF force-applying member 112, which is a metal molded part. As a result, compared to the case where the first arm 141b abuts against the lens holder 111, which is a resin molded part, the driving force of the AF drive section 14 can be transmitted more efficiently.

[0132] In the lens driving device 1, when a voltage is applied to the AF driving unit 14, the AF piezoelectric element 142 vibrates, and the AF resonant part 141 deforms in a manner corresponding to the frequency. At this time, the voltage is applied in such a way that the first AF driving unit 14A and the second AF driving unit 14B exhibit the same operation. Through the driving force of the AF driving unit 14, the AF sliding member 112 slides in the Z direction. Accompanying this, the AF movable part 11 moves in the Z direction, thereby achieving focusing. The AF support part 15 is composed of ball bearings, so the AF movable part 11 can move smoothly in the Z direction.

[0133] 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 resonant part 31 deforms in accordance with the frequency. Driven by the OIS driving unit 30, the OIS power transmission part 34 slides in the X or Y direction. Simultaneously, the OIS movable part 10 moves in the X or Y direction, thereby correcting for jitter. The OIS support part 40 is composed of ball bearings, thus enabling the OIS movable part 10 to move smoothly in the X or Y direction.

[0134] Specifically, when the first OIS drive unit 30X is driven and the OIS power transmission unit 34 moves in the X direction, power is transmitted from the first stage 12, where the first OIS drive unit 30X is located, to the second stage 13. At this time, the ball bearings 41 (three balls housed in the ball bearing housing 21f) held by the second stage 13 and the base 21 cannot rotate in the X direction, so the position of the second stage 13 relative to the base 21 in the X direction remains unchanged. On the other hand, the ball bearings 42 held by the first stage 12 and the second stage 13 can rotate in the X direction, so the first stage 12 moves relative to the second stage 13 in the X direction. In other words, the second stage 13 constitutes the OIS fixed part 20, and the first stage 12 constitutes the OIS movable part 10.

[0135] Furthermore, when the second OIS drive unit 30Y is driven and the OIS power transmission unit 34 moves in the Y direction, power is transmitted from the base 21, on which the second OIS drive unit 30Y is located, to the second stage 13. At this time, the ball 42 held by the first stage 12 and the second stage 13 cannot rotate in the Y direction, so the position of the first stage 12 relative to the second stage in the Y direction remains unchanged. On the other hand, the ball 41 (the three balls housed in the ball receiving portion 21f) held by the second stage 13 and the base 21 can rotate in the Y direction, so the second stage 13 moves relative to the base 21 in the Y direction. 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 part 20, and the AF unit including the first stage 12 and the second stage 13 constitutes the OIS movable part 10.

[0136] In this way, the OIS movable part 10 swings in the XY plane, thereby correcting for jitter. Specifically, based on the detection signal representing angular jitter from the jitter detection unit (e.g., a gyroscope sensor, not shown), the energizing voltage of the OIS drive units 30X and 30Y is controlled to cancel out the angular jitter of the camera module A. At this time, by feeding back the detection results of the XY position detection unit composed of magnets 16X and 16Y and magnetic sensors 25X and 25Y, the translational movement of the OIS movable part 10 can be accurately controlled.

[0137] As described above, the lens driving device 1 of the embodiment includes: a first base 12 (first fixed part); an AF movable part 11 (first movable part) spaced apart from the first base 12; an AF support part 15 (first support part) supporting the AF movable part 11 relative to the first base 12; and an AF driving part 14 (Z-direction driving part) disposed on the first base 12, which moves the AF movable part 11 relative to the first base 12 in the optical axis direction. The AF driving part 14 is composed of an ultrasonic motor having an AF piezoelectric element 142 and an AF resonant part 141 that converts vibrational motion into linear motion. The AF resonant part 141 has a torso 141a held by the AF piezoelectric element 142, and a first arm and a second arm 141b extending from the torso 141a in the same direction. The first arm and the second arm 141b deform due to vibrational resonance with the AF piezoelectric element, and only the first arm 141b abuts against the AF movable part 11.

[0138] According to the lens drive device 1, the AF drive unit 14 is composed of an ultrasonic motor, which reduces the influence of external magnetism and enables miniaturization and low height. Therefore, even if the camera module A with the lens drive device 1 is placed close together, as in a smartphone M, there will be no magnetic influence, making it extremely suitable for use in dual-lens cameras.

[0139] Furthermore, in the lens drive device 1, the AF movable part 11 is subjected to force on the first stage (AF fixed part) via the AF support part 15. As a result, the driving force of the AF drive part 14 can be efficiently transmitted to the AF movable part 11.

[0140] [Second Implementation]

[0141] Figure 12A , Figure 12B This is a perspective view of the lens driving device 1A according to the second embodiment. Figure 12B Showing will Figure 12A The state after rotating 180° around the Z-axis. Except for the structure of the OIS movable part 10A, the lens driving device 1A of the second embodiment is almost the same as the lens driving device 1 of the first embodiment. For the same or corresponding components as the lens driving device 1 of the first embodiment, the same reference numerals are used and the description is omitted. Here, the OIS movable part 10A (especially the AF movable part 51) will be described.

[0142] Figures 13-15 This is an exploded perspective view of the OIS movable part 10. Figure 14 Showing Figure 13 The state after rotating 180° around the Z-axis. Figure 15 It means to make Figure 13 The bottom 3D view shows the state after rotating 90° around the Z-axis.

[0143] like Figures 13-15 As shown, in the second embodiment, the OIS movable part 10A includes: an AF movable part 51, a first stage 12, a second stage 13, an AF drive part 14, and an AF support part 15. Regarding movement in the Y direction, the OIS movable part 10A, including the first stage 12 and the second stage 13, is a movable body as a whole. In contrast, regarding movement in the X direction, the second stage 13 functions as an OIS fixed part 20, and only the AF unit functions as an OIS movable part 10. Furthermore, the first stage 12 functions as an AF fixed part.

[0144] The AF movable part 51 is the part that moves in the direction of the optical axis during focusing. The AF movable part 51 is arranged radially spaced from the first stage part 12 (AF fixed part) and is connected to the first stage part 12 via the AF support part 15.

[0145] The movable part 51 of AF has a lens holding part 2 (see reference). Figure 2 The lens holder 511 and the force-applying component 512 for AF.

[0146] The lens holder 511 is formed, for example, of polyarylate (PAR), a PAR alloy composed of a mixture of various resin materials including PAR, or a liquid crystal polymer. The lens holder 511 has a cylindrical lens receiving portion 511a. Lens portion 2 (see reference) Figure 2 For example, it is fixed to the lens receiving part 511a by adhesive.

[0147] The lens holder 511 has an upper flange 511b on the upper outer periphery of the lens receiving portion 511a. In the second embodiment, four upper flanges 511b are provided at positions corresponding to the four corners of the lens driving device 1A. The upper flanges 511b function as limiting portions that restrict the movement of the lens holder 511 toward the imaging side (lower side) in the optical axis direction.

[0148] A magnet receiving portion 511c is provided on one of the four upper flange portions 511b, which houses a magnet 16Z for detecting the Z position. The magnet 16Z is disposed in the magnet receiving portion 511c, on the sensor substrate 22 (see reference). Figure 4 A magnetic sensor (e.g., Hall element, TMR sensor, etc.) for detecting the Z position is arranged at a position opposite to the magnet 16Z in the optical axis direction (illustration omitted). Alternatively, instead of the magnet 16Z and the magnetic sensor (illustration omitted), the position of the AF movable part 51 in the Z direction can be detected by an optical sensor such as a light reflector.

[0149] Additionally, the lens holder 511 has a ball bearing receiving portion 511d on the circumferential surface of the lens receiving portion 511a to accommodate the AF support portion 15. In the second embodiment, the ball bearing receiving portion 511d is provided at two locations symmetrical about a diagonal direction (the midway between the X and Y directions) and opens on the same side (the side where the AF force-applying member 512 is disposed) relative to the other diagonal direction.

[0150] The AF force-applying component 512 is made of metal materials such as titanium copper, nickel copper, or stainless steel. The AF force-applying component 512 is, for example, constructed from a flat, dumbbell-shaped leaf spring. The AF drive units 14A and 14B abut against the two ends 512a of the AF force-applying component 512 along its length. Furthermore, the spring constant of the AF force-applying component 512 is adjusted by reducing its weight.

[0151] The AF force-applying member 512 is disposed in the space 511e formed between the magnet receiving portion 511c and the lens receiving portion 511a, and is held by the spacer 513 and the magnet receiving portion 511c. The AF force-applying member 512 extends in contact with the lens receiving portion 511a.

[0152] The first AF drive unit 14A and the second AF drive unit 14B are fixed to the inner peripheral surfaces of the first stage 12 along the X and Y directions, respectively. In the second embodiment, the front end of one of the two arms 141b (e.g., the upper arm 141b) in the first AF drive unit 14A and the second AF drive unit 14B abuts against the AF force application member 512, thereby causing the AF movable part 51 to move in the Z direction. The arm 141b that abuts against the AF force application member 512 is referred to as the "first arm 141b", and the arm 141b that does not abut against the AF force application member 512 is referred to as the "second arm 141b". Furthermore, if the front ends of both the upper and lower arms 141b of the AF resonance part 141 abut against the AF force application member 112, the two arms 141b will slide due to their symmetrical movement, preventing the AF movable part 11 from moving in the Z direction.

[0153] In the second embodiment, the AF drive unit 14 moves in the Z direction by only abutting the first arm 141b against the AF movable part 11 (AF force-applying member 112). Therefore, compared with the case where the OIS drive unit 30 uses two arms 31b to transmit the driving force, the transmitted driving force is halved. Therefore, by providing two AF drive units 14, the driving force for movement in the optical axis direction is ensured.

[0154] When assembling the AF unit and bringing the AF drive unit 14 into contact with the AF force-applying member 512, the AF force-applying member 512 functions as a leaf spring, and the AF movable part 51 is subjected to force on the first unit 12 (AF fixing part) via the AF support part 15 (see reference). Figure 16A , Figure 16B ).

[0155] Specifically, the first arm 141b of the first AF drive unit 14A and the second AF drive unit 14B abuts against both ends of the AF force application member 512, thereby applying force to the lens holder 111 relative to the first platform (AF fixing part) in one direction within the orthogonal plane of the optical axis. In the second embodiment, the lens holder 111 is pulled by the AF force application member 512, thereby applying force relative to the first platform (AF fixing part) in a direction intermediate between the X and Y directions.

[0156] Through this force application, the AF force application component 512 is pressed against the front end of the arm 141b of the AF resonance section 141, and the driving force from the AF resonance section 141 is efficiently transmitted to the AF force application component 512. In addition, the AF force application component 512 also has the following functions: transmitting the driving force of the AF drive section 14 and applying force to the AF movable section 51 towards the first stage section 12, thus simplifying the component structure.

[0157] Furthermore, in the second embodiment, the force-applying member 512 for the AF is made of a flat, dumbbell-shaped leaf spring, which exerts a large pushing force. Therefore, the sinking caused by the weight of the movable part 51 of the AF is suppressed, and the posture of the movable part 51 of the AF relative to the first platform 12 is stabilized. Thus, the driving force of the AF drive unit 14 can be efficiently transmitted to the movable part 51 of the AF, and the responsiveness is improved.

[0158] Furthermore, the AF support 15 is provided at two locations corresponding to the first AF drive 14A and the second AF drive 14B. The AF movable part 11 is subjected to force on the first platform 12 through the AF support 15 provided at the two locations, so the AF movable part 51 is held in a stable posture.

[0159] The AF drive unit 14 and the AF force application member 512 only come into contact under pressure. Therefore, by increasing the contact portion in the Z direction, the travel distance (stroke) of the AF movable part 51 can be easily increased without hindering the reduction of the lens drive device 1A. However, the travel distance of the AF movable part 51 is limited to the extent that the AF force application member 512 does not come into contact with another arm 141b of the AF resonance unit 141 (for example, the lower arm 141b) that does not interfere with the movement of the AF movable part 51.

[0160] Furthermore, the first arm 141b of the AF resonance section 141 abuts against the AF force-applying member 512, which is a metal molded part. As a result, compared to the case where the first arm 141b abuts against the lens holder 111, which is a resin molded part, the driving force of the AF drive section 14 can be transmitted more efficiently.

[0161] As described above, the lens driving device 1A of the second embodiment includes: a first base 12 (first fixed part); an AF movable part 51 (first movable part) disposed spaced apart from the first base 12; an AF support part 15 (first support part) supporting the AF movable part 51 relative to the first base 12; and an AF driving part 14 (Z-direction driving part) disposed on the first base 12, which moves the AF movable part 51 relative to the first base 12 in the optical axis direction. The AF driving part 14 is composed of an ultrasonic motor having an AF piezoelectric element 142 and an AF resonant part 141 that converts vibrational motion into linear motion. The AF resonant part 141 has a torso 141a held by the AF piezoelectric element 142, and a first arm and a second arm 141b extending from the torso 141a in the same direction. The first arm and the second arm 141b deform due to the vibration resonance with the AF piezoelectric element 142, and only the first arm 141b abuts against the movable part 51 of AF (the force-applying member 512 of AF).

[0162] According to the lens drive device 1A, the AF drive unit 14 is composed of an ultrasonic motor, which reduces the influence of external magnetism and enables miniaturization and low height. Therefore, even if the camera module A with the lens drive device 1 is placed close together, as in a smartphone M, there will be no magnetic influence, making it extremely suitable for dual-lens cameras.

[0163] Furthermore, in the lens driving device 1A, the AF movable part 51 is subjected to force on the first part (AF fixed part) via the AF support part 15. As a result, the driving force of the AF driving part 14 can be efficiently transmitted to the AF movable part 51.

[0164] [Control method of the drive unit]

[0165] In the lens driving device 1 of the first embodiment and the lens driving device 1A of the second embodiment, the AF driving unit 14 and the OIS driving unit 30 (driving unit) are controlled, for example, as follows. In the driving unit shown below, the "active element C-1" corresponds to the AF resonance unit 141 and the OIS resonance unit 31, and the "passive element C-4" corresponds to the AF force application members 112 and 512 and the OIS power transmission unit 34.

[0166] In principle, the same reference numerals are assigned to the same or functionally identical parts in these figures. Figure 17A drive unit with active element C-1 is shown. Active element C-1 includes a resonator C-2 (corresponding to AF resonator 141 and OIS resonator 31), which has a pair of arms: a first arm C-21 and a second arm C-22. Arms C-21 and C-22, and mounting portion C-14, are connected to a connecting portion C-20 of the resonator C-2. The resonator C-2 is mounted to a base element and other parts via the mounting portion C-14.

[0167] An excitation unit C-23, such as a piezoelectric element, is disposed on the connecting part C-20 (corresponding to AF piezoelectric element 142 and OIS piezoelectric element 32). A controller C-90 is disposed to generate an excitation signal or excitation voltage for driving the excitation unit C-23. A sensor C-91 is disposed to measure the position and / or velocity of the passive element C-4 relative to the active element C-1. The sensor C-91 measures the position and / or velocity of the passive element C-4 based on the magnetic field affected by the position of the passive element C-4. A Hall sensor can be used as the sensor C-91.

[0168] Excitation element C-23 comprises two separate elements disposed on either side of excitation element C-23. Resonator C-2 and excitation element C-23 are flat elements, stacked on top of each other and extending parallel to the reference plane C-28 (see reference). Figure 19 ).

[0169] If excited by an AC voltage at an excitation frequency, arms C-21 and C-22 vibrate, and the first contact portion C-31 of the first arm C-21 performs a generally linear motion corresponding to the frequency. This linear vibration can have orthogonal components, and the overall motion can be considered a perfect circle. The direction of the linear vibration (forward and backward) changes according to the frequency. The first contact portion C-31 repeatedly contacts the first contact area C-41 of the passive element C-4, driving the first contact area C-41 relative to the active element C-1. The same applies to the second contact portion C-32 and the second contact area C-42.

[0170] Corresponding to the direction of the linear forward and backward movement, the passive element C-4 is repeatedly pressed in the corresponding direction, and corresponding to how the passive element C-4 is suspended, for example, linear and / or rotational movements are performed. Figure 17 In the embodiment shown, the passive element C-4 rotates relative to the active element C-1.

[0171] Based on the specific geometry of these parts and the configuration in which the passive element C-4 moves relative to the active element C-1, for the desired (rotational or linear) direction of motion, the excitation frequency that brings the maximum energy transfer to the desired motion can be determined for each vibration or pulse and the resulting pressing motion. To reduce the energy transfer of each pulse, the excitation frequency can be slightly varied so that the vibration motion changes slightly but the general direction remains the same. As a result, the contact angle between the first contact part C-31 and the second contact part C-32 and the contact areas C-41, C-42, as well as the amplitude of their vibration, changes, resulting in a reduction in the energy transferred per pulse compared to the optimal angle. Thus, the moving speed of the passive element C-4 can be controlled by utilizing a slight relative change in the excitation frequency.

[0172] Prestress is applied between the first contact portion C-31 and the first contact area C-41, and between the second contact portion C-32 and the second contact area C-42. The prestress is generated by the elasticity of the first arm C-21 and the second arm C-22. If the passive element C-4 is positioned between the first contact portion C-31 and the second contact portion C-32, then the first arm C-21 and the second arm C-22 are pressed in a direction that separates them from each other.

[0173] The first arm C-21 and the second arm C-22 extend substantially symmetrically from the connecting portion C-20, but when manufactured from a flat sheet of material, their shapes, especially the subtle details of their contours, may sometimes differ. The resonator axis C-24 corresponds to an axis of symmetry that mirrors the resonator C-2, especially the connecting portion C-20, and the first and second arms C-21, except for the aforementioned subtle details of the arms. When excited by the excitation unit C-23, the movement of the connecting portion C-20 and the arms C-21 and C-22 is approximately symmetrical about the same axis of symmetry. The node of this movement, i.e., the region of minimum movement, is located on the resonator axis C-24. The mounting portion C-14 for mounting the active element C-1 to other elements is also located on the resonator axis C-24.

[0174] Figure 18A , Figure 18B The deformed form of active element C-1 is shown, while passive element C-4 has been omitted for ease of observation. Figure 18A Show Figure 17 The active element C-1 is shown. In Figure 18B As shown by the double-headed arrow corresponding to the resonator axis C-24, the active element C-1 is positioned such that, particularly within the plane containing the two arms C-21 and C-22, the passive element is driven in a straight line. Figure 18A , Figure 18BIn the middle, the excitation unit C-23 is installed on both sides of the resonator C-2.

[0175] Figure 19 It shows that it has the nature of being similar to Figure 17 The drive unit shown is a drive unit with the same elements as the drive unit shown. This drive unit also has a pair of arms C-21, C-22, but only the first arm C-21 contacts and drives the passive element C-4. As shown by the linear motion axis C-26, the motion of the drive unit is linear.

[0176] In the above embodiment, the passive element C-4 is disposed between arms C-21 and C-22, with the contact portions C-31 and C-32 at the ends of the arms facing inwards towards each other. In other embodiments, although not shown in the figures, arms C-21 and C-22 have an outward shape with the contact portions C-31 and C-32 facing in a direction separating them from each other. The passive element C-4 is disposed such that it contacts one or both of the contact portions C-31 and C-32 from the outside.

[0177] Further embodiments of the drive unit capable of applying the drive methods described in this specification are disclosed in International Publication No. 2006 / 000118, U.S. Patent No. 7,429,812, and International Publication No. 2019 / 068708, which are incorporated herein by reference in their entirety.

[0178] Figure 20 Along the same time axis t, the amplitudes A1, A2, and A3 of the vibrations of the three driving signals D1, D2, and D3, and the corresponding active element C-1, are shown.

[0179] The first driving signal D1 is a rectangular signal with a period of Te, also known as the "pulse period," and the excitation frequency fe is represented by fe = 1 / Te. The maximum pulse width of the first driving signal D1 is Te / 2, that is, the pulse duty cycle dp is 50%.

[0180] Assuming the pulse sequence of the first driving signal D1 begins at start time t0, the first amplitude A1 of the corresponding vibration increases as subsequent pulses from the excitation unit C-23 transfer mechanical energy to the active element C-1, and especially as mechanical energy is transferred to the resonator C-2 and its arms C-21 and C-22. After several pulses, the vibration reaches its maximum, and then essentially becomes constant in a steady state.

[0181] When the first amplitude A1 is below the activation threshold At, arms C-21 and C-22 do not apply a driving force to the passive element C-4. When the first amplitude A1 is above the activation threshold At, arms C-21 and C-22 apply a driving force to the passive element C-4, and the passive element C-4 is driven relative to the active element C-1. The same applies to the second amplitude A2 and the third amplitude A3.

[0182] The second driving signal D2 is obtained by amplitude modulation of the first driving signal D1, with the amplitude reduced relative to the maximum value (amplitude of the first driving signal D1). The third driving signal D3 is obtained by pulse width modulation of the first driving signal D1, with the pulse width or pulse duty cycle reduced relative to the maximum value (pulse width or pulse duty cycle of the first driving signal D1). Whether it is the second driving signal D2 or the third driving signal D3, the mechanical energy transferred to the active element C-1 per pulse is less than in the case of the first driving signal D1. Therefore, the trajectories of the second amplitude A2 and the third amplitude A3 rise more slowly than those of the first amplitude A1, leveling off at a lower fixed or steady-state value. The time required to exceed the activation threshold At is longer than in the case of the first driving signal D1.

[0183] The amplitude of the vibration of the active element C-1 corresponds to the moving speed of the passive element C-4 relative to the active element C-1. That is, the larger the amplitude of the vibration of the active element C-1, the faster the moving speed of the passive element C-4 relative to the active element C-1. Therefore, by controlling the energy supplied to the active element C-1 with each pulse, the operating speed of the drive unit can be controlled. The energy supplied to the active element C-1 with each pulse corresponds to the shape of the pulse, and this shape is controlled by different types of modulation. For example, pulse amplitude modulation and / or pulse width modulation are known types of modulation.

[0184] If the energy transmitted to the active element C-1 by each pulse is too small, it is possible that the amplitude of the vibration of the active element C-1 will not exceed the activation threshold At at all, or will only occasionally and uncertainly exceed the activation threshold At. Therefore, the operating speed of the drive unit cannot be made higher than the speed threshold Vt (refer to...). Figure 22 Slow. Generally, the speed threshold Vt corresponds to the amplitude activation threshold At. The speed threshold Vt can be set within the range of 20% to 40% of the maximum speed, corresponding to the physical and electrical characteristics of the drive unit.

[0185] Figure 22 The above situation is illustrated by the relationship between pulse width or pulse duty cycle dp and the resulting speed v. If the pulse duty cycle dp is reduced from 50% of its maximum value, the operating speed of the drive unit decreases accordingly until it drops to the speed threshold Vt. If the pulse duty cycle dp is further reduced, the operating speed of the drive unit becomes zero.

[0186] To achieve a slower speed, the driving signal shape is maintained such that the amplitude of the vibration of the active element in a steady state, after adding a safety margin, is greater than the activation threshold At. For example... Figure 21 As shown, the drive unit operates intermittently. In this figure, along the same time axis t, the amplitude A4 of the vibration of the fourth drive signal D4 and the corresponding active element C-1, and the displacement S of the passive element C-4 relative to the corresponding active element C-1 are shown. Furthermore, compared to... Figure 20 The timeline is a compressed timeline.

[0187] In the fourth drive signal D4, pulses are included during the on-time and not during the off-time. The sequences with and without pulses repeat periodically with a pulse block period Tb equal to the on-time Ton + off-time Toff. The pulse block period is also called the excitation period. The repetition frequency fb = 1 / Tb corresponding to the pulse block period is called the pulse block frequency. The relationship between the on-time Ton and the pulse block period Tb, i.e., Ton / Tb, is called the pulse block duty cycle dpb.

[0188] Thus, pulses are applied to the drive unit only during the on-time period, while pulses are omitted or suppressed during the off-time period, thereby causing the drive unit to operate intermittently. During a sufficiently long on-time period, sufficient to cause the amplitude of the vibration of the active element C-1 to exceed the activation threshold At, the passive element C-4 is driven relative to the active element C-1 after a corresponding delay. During the off-time period after vibration decay, the active element C-1 holds the passive element C-4 in a fixed position through prestress. The displacement S increases through a series of steps and repetition during the steady-state period. Figure 21 The average slope of the displacement S shown represents the average velocity of the passive element C-4 relative to the active element C-1.

[0189] Generally speaking, velocity refers to the relative motion between the active element C-1 and the passive element C-4 as observed along a linear axis. In the case of a rotary drive unit, angular velocity corresponds to the value obtained by dividing the velocity by the radius when the active element C-1 drives the passive element C-4.

[0190] In typical applications, the pulse block period Tb corresponds to a pulse block frequency fb = 1 / Tb of 5kHz to 100kHz, typically around 25kHz. The frequency of the pulse itself is 50kHz to 1000kHz, typically around 500kHz.

[0191] The results show that the maximum speed is approximately 80 mm / s. The step size for each vibration cycle is in the range of 0.01–1 μm. The maximum force exerted by the active element C-1 on the passive element C-4 is 100 mN (i.e., a maximum of 0.1 N). The voltage applied to the excitation unit C-23 is approximately 3 V.

[0192] When the position of the drive unit needs to be obtained regardless of speed, the controller C-90 corrects the position change, i.e. the position step size, within one pulse cycle.

[0193] For example, the shape of the driving pulse is modified to reduce the energy transmitted by each pulse, thereby reducing the amplitude of the mechanical vibration of the driving passive element C-4.

[0194] Alternatively, the excitation frequency can be modified to reduce mechanical vibration, thereby reducing the transfer of energy to the amplitude, and / or the direction of mechanical vibration can be changed, i.e., the contribution of the driving force acting on the direction of motion of the passive element C-4 can be changed, thus making a modification.

[0195] Figure 23 The relationship between the excitation frequency f and the resulting velocity v is shown. At the first frequency f1, resonator C-2 is in the first operating mode or first vibration mode, driving the passive element C-4 at maximum velocity in the first direction. At the second frequency f2, resonator C-2 is in the second operating mode, driving the passive element C-4 at maximum velocity in the second direction opposite to the first direction. When the excitation frequency of the active element C-1 in each vibration mode is misaligned with its natural frequency, and there are slight deviations before or after f1 or f2 respectively, the respective velocities will decrease.

[0196] The examples above were illustrated in connection with a drive signal having a rectangular pulse. However, the same principle can be applied to pulses of different shapes, particularly in terms of amplitude and pulse width modulation and pulse omission. For example, the principle can also be applied to sine waves, triangular, trapezoidal, or sawtooth pulses, or pulses of arbitrary shapes.

[0197] The optimal excitation frequencies f1 and f2 for opposite-direction motion, as well as the excitation frequencies for different modes and directions, largely depend on the mechanical and electrical characteristics of the drive unit, especially the resonator C-2 and the excitation unit C-23. These characteristics change over time due to wear and parameter variations, environmental conditions such as temperature and humidity, and the orientation of the drive unit relative to the direction of gravity. Correspondingly, the optimal value of the excitation frequency also changes. To determine the optimal value, the drive unit can be operated at different frequencies, the target's response can be measured, and the frequency at which the target's response is optimal can be determined.

[0198] Figure 24 This is a flowchart showing the operation method of the drive unit of an embodiment. This process is executed by the controller C-90.

[0199] In the initialization step C-80, the method starts. In the measurement step C-81, the actual position of the drive unit, that is, the relative position between the active element C-1 and the passive element C-4, is determined. This position can be a rotational position or a translational position.

[0200] In the difference calculation step C-82, the difference d between the actual position and the set position is calculated. The difference d is represented by a position error signal. Depending on the value of the difference d, the method branches into different drive modes. According to different thresholds d1 < d2 < d3 and the absolute value abs(d) of the difference d, the drive unit is driven by drive signals with different parameters.

[0201] When abs(d) > d3 (in the determination step C-83, it is "y"), it is driven in the high-speed drive mode C-84. When d2 < abs(d) < d3 (in the determination step C-83, it is "n", and in the determination step C-85, it is "y"), it is driven in the medium-speed drive mode C-86. When d1 < abs(d) < d2 (in the determination step C-85, it is "n", and in the determination step C-87, it is "y"), it is driven in the low-speed drive mode C-88. In any of the above cases, the excitation frequency of the drive signal in the above example, that is, whether to use f1 or f2, is selected according to which direction the position should be corrected, that is, the positive or negative sign of the difference d.

[0202] When abs(d) < d1 (in the determination step C-87, it is "n"), the drive unit is not driven. At this time, in the braking mode C-89, the passive element C-4 is held on the active element C-1 by prestress.

[0203] Then, by continuing the measurement step C-81, this process is repeated.

[0204] The values of the position error thresholds d1 to d3 are selected when designing or ordering the drive unit. These values can be set, for example, as d1 = 1μm, d2 = 5μm, and d3 = 10μm.

[0205] In the embodiment, in the high-speed drive mode C-84, the pulse duty ratio with respect to the maximum power of the drive signal is typically 50%, and the maximum pulse block duty ratio is typically 100%.

[0206] In the medium-speed drive mode C-86, for example, the pulse duty cycle of the drive signal is reduced compared to the pulse duty cycle of the high-speed drive mode C-84. Alternatively, the pulse block duty cycle of the drive signal may be reduced compared to the pulse block duty cycle of the high-speed drive mode C-84.

[0207] In this implementation, both the pulse duty cycle and the pulse block duty cycle are reduced. For example, the pulse duty cycle is 30% (not the maximum of 50%), and the pulse block duty cycle is 50% (not the maximum of 100%).

[0208] In low-speed drive mode C-88, for example, the pulse duty cycle of the drive signal is reduced compared to the pulse duty cycle of medium-speed drive mode C-86. Alternatively, the pulse block duty cycle of the drive signal may be reduced compared to the pulse block duty cycle of medium-speed drive mode C-86.

[0209] In this implementation, both the pulse duty cycle and the pulse block duty cycle are reduced. For example, the pulse duty cycle is 20% (smaller than the pulse duty cycle in the medium-speed drive mode C-86), and the pulse block duty cycle is 10% (smaller than the pulse block duty cycle in the medium-speed drive mode C-86).

[0210] Thus, in this implementation, the pulse duty cycle of the drive signal in high-speed drive mode C-84 is 50%, and the pulse block duty cycle is 100%; the pulse duty cycle of the drive signal in medium-speed drive mode C-86 is 30%, and the pulse block duty cycle is 50%; and the pulse duty cycle of the drive signal in low-speed drive mode C-88 is 20%, and the pulse block duty cycle is 10%.

[0211] In this embodiment, the operation of the drive unit is controlled using three different drive modes: high-speed drive mode C-84, medium-speed drive mode C-86, and low-speed drive mode C-88. However, in another embodiment, the operation of the drive unit may be controlled using only two different drive modes.

[0212] Furthermore, while the implementation described controlling the operating speed of the drive unit by changing the pulse duty cycle and the pulse block duty cycle, it is also possible to adjust the pulse block frequency based on the difference d corresponding to the position error. For example, when the difference d is large, the pulse block frequency is set to 20-30 kHz in high-speed drive mode; when the difference d is small, the pulse block frequency is changed to 10-15 kHz in medium-speed or low-speed drive mode. By gradually reducing the pulse block frequency in this manner, the operating speed of the drive unit can be slowed down.

[0213] Specifically, when the pulse block frequency is set to 20kHz for a drive signal with a drive pulse of 700kHz, the number of pulses contained in a pulse block is 700kHz / 20kHz = 35 pulses when the pulse block duty cycle is 100%, 35 / 2 = 18 pulses when the pulse block duty cycle is 50%, and 18 / 2 = 9 pulses when the pulse block duty cycle is 25%.

[0214] In contrast, when the pulse block frequency is set to 10kHz relative to a drive signal of 700kHz, the number of pulses contained in a pulse block is 700kHz / 10kHz = 70 pulses when the pulse block duty cycle is 100%, 70 / 2 = 35 pulses when the pulse block duty cycle is 50%, 35 / 2 = 18 pulses when the pulse block duty cycle is 25%, and 18 / 8 = 9 pulses when the pulse block duty cycle is 12.5%.

[0215] That is, if the pulse block frequency is reduced, the number of pulses contained in a pulse block increases, thus widening the variable range of the pulse duty cycle. Therefore, the minimum settable pulse block duty cycle can be reduced, making it easier to slow down the operation speed of the drive unit.

[0216] Thus, the method of operating the drive unit of the present invention is a method of actuating the drive unit, which drives the passive element C-4 relative to the active element C-1. In this method, the active element C-1 includes a resonator C-2 and at least one excitation unit C-23 that excites the vibration of the resonator C-2. The resonator C-2 includes at least one arm C-21 extending from the connecting portion C-20 of the resonator C-2. The at least one arm C-21 has a contact portion C-31 at its outer end, and the contact portion C-31 is movable by the vibrational movement of the at least one arm C-21. The passive element C-4 is configured to move relative to the active element C-1, driven by the vibrational movement. In addition, the passive element C-4 has a first contact area C-41, which is configured to contact the first contact portion C-31. The active element C-1 and the passive element C-4 are configured such that, when the active element C-1 is not activated, at least the first contact portion C-31 is pressed against the first contact area C-41 due to prestress.

[0217] Furthermore, the operation method of the drive unit includes the following steps: driving the excitation unit C-23 with a drive signal and repeatedly omitting drive pulses to generate a periodically repeating pulse block, wherein the drive signal is a periodic signal containing drive pulses that repeat at the excitation frequency, and the relationship between the pulse block on-time Ton and the pulse block period Tb, Ton / Tb, is used as the pulse block duty cycle; and the drive signal is corrected in accordance with the position error signal.

[0218] In the step of correcting the drive signal, if the position error signal is within a first range, the shape of the drive pulse is corrected in such a way that the shape of the drive pulse becomes the shape of a first drive pulse, or the excitation frequency is corrected according to the first excitation frequency offset value, and the pulse block duty cycle is set to the first pulse block duty cycle value. Figure 24 (C-83, C-84) When the position error signal is within the second range, the shape of the drive pulse is corrected in such a way that the shape of the drive pulse becomes the shape of the second drive pulse, or the excitation frequency is corrected according to the second excitation frequency offset value, and the pulse block duty cycle is set to the second pulse block duty cycle value. Figure 24 (C-85, C-86).

[0219] By repeatedly omitting drive pulses to achieve different pulse block duty cycle values, this corresponds to a correction of the duration Toff of the omitted drive pulse disconnection period based on the position error signal. This allows for quasi-continuous driving of the passive element C-4 at a relatively slow average speed. Consequently, compared to speeds achievable simply by reducing the shape of the drive pulses, a further reduction in speed is possible, enabling the achievement of a given speed setpoint. Such a speed allows the energy of the drive pulses to be reduced to below the threshold required for reliable operation of the drive unit. At higher speeds, the speed can be controlled by the shape of the drive pulses.

[0220] By using different combinations of drive pulse shape (or excitation frequency offset value) and pulse block duty cycle, the movement speed of the drive unit toward the set point (target position) can be made to match the magnitude of the position error signal. The result is that the position control of the drive unit can be performed both quickly and accurately.

[0221] Throughout this specification, when referring to the speed and position of the drive unit, the overall meaning refers to the speed or position of the passive element C-4 relative to the active element C-1. The motion can be linear, rotational, or a combination thereof, depending on the mechanical structure and excitation method.

[0222] In one embodiment, the driving unit is a piezoelectric driving unit, and the excitation unit C-23 is a piezoelectric element. In another embodiment, an electromagnetic actuator (voice coil, etc.), a magnetostrictive actuator, or an actuator with a shape memory alloy base can be used as the driving unit.

[0223] Typically, as described in Patent Document 1 or Patent Document 2, the movement of the contact portion C-31 is achieved by applying a force to the passive element C-4 repeatedly to move the passive element C-4, and the direction of movement can be controlled by the excitation frequency of the excitation unit C-23.

[0224] Therefore, the active element C-1 can drive the passive element C-4 in accordance with the excitation frequency, causing it to move in a first direction or a second direction opposite to the first direction. In one embodiment, the motion performed by the passive element C-4 is a translational motion. In another embodiment, the motion is a rotational motion. In one embodiment, the resonator C-2 and its components are made of a single sheet material, especially a thin sheet of metal.

[0225] In this implementation, when the position error signal is within a third range, the shape of the drive pulse is corrected to make the shape of the drive pulse become the shape of the third drive pulse, or the excitation frequency is corrected according to the third excitation frequency offset value, and the pulse block duty cycle is set to the third pulse block duty cycle value. Figure 24 Steps C-87 to C-88).

[0226] In this implementation, the shape of the driving pulse is corrected by at least one of correcting the amplitude of the driving pulse and correcting the pulse width of the driving pulse.

[0227] In the implementation, in any case, the excitation frequency is kept constant during the correction of the shape of the drive pulse, and the energy transmitted through each drive pulse is kept higher than the minimum pulse energy value, which is a value other than zero.

[0228] By maintaining the duty cycle of the driving pulses higher than the minimum pulse duty cycle and the amplitude of the driving pulses higher than the minimum amplitude, it is achieved that the energy transmitted through each driving pulse is kept higher than the minimum pulse energy value, which is a value other than zero.

[0229] In this embodiment, the minimum pulse energy value is at least 5% of the maximum pulse energy, preferably at least 10%.

[0230] In this implementation, the correction of the excitation frequency includes a correction in which, without changing the vibration mode, the excitation frequency is corrected only by reducing the amount by which the matching between the excitation frequency and the natural frequency of the drive unit is reduced within that vibration mode. This reduces the energy transfer to the mechanical vibration, resulting in a reduction in amplitude.

[0231] In the implementation, the drive pulse is repeatedly omitted, and during the disconnection period of the omitted drive pulse, the position of the passive element C-4 relative to the active element C-1 is maintained by prestress.

[0232] In the implementation, for the amplitude of the active element C-1 driving the passive element C-4 by the vibration of the active element C-1, it is sufficient to repeatedly omit the duration Ton of the on-time of the applied drive pulse when the drive pulse is applied.

[0233] In the implementation, the excitation frequency is in the range of 50kHz to 1000kHz, and the drive pulses are repeatedly omitted at a frequency of 1 / 10 to 1 / 100 of the excitation frequency.

[0234] In the implementation, the first range is higher than the second range, the energy of the driving pulse with the first driving pulse shape is greater than the energy of the driving pulse with the second driving pulse shape, and the duty cycle of the first pulse block is greater than the duty cycle of the second pulse block.

[0235] Therefore, when the position error signal value is high, i.e., when the position error signal is within the first range, the operating speed of the drive unit is higher than when the position error signal is within the second range. This is because, when the position error signal is within the first range, the energy of the drive pulse is greater, and / or the pulse block duty cycle is larger, compared to when it is within the second range.

[0236] In this implementation, the first driving pulse shape is a rectangular pulse with a duty cycle of 50%, and the first pulse block duty cycle is 100%. This corresponds to a rectangular pulse sequence with maximum power relative to a given peak voltage of the signal.

[0237] In the implementation, the second range is higher than the third range, the energy of the driving pulse with the second driving pulse shape is greater than the energy of the driving pulse with the third driving pulse shape, and the duty cycle of the second pulse block is greater than the duty cycle of the third pulse block.

[0238] Therefore, when the position error signal value is small, i.e., when the position error signal is within the third range, the operating speed of the drive unit is lower than when the position error signal is within the second range. This is because, when the position error signal is within the third range, the energy of the drive pulse is smaller, and / or the pulse block duty cycle is smaller, compared to when it is within the second range.

[0239] In this implementation, the method for operating the drive unit includes setting the frequency of the excitation frequency according to the sign of the position error signal. Therefore, the direction of motion can be changed by selecting the excitation frequency, and the direction of motion can be set according to the direction in which the drive unit needs to move to reduce the position error.

[0240] In this embodiment, the driving unit is operated such that it drives the passive element C-4 relative to the active element C-1. The active element C-1 includes a resonator C-2 and at least one excitation unit C-23 that excites the vibration of the resonator C-2. The resonator C-2 includes at least two arms C-21 and C-22 extending from the connecting portion C-20 of the resonator C-2. Arms C-21 and C-22 have contact portions C-31 and C-32 at their outer ends, respectively. The contact portions C-31 and C-32 are movable by the vibrational movement of each arm C-21 and C-22. The passive element C-4 is configured to be driven relative to the active element C-1 by these vibrational movements, thereby moving. Furthermore, the passive element C-4 includes a first contact area C-41 and a second contact area C-42, each contact area C-41 and C-42 being configured to contact each of the first contact portion C-31 and the second contact portion C-32. The active element C-1 and the passive element C-4 are configured such that, especially when the active element C-1 is not activated, the first contact portion C-31 and the second contact portion C-32 are pressed against the respective first contact area C-41 and second contact area C-42 due to prestress.

[0241] In this embodiment, the second arm C-22 is configured to move in a vibrational motion that is balanced with the vibrational motion of the first arm C-21. That is, when the excitation unit C-23 is excited at a frequency that drives the passive element C-4 relative to the active element C-1, the first arm C-21 and the second arm C-22 vibrate through a motion that is balanced with each other.

[0242] Typically, the resonator C-2 of the type described in this specification has a resonator axis corresponding to the axis of symmetry of the geometry of the resonator C-2. In the case of a resonator C-2 that is generally planar in shape, the resonator axis lies in its reference plane. The symmetry with respect to the resonator axis can be understood as a symmetry corresponding to the general shape of arms C-21 and C-22; however, there may be imperfections in the symmetry for minor details of the shape of arms C-21 and C-22.

[0243] Therefore, when at least two arms C-21, C-22 extend substantially symmetrically from the connecting portion C-20, subtle differences may exist in their shape or profile. For example, when measurements are taken in the direction in which arms C-21, C-22 extend, one arm (e.g., the first arm C-21) may be shorter than the other arm (e.g., the second arm C-22). For example, one arm may be shorter than the other by a maximum of 10%, 20%, 30%, or 40%.

[0244] Arms C-21 and C-22, which are symmetrically arranged about the resonator axis or symmetry point, can balance each other's motions during vibration. As a result, the vibrational motion of resonator C-2 is essentially symmetrical about the resonator axis.

[0245] In this implementation, the connecting portion C-20 is essentially rectangular in shape. Typically, the excitation unit C-23 is also essentially rectangular. The sides of the rectangle corresponding to the rectangular approximation of the connecting portion C-20 can be aligned parallel to the sides of the rectangle corresponding to the rectangular approximation of the excitation unit C-23.

[0246] The resonator C-2 and its components are of a single, integral shape. In other words, the components of the resonator C-2, such as the connecting part C-20, the first arm C-21 and the second arm C-22, the mounting area, and the optional bearing arm, are manufactured as a single piece. This can be achieved, for example, by punching or cutting the resonator C-2 from a sheet of metal, or by casting, or by additional manufacturing processes.

[0247] In addition, in this embodiment, the controller C-90 is a controller configured to execute the above-described operation method of the drive unit. It is connected to the excitation unit C-23 of the drive unit and supplies power to the excitation unit C-23. It reads the signal from the sensor 91 and determines the position of the drive unit.

[0248] Further embodiments of the controller C-90 can be derived from the dependent claims of the method claims. Furthermore, features of the method claims can be combined with features of the apparatus claims, and vice versa.

[0249] The invention made by the inventor has been specifically described above based on the embodiments, but the invention is not limited to the above embodiments and can be modified within the scope of its essential points.

[0250] For example, in this embodiment, a smartphone M, a portable terminal with a camera, was described as an example of a camera-mounted device equipped with a camera module A. However, the present invention can be applied to camera-mounted devices having a camera module and an image processing unit that processes image information obtained by the camera module. The camera-mounted device includes information equipment and transportation equipment. Information equipment includes, for example, a mobile phone with a camera, a laptop computer, a tablet computer, a portable game console, a webcam, and a vehicle-mounted device with a camera (e.g., a rear-view camera, a dashcam). Transportation equipment includes, for example, a car.

[0251] Figure 25A , Figure 25B This is a diagram of a car V, which is a camera mounting device that includes a vehicle camera module (VC). Figure 25A This is the front view of car V. Figure 25B This is a rear perspective view of vehicle V. Vehicle V is equipped with camera module A, as described in the embodiment, which serves as an in-vehicle camera module VC. Figure 25A , Figure 25B As shown, the vehicle-mounted camera module VC can be mounted forward on the windshield or rearward on the tailgate. This vehicle-mounted camera module VC is used for rear monitoring, dashcams, collision avoidance control, and autonomous driving control, among other applications.

[0252] In another embodiment, the first arm 141b of the AF drive unit 14 abuts against the AF force-applying members 112 and 512 constituting the AF movable parts 11 and 51. However, the first arm 141b of the AF drive unit 14 may also abut directly against the lens holders 111 and 511. However, compared to abutting against the lens holders 111 and 511, which are made of resin molded parts, abutting against the AF force-applying members 112 and 512, which are made of metal molded parts, can transmit driving force more efficiently and improve durability.

[0253] Alternatively, force-applying components that apply force to the lens brackets 111 and 511 toward the first stage 12 and components that abut against the first arm 141b of the AF drive unit 14 can be provided separately.

[0254] In addition, in the embodiment, two AF drive units 14A and 14B are provided, but as long as the driving force that can make the AF movable parts 11 and 51 move in the Z direction can be exerted, the number of AF drive units 14 can be one or more.

[0255] Furthermore, the present invention can be applied not only to autofocus, but also to zoom and other applications where the movable part moves along the optical axis.

[0256] Furthermore, the support structure of the AF movable part 51 using the AF force application member 512 in the second embodiment is not limited to being applied to the case where the drive source is an ultrasonic motor, such as the AF drive part 14, but can also be applied to lens drive devices that have a drive source other than an ultrasonic motor (e.g., a voice coil motor (VCM)).

[0257] The embodiments disclosed herein should be considered illustrative in all respects and not intended to be limiting. The scope of the invention is not defined by the foregoing description, but by the claims of this application, and includes all modifications within the meaning and scope equivalent to the claims.

[0258] The entire contents of the description, drawings and abstract of Japanese Patent Application No. 2019-225710, filed on December 13, 2019, are incorporated herein by reference.

[0259] Explanation of reference numerals in the attached figures

[0260] 1.1A Lens Driving Device

[0261] 10. 10A OIS movable part (second movable part)

[0262] 11.51 AF movable part (first movable part)

[0263] 111, 511 Lens Support

[0264] 112, 512 AF force application components

[0265] 12 First Unit (First Fixed Unit)

[0266] 13 Second Department

[0267] 14 AF Drive Unit (Z-direction Drive Unit)

[0268] 141 AF resonance section

[0269] 142 AF piezoelectric element

[0270] 143 AF electrode

[0271] 15 AF Support Section (First Support Section)

[0272] 20 OIS fixing part (second fixing part)

[0273] 21 Base

[0274] 30 OIS Drive Unit (XY Direction Drive Unit)

[0275] 31 OIS Resonance Section

[0276] 32 OIS piezoelectric element

[0277] 33 OIS electrode

[0278] 34 OIS Power Transmission Unit

[0279] 40 OIS Support Section (Second Support Section)

[0280] 50 OIS force application components

[0281] A camera module

[0282] M Smartphone (Camera-mounted device)

Claims

1. A method of operating a drive unit, the method being a method of operating a drive unit that drives a passive element with respect to an active element, in the method, the active element includes a resonator and at least one excitation unit that excites vibration of the resonator, the resonator includes at least one arm that extends from a connection portion of the resonator, the at least one arm includes a contact portion at an outer end of the at least one arm, the contact portion is movable by a vibration motion of the at least one arm, the contact portion includes a first contact portion, the passive element is configured to be moved with respect to the active element by the vibration motion, the passive element has a first contact region that is configured to be in contact with the first contact portion, the active element and the passive element are configured such that, when the active element is not excited, at least the first contact portion is pressed toward the first contact region by a pre-stress, the method of operating the drive unit includes the following steps: a step of driving the excitation unit with a drive signal that is a periodic signal including drive pulses that are repeated at an excitation frequency, and repeatedly omitting the drive pulses, thereby generating a pulse block that is periodically repeated, wherein a relationship Ton / Tb between a turn-on time Ton of the pulse block and a pulse block period Tb is a pulse block duty ratio; and a step of correcting the drive signal in correspondence with a position error signal, in the step of correcting the drive signal, when the position error signal is within a first range, the pulse block duty ratio is set to a first pulse block duty ratio value and the drive signal is corrected in such a manner that a shape of the drive pulse is corrected to a first drive pulse shape or the excitation frequency is corrected according to a first excitation frequency detuning value, when the position error signal is within a second range, the pulse block duty ratio is set to a second pulse block duty ratio value and the drive signal is corrected in such a manner that the shape of the drive pulse is corrected to a second drive pulse shape or the excitation frequency is corrected according to a second excitation frequency detuning value, the first range is higher than the second range, an energy of the drive pulse having the first drive pulse shape is greater than an energy of the drive pulse having the second drive pulse shape, the first pulse block duty ratio value is greater than the second pulse block duty ratio value.

2. The method of operating the drive unit according to claim 1, wherein, in the step of correcting the drive signal, when the position error signal is within a third range, the shape of the drive pulse is corrected to a third drive pulse shape or the excitation frequency is corrected according to a third excitation frequency detuning value, and the pulse block duty ratio is set to a third pulse block duty ratio value.

3. The method of operating the drive unit according to claim 1, wherein, the correction of the shape of the drive pulse is performed by at least one of a correction of an amplitude of the drive pulse and a correction of a pulse width of the drive pulse.

4. The operation method of the drive unit according to claim 1, wherein In either case, the excitation frequency is kept constant in the modification of the shape of the drive pulse, and the energy delivered by each drive pulse is kept higher than a minimum pulse energy value, which is a value other than zero.

5. The operation method of the drive unit according to claim 4, wherein The minimum pulse energy value is at least 5% of the maximum energy of the drive pulse.

6. The operation method of the drive unit according to claim 1, wherein In the omission of the off period of the drive pulse, the position of the passive element relative to the active element is maintained by the pre-stress.

7. The operation method of the drive unit according to claim 1, wherein The excitation frequency is in the range of 50 kHz to 1000 kHz, and the omission of the repetition of the drive pulse is performed at a frequency of 1 / 10 to 1 / 100 of the excitation frequency.

8. The operation method of the drive unit according to claim 1, wherein The drive pulse having the first drive pulse shape is a rectangular pulse with a pulse duty ratio of 50%, and the first pulse block duty ratio value of the drive pulse having the first drive pulse shape is 100%.

9. The operation method of the drive unit according to claim 2, wherein The second range is higher than the third range, The energy of the drive pulse having the second drive pulse shape is greater than the energy of the drive pulse having the third drive pulse shape, The second pulse block duty ratio value is greater than the third pulse block duty ratio value.

10. The method of Claim 1, wherein the drive unit is a motor. comprising the steps of: The frequency of the excitation frequency is set in correspondence with the sign of the position error signal.

11. The operation method of the drive unit according to claim 1, wherein The resonator is provided with at least two arms extending from the joint portion of the resonator, The arms have the contact portions at the outer ends of the arms, The contact portions include a first contact portion and a second contact portion, The passive element has a first contact region and a second contact region, each contact region being disposed in contact with each of the first contact portion and the second contact portion, The active element and the passive element are disposed such that, when the active element is not excited, the first contact portion and the second contact portion are pressed toward the first contact region and the second contact region, respectively, by a pre-stress.

12. A controller configured to execute the method according to any one of claims 1 to 11, The controller is connected to and supplies power to the excitation unit of the drive unit, reads a signal from a sensor, and determines the position of the drive unit.

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