Guide unit, and actuator, lens unit, and imaging device equipped therewith.

Abstract

The present invention provides a guide unit that can guide the movement of movable parts with sufficient precision while also being miniaturized. [Solution] The present invention provides a guide unit (18) for guiding the movement of a movable part relative to a fixed part in two directions, comprising: a shaft (30) attached to one of the fixed part (12) or the movable part (14) so ​​as to extend in a first direction; a main body (31) arranged to surround the shaft; three or more rolling balls (33) each arranged at both ends of the main body so as to surround the shaft; and retainers (32) attached to both sides of the main body, which hold the rolling balls in the main body so that each rolling ball can roll around the shaft, wherein the main body and / or retainers are provided with rolling surfaces (32c) that can contact the other surface of the fixed part or the movable part and roll in a second direction.

Description

Technical Field

[0001] The present invention relates to a guide unit, and particularly to a guide unit that guides the movement of a movable part with respect to a fixed part in two directions, and an actuator, a lens unit, and an imaging device including the same.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2023-46735 (Patent Document 1) describes a lens barrel and an imaging device. The lens barrel described herein includes a shake correction device, and this shake correction device is configured to drive a movable frame holding a lens in a direction intersecting the optical axis.

[0003] The shake correction device includes a rotation restriction mechanism including two shafts extending in parallel and a swing member attached to connect these two shafts. The first shaft of the rotation restriction mechanism is attached to the movable frame, and one end of the swing member is rotatably attached to this first shaft. On the other hand, the second shaft is attached to the fixed frame, and this second shaft is received in a groove provided at the other end of the swing member. By the rotation restriction mechanism configured in this way, the movement of the movable frame with respect to the fixed frame is restricted in the directions in which the first and second shafts are directed and in the directions perpendicular to these shafts.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the rotation regulating mechanism in the image stabilization device described in Patent Document 1 connects the fixed frame and the movable frame via multiple members, thereby regulating the rotation of the movable frame. As a result, there is a problem that the rotation of the movable frame cannot be regulated with sufficient precision due to the play present in the connection parts between each member. Furthermore, in the image stabilization device described in Patent Document 1, in order to ensure a large stroke of the movable frame relative to the fixed frame, it is necessary to make the oscillating member long, which presents a problem in that it is difficult to miniaturize the image stabilization device in the optical axis direction.

[0006] Therefore, the present invention aims to provide a guide unit that can guide the movement of a movable part with sufficient precision and can be miniaturized, as well as an actuator, lens unit, and imaging device equipped therewith. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the present invention provides a guide unit for guiding the movement of a movable part relative to a fixed part in two directions, comprising: a shaft attached to one of the fixed part or the movable part so as to extend in a first direction; a main body arranged so as to surround the shaft; three or more rolling balls arranged at each end of the main body so as to surround the shaft; and retainers attached to both sides of the main body, respectively, which hold the rolling balls in the main body so that each rolling ball can roll around the shaft, wherein the main body and / or retainers are provided with rolling surfaces that can contact the other surface of the fixed part or the movable part and roll in a second direction.

[0008] In the present invention configured as described above, since three or more rolling balls are held rotatably around the shaft, the movable part can slide smoothly relative to the fixed part in the first direction, which is the axial direction of the shaft. Furthermore, since rolling surfaces that can roll in a second direction are provided around the main body and / or retainer, the movable part can slide smoothly relative to the fixed part in the second direction as the rolling surfaces roll around the shaft. This allows the movement of the movable part to be guided with sufficient precision and enables the guide unit to be miniaturized.

[0009] Furthermore, the present invention is an actuator for moving a lens or lens group in a plane perpendicular to the optical axis, characterized by comprising: a fixed part; a movable part supported relative to the fixed part so as to be movable in a plane perpendicular to the optical axis; a movable part drive mechanism for moving the movable part relative to the fixed part in a plane perpendicular to the optical axis; and a guide unit of the present invention for guiding the movement of the movable part relative to the fixed part in a first direction and a second direction perpendicular to the first direction.

[0010] Furthermore, the present invention is a lens unit for use attached to an imaging device, characterized by comprising a lens barrel and an actuator of the present invention for moving a lens or lens group arranged inside the lens barrel in a plane perpendicular to the optical axis.

[0011] Furthermore, the present invention is an imaging device for capturing video or still images, characterized by comprising a lens unit of the present invention and an imaging device body to which the lens unit is attached. [Effects of the Invention]

[0012] According to the present invention, the guide unit, and the actuator, lens unit, and imaging device equipped therewith, the movement of the movable part can be guided with sufficient precision, and the guide unit can be miniaturized. [Brief explanation of the drawing]

[0013] [Figure 1] Cross-sectional view of an imaging device according to the first embodiment of the present invention. [Figure 2] Perspective view of an actuator according to the first embodiment of the present invention. [Figure 3] Perspective view showing the fixing portion of the actuator according to the first embodiment of the present invention. [Figure 4] Perspective view of the movable portion of the actuator according to the first embodiment of the present invention as viewed from the side facing the fixing portion. [Figure 5] Perspective view of the movable portion of the actuator according to the first embodiment of the present invention as viewed from the side opposite to the fixing portion. [Figure 6] Perspective view of a guide unit according to the first embodiment of the present invention. [Figure 7] Exploded perspective view of a guide unit according to the first embodiment of the present invention. [Figure 8] Perspective view of an actuator provided in an imaging device according to the second embodiment of the present invention. [Figure 9] Exploded perspective view of an actuator provided in an imaging device according to the second embodiment of the present invention. [Figure 10] Perspective view of a guide unit provided in the actuator according to the second embodiment of the present invention. [Figure 11] Exploded perspective view showing a modified example of a guide unit according to the second embodiment of the present invention. [Figure 12] Exploded perspective view showing a second modified example of a guide unit according to the second embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0014] (First Embodiment) Next, embodiments of the present invention will be described with reference to the accompanying drawings. First, an imaging device according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a cross-sectional view of an imaging device according to the first embodiment of the present invention.

[0015] <Configuration of Imaging Device> As shown in FIG. 1, the imaging device 1 according to the first embodiment of the present invention includes a lens unit 2 and an imaging device main body 4. The lens unit 2 includes a lens barrel 6, a plurality of lenses 8 disposed therein, and an actuator 10 that moves the shake correction lens 16 in a plane orthogonal to the optical axis A. Further, the lens unit 2 includes a gyro 34 that is a vibration detection means for detecting vibration of the lens barrel 6, and a controller 36 that controls the actuator 10 based on the detection signal of the gyro 34.

[0016] The imaging device 1 according to the first embodiment of the present invention detects vibration by the gyro 34, operates the actuator 10 based on the detected vibration to move the shake correction lens 16, and stabilizes an image focused on the imaging element surface 4a in the imaging device main body 4. In the present embodiment, a piezoelectric vibration gyro is used as the gyro 34. In the present embodiment, the shake correction lens 16 is constituted by a single lens, but the lens for stabilizing the image may be a plurality of lens groups. In this specification, the shake correction lens includes a single lens and a lens group for stabilizing an image.

[0017] The lens unit 2 is attached to the imaging device main body 4 and is configured to form an image of incident light on the imaging element surface 4a. The substantially cylindrical lens barrel 6 holds a plurality of lenses 8 therein and enables focusing adjustment by moving some of the lenses 8.

[0018] <Configuration of Actuator> Next, the actuator 10 according to the first embodiment of the present invention will be described with reference to FIGS. 2 to 7. FIG. 2 is a perspective view of the actuator 10. FIG. 3 is a perspective view showing the fixed portion of the actuator 10. FIG. 4 is a perspective view of the movable portion of the actuator 10 as seen from the side facing the fixed portion. FIG. 5 is a perspective view of the movable portion of the actuator 10 as seen from the side opposite to the fixed portion.

[0019] As shown in Figure 2, the actuator 10 includes a fixed plate 12, which is a fixed part fixed inside the lens barrel 6, and a movable frame 14, which is a movable part supported movably relative to the fixed plate 12. Furthermore, the actuator 10 includes two support balls 17 (Figure 3) sandwiched between the fixed plate 12 and the movable frame 14, and a guide unit 18 that guides the movement of the movable frame 14 relative to the fixed plate 12. In addition, a vibration correction lens 16 is mounted in the center of the movable frame 14, and the two support balls 17 and the guide unit 18 are arranged around it. As a result, the movable frame 14 is supported on a plane parallel to the fixed plate 12 and perpendicular to the optical axis A of the vibration correction lens 16, and translational movement of the movable frame 14 in any direction relative to the fixed plate 12 is permitted. The specific configuration of the guide unit 18 will be described later.

[0020] Next, as shown in Figure 3, the fixing plate 12, which is the fixed part, is a roughly circular, donut-shaped plate fixed inside the lens barrel 6. Three drive coils 20 and two magnetic sensors 24 are mounted on this fixing plate 12. Furthermore, the fixing plate 12 is provided with a receiving recess 12a into which the guide unit 18 abuts and rolls.

[0021] The three drive coils 20 are fixed to the fixing plate 12 so as to face each of the three magnet assemblies 22 (Figure 2) attached to the movable frame 14. That is, each drive coil 20 is a flat coil wound into a rectangle with rounded corners. Furthermore, each drive coil 20 is attached to the fixing plate 12 such that the longer side of the rectangle is oriented in the radial direction of a circle centered on the optical axis A, and is arranged on the circumference of the circle centered on the optical axis A at intervals of approximately 120 degrees at a central angle.

[0022] Furthermore, two cylindrical ball receivers 12b are provided between the drive coils 20 of the fixed plate 12, and support balls 17 are placed inside these ball receivers 12b, thereby supporting the movable frame 14 so that it can move. In other words, the fixed plate 12 has two ball receivers 12b and a receiving recess 12a, each positioned between the three drive coils 20.

[0023] Furthermore, rectangular plate-shaped back yokes 26 are attached to the back side of each drive coil 20 of the fixed plate 12. These back yokes 26 guide the magnetism of each magnet assembly 22 attached to the movable frame 14 to each drive coil 20, and the magnetic force acting between the back yokes 26 and the magnet assembly 22 attracts the movable frame 14 to the fixed plate 12. Due to this attractive force, the support ball 17 is sandwiched between the movable frame 14 and the fixed plate 12, and the guide unit 18 is pressed against the receiving recess 12a.

[0024] Furthermore, the fixing plate 12 is provided with a shelf portion 19 so as to cover the receiving recess 12a. This shelf portion 19 is a flat plate that extends in an arc shape and is attached to one location on the outer circumference of the fixing plate 12, and is supported so as to extend parallel to the fixing plate 12. A guide unit 18 attached to the movable frame 14 is positioned between this shelf portion 19 and the fixing plate 12. Magnetic sensors 24 are also attached to two locations on the shelf portion 19.

[0025] On the other hand, as shown in Figures 4 and 5, the movable part, the movable frame 14, is a roughly circular, donut-shaped plate supported parallel to the fixed plate 12. A vibration correction lens 16 is attached to the circular opening in the center of this movable frame 14. Three magnet assemblies 22 and two position detection magnets 28 are also attached to this movable frame 14. A cylindrical ball receiver 14b is formed on the movable frame 14 between the three magnet assemblies 22, at a position opposite the receiving recess 12a of the fixed plate 12 (Figure 4). Furthermore, a guide unit 18 is attached to the movable frame 14.

[0026] The three magnet assemblies 22 are mounted at equal intervals on the circumference of the movable frame 14. That is, the three magnet assemblies 22 are mounted on the movable frame 14 at intervals of approximately 120 degrees on the circumference of a circle centered on the optical axis A, so as to face each of the three drive coils 20. Each magnet assembly 22 consists of a rectangular metal plate yoke 22a and two rectangular plate-shaped drive magnets 22b and 22c mounted on the back side of the yoke 22a. The drive magnets 22b and 22c mounted on the back side of the yoke 22a are positioned to face the drive coils 20 mounted on the fixed plate 12 (Figure 2). The combination of each magnet assembly 22 and each drive coil 20 positioned opposite them functions as a movable part drive mechanism that moves the movable frame 14 in a plane perpendicular to the optical axis A relative to the fixed plate 12.

[0027] In other words, when current flows through the drive coil 20, an electromagnetic force acts on the opposing magnet assembly 22, generating a driving force on the movable frame 14. Thus, in this embodiment, the actuator 10 is equipped with three movable part drive mechanisms. In this embodiment, these movable part drive mechanisms are configured to generate thrust in the tangential direction of a circle centered on the optical axis A of the vibration correction lens 16, within a plane perpendicular to the optical axis A. That is, the directions of action of the driving forces generated by the three movable part drive mechanisms are different from each other.

[0028] Next, as shown in Figure 5, a guide unit support portion 14a for supporting the guide unit 18 is provided at one location on the outer circumference of the movable frame 14. This guide unit support portion 14a is a gate-shaped portion provided on the movable frame 14 and supports the guide unit 18 on its inside. The guide unit support portion 14a and the guide unit 18 provided on the movable frame 14 are inserted between the receiving recess 12a of the fixed plate 12 and the shelf portion 19, and the guide unit 18 supported by the movable frame 14 comes into contact with the receiving recess 12a of the fixed plate 12 (Figure 2).

[0029] Furthermore, two rectangular plate-shaped position-detecting magnets 28 are attached to the upper side of the guide unit support portion 14a (opposite the guide unit 18). These two position-detecting magnets 28 are positioned to face two magnetic sensors 24 attached to the shelf portion 19 of the fixed plate 12. Each magnetic sensor 24 has a magnetization boundary line (boundary line between the south pole and the north pole) extending in a plane perpendicular to the optical axis A, and by detecting the magnetism of the opposing position-detecting magnets 28, the position of the movable frame 14 relative to the fixed plate 12 can be detected.

[0030] Specifically, each magnetic sensor 24 is positioned to face the magnetization boundary line of each position-detecting magnet 28, and can measure the distance from the magnetization boundary line. Since the two position-detecting magnets 28 are positioned so that their magnetization boundary lines are perpendicular to each other, each magnetic sensor 24 can detect the movement distance of the movable frame 14 in two directions that are perpendicular to each other. In this embodiment, each magnetic sensor 24 is composed of a Hall element.

[0031] <Guide Unit Configuration> Next, the configuration of the guide unit 18 will be explained with new reference to Figures 6 and 7. Figure 6 is a perspective view of the guide unit 18 according to the first embodiment of the present invention. Figure 7 is an exploded perspective view of the guide unit 18 according to the first embodiment of the present invention.

[0032] As shown in Figure 6, the guide unit 18 includes a shaft 30 attached to the movable frame 14, a main body 31 arranged to surround the shaft 30, and retainers 32 attached to both sides of the main body 31. Furthermore, as shown in Figure 7, four rolling balls 33 are arranged at each end of the main body 31, surrounding the shaft 30. In this embodiment, the rolling balls 33 are metal spheres and are held between the main body 31 and each retainer 32 so that they can roll around the shaft 30.

[0033] The shaft 30 is a metal shaft with a circular cross-section, and both ends are held by guide unit support portions 14a provided on the movable frame 14 (Figure 4). In this embodiment, the shaft 30 is attached to the movable frame 14 facing the first direction. On the other hand, as described above, two position detection magnets 28 (Figure 5) are attached to the guide unit support portions 14a of the movable frame 14. Therefore, the metal shaft 30 attached to the guide unit support portions 14a is attracted toward the position detection magnets 28 by magnetic force. As a result, the shaft 30 is assembled to the movable frame 14 without any play.

[0034] As described above, the position detection magnet 28 is provided to detect magnetism using the magnetic sensor 24 and determine the position of the movable frame 14. The shaft 30 of the guide unit 18 is attracted toward the movable frame 14 by this position detection magnet 28. In other words, in this embodiment, the magnet for position detection and the magnet for attracting the shaft 30 are used for both purposes. However, if the position detection magnet 28 is attached to another location, or if the position detection magnet 28 is not used, a dedicated magnet for attracting the shaft 30 can be provided. Alternatively, the magnet for attracting the shaft 30 can be omitted.

[0035] Next, as shown in Figure 7, the main body 31 is a cylindrical resin component and is arranged to surround the shaft 30. Furthermore, four ball receiving recesses 31a for receiving the rolling balls 33 are formed on both end faces of the main body 31 (only one side is shown in Figure 7). These ball receiving recesses 31a have a roughly fan-shaped cross-section when viewed from the axial direction of the shaft 30.

[0036] Furthermore, the outer circumferential surface of the main body 31 is provided with four pin receiving grooves 31b extending in the axial direction. These four pin receiving grooves 31b have a substantially semicircular cross-section and are formed at equal intervals on the outer circumferential surface of the main body 31. The four pins 32b formed in each retainer 32 are inserted into these pin receiving grooves 31b from both sides of the main body 31.

[0037] Next, the two retainers 32 are, as a whole, truncated cone-shaped resin components, and are attached to both ends of the main body 31 so as to surround the shaft 30. Furthermore, four ball receiving recesses 32a for receiving the rolling balls 33 are formed inside each retainer 32 (only one side is shown in Figure 7). These ball receiving recesses 32a are provided opposite each ball receiving recess 31a of the main body 31 and have a substantially fan-shaped cross-section when viewed from the axial direction of the shaft 30.

[0038] The rolling balls 33 are held at equal intervals around the shaft 30 by ball receiving recesses 31a provided on the end face of the main body 31 and ball receiving recesses 32a provided on the inside of each retainer 32. That is, the four rolling balls 33 are held around the shaft 30 at 90-degree intervals. In this embodiment, four rolling balls 33 are arranged around the shaft 30, but the number of rolling balls 33 can be three or more, and can be set to any number.

[0039] Furthermore, each rolling ball 33 is in point contact with the shaft 30 while being held around the shaft 30. When the main body 31 and retainer 32 are rotated relative to the shaft 30, each rolling ball 33 rolls while being held by the ball receiving recesses 31a and 32a. Moreover, even when the main body 31 and retainer 32 are moved in the axial direction of the shaft 30, which is the first direction, each rolling ball 33 rolls while being held by the ball receiving recesses 31a and 32a. As a result, the main body 31 and retainer 32 can rotate smoothly relative to the shaft 30 with very little force and can also move in the axial direction of the shaft 30.

[0040] Furthermore, each retainer 32 has four pins 32b extending in the axial direction formed on the end face facing the main body 31. These pins 32b are formed to extend toward the main body 31 at positions facing each pin receiving groove 31b of the main body 31. By inserting each pin 32b of the retainer 32 into each pin receiving groove 31b of the main body 31, each retainer 32 is fitted into the main body 31. In this way, the main body 31 and the two retainers 32 are integrated.

[0041] Furthermore, the ball receiving recess 31a provided in the main body 31 and the ball receiving recess 32a provided in each retainer 32 each have inclined inner wall surfaces. These inner wall surfaces are inclined with respect to the axial direction of the shaft 30, and by sandwiching the rolling balls 33 from both sides, each rolling ball 33 is pressed toward the shaft 30. Therefore, the pressure with which each rolling ball 33 presses toward the shaft 30 changes depending on the fitting position of the retainer 32 toward the main body 31. That is, the pressing pressure increases when the retainer 32 is fitted deeply toward the main body 31, and decreases when it is fitted shallowly.

[0042] In this embodiment, by adjusting the fit of each retainer 32 to the main body 31, each rolling ball 33 makes contact with the shaft 30 without any play and can roll against the shaft 30 with light force. Alternatively, each retainer 32 may be bonded to the main body 31 once each rolling ball 33 is pressed against the shaft 30 with appropriate pressure.

[0043] On the other hand, each retainer 32, which is configured in a truncated cone shape, is provided with a rolling surface 32c on its outer circumference that can contact the surface of the fixing plate 12 and roll in a predetermined direction. This rolling surface 32c is a truncated cone surface provided around each retainer 32, centered on the central axis of the shaft 30, and is a tapered surface that narrows towards both ends of the shaft 30. The rolling surface 32c of the guide unit 18 is configured to contact a receiving recess 12a (Figure 3) formed in the fixing plate 12 and roll in a second direction perpendicular to the shaft 30.

[0044] Specifically, as shown in Figure 3, the bottom of the receiving recess 12a formed in the fixed plate 12 is provided with inclined surfaces 12c on both sides that are lower inward. These inclined surfaces 12c are inclined at an angle that matches the rolling surfaces 32c of the guide unit 18, and the guide unit 18 rolls with each rolling surface 32c and each inclined surface 12c in contact with each other. As a result, the guide unit 18 rolls precisely in a second direction perpendicular to the first direction relative to the fixed plate 12.

[0045] Thus, in this embodiment, the guide unit 18 guides the movement of the movable frame 14 relative to the fixed plate 12 in a first direction and a second direction perpendicular to the first direction. In contrast, movement of the movable frame 14 in the direction of rotation relative to the fixed plate 12 is suppressed by the guide unit 18. In this embodiment, the rolling surface 32c is provided on each retainer 32, but the rolling surface can also be provided on the retainer 32 and / or the main body 31. Furthermore, the shape of the rolling surface is not limited to a truncated cone; for example, a rail (not shown) extending in the rolling direction can be provided on the fixed plate 12, and the rolling surface can be configured to match the shape of this rail.

[0046] <Operation of the imaging device> Next, with reference to Figure 1, the operation of the imaging device 1 according to the first embodiment of the present invention will be described. First, by turning on the activation switch (not shown) for the shake correction function of the imaging device 1, the actuator 10 provided on the lens unit 2 is activated. The gyro 34 attached to the lens unit 2 detects vibrations in a predetermined frequency band moment by moment and outputs them to the controller 36. A lens position command signal is generated based on the angular velocity signal detected by the gyro 34. By moving the shake correction lens 16 moment by moment to the position commanded by this lens position command signal, the image focused on the image sensor surface 4a of the imaging device body 4 is stabilized.

[0047] The magnetic flux generated by each position-detecting magnet 28 (Figure 5) attached to the movable frame 14 is detected by each magnetic sensor 24 (Figure 2) attached to the shelf portion 19 of the fixed plate 12, and the position of the vibration-correcting lens 16 attached to the movable frame 14 is determined based on these detection signals. The controller 36 controls the current flowing through each drive coil 20 so that the vibration-correcting lens 16 moves to the position specified by the lens position command signal.

[0048] As a result, the movable frame 14, supported by the two support balls 17 and the guide unit 18, is moved in a plane perpendicular to the optical axis A by the thrust generated by the movable part drive mechanism (drive coil 20 and magnet assembly 22). Furthermore, since the movement of the movable frame 14 is guided in the first and second directions by the guide unit 18, the movable frame 14 is less likely to undergo rotational motion around the optical axis A. Therefore, rotational motion of the movable frame 14, which is unnecessary for image stabilization, is suppressed.

[0049] When the shake-correcting lens 16 reaches the position specified by the lens position command signal, the current flowing through each drive coil 20 is reduced to zero, and the driving force also becomes zero. Furthermore, if the moving frame 14 deviates from the position specified by the lens position command signal due to disturbances or changes in the lens position command signal, the controller 36 resumes current flowing through each drive coil 20. When current flows through each coil, a driving force is generated between the drive coil 20 and the drive magnets 22b and 22c positioned opposite each drive coil 20, and the moving frame 14 is returned to the position specified by the lens position command signal. As the above actions are repeated moment by moment, the shake-correcting lens 16 attached to the moving frame 14 moves in accordance with the lens position command signal. This stabilizes the image focused on the image sensor surface 4a of the imaging device body 4.

[0050] <Effects of the First Embodiment> According to the guide unit 18 of the first embodiment of the present invention, since four rolling balls 33 are held rotatably around the shaft 30, the movable frame 14 can slide smoothly in the axial direction of the shaft 30, which is the first direction, relative to the fixed plate 12. Furthermore, since a rolling surface 32c that can roll in a second direction is provided around the retainer 32 of the guide unit 18, the rolling surface 32c rolls around the shaft 30, allowing the movable frame 14 to slide smoothly in the second direction relative to the fixed plate 12. This enables the movement of the movable frame 14 to be guided with sufficient precision, and also allows the guide unit 18 to be miniaturized.

[0051] Furthermore, according to the guide unit 18 of this embodiment, the rolling surface 32c is a truncated conical surface centered on the central axis of the shaft 30, provided around each retainer 32. Therefore, the rolling surface 32c of each retainer 32 can roll accurately in the second direction, and the movable frame 14 can be accurately guided in the second direction.

[0052] Furthermore, according to the actuator 10 of this embodiment, since it is equipped with an attractive magnet (position detection magnet 28) that is attached to the movable frame 14 and attracts the shaft 30 of the guide unit 18, the guide unit 18 can be attached to the movable frame 14 without any play, and the guide unit 18 can guide the movable frame 14 in an accurate direction. In this embodiment of the actuator 10, the guide unit 18 is attached to the movable frame 14 and the rolling surface 32c of the guide unit 18 rolls in contact with the surface of the fixed plate 12, but the guide unit 18 can also be attached to the fixed plate 12. In this case, the rolling surface 32c of the guide unit 18 attached to the fixed plate 12 rolls in contact with the surface of the movable frame 14.

[0053] Furthermore, according to the actuator 10 of this embodiment, a position detection magnet 28, which functions as an adsorption magnet, is attached to the movable frame 14, and the magnetism of the adsorption magnet is detected by a magnetic sensor 24. As a result, the position of the movable frame 14 can be detected based on the detection signal of the magnetic sensor 24, and the adsorption magnet and the position detection magnet 28 can be used interchangeably.

[0054] Furthermore, according to the actuator 10 of this embodiment, there are three movable part drive mechanisms (drive coils 20 and magnet assemblies 22), and these three movable part drive mechanisms are oriented in the tangential direction of a circle centered on the optical axis A such that the directions of action of the driving force they generate are different from each other. In addition, the guide unit 18 is positioned between the movable part drive mechanisms, and the first direction of the guide unit 18 is oriented in a direction that approximates the tangential direction of a circle centered on the optical axis A, while the second direction is oriented in a direction that approximates the radial direction of a circle centered on the optical axis A. As a result, the movable frame 14 can be accurately translated, and unnecessary rotational movement of the movable frame 14 can be suppressed.

[0055] (Second Embodiment) Next, an imaging device according to a second embodiment of the present invention will be described with reference to Figures 8 to 10. The imaging device of this embodiment differs from the first embodiment described above in the configuration of the actuator and guide unit provided therein. Therefore, only the differences between this embodiment and the first embodiment will be described here, and similar configurations, operations, and effects will not be explained.

[0056] <Actuator Configuration> Figure 8 is a perspective view of the actuator provided in the imaging device of this embodiment. Figure 9 is an exploded perspective view of the actuator provided in the imaging device of this embodiment. Figure 10 is a perspective view of the guide unit provided in the actuator of this embodiment.

[0057] As shown in Figures 8 and 9, the actuator 110 has a fixed plate 112, which is a fixed part fixed inside the lens barrel 6 (Figure 1), and a movable frame 114, which is a movable part supported movably relative to the fixed plate 112. A vibration correction lens 16 is mounted in the center of the movable frame 114, and three support balls 117 (only one is shown in Figure 9) are arranged around it. Furthermore, a guide unit 118 is attached to the movable frame 114. As a result, the movable frame 114 is supported parallel to the fixed plate 112 by the three support balls 117 on a plane perpendicular to the optical axis A of the vibration correction lens 16, and its movement is guided by the guide unit 118. The actuator 110 in this embodiment is also equipped with a position sensor for detecting the position of the movable frame 114, but its illustration and description are omitted.

[0058] Next, as shown in Figure 9, the fixing plate 112, which is the fixed part, is a roughly circular, donut-shaped plate fixed inside the lens barrel 6. Two magnet assemblies 122 and three coil springs 124 are attached to this fixing plate 112 to pull the movable frame 114, which is supported by three support balls 117, towards the fixing plate 112. On the back side of the fixing plate 112 (opposite the movable frame 114), a back yoke 126 is attached to the back of each magnet assembly 122. Furthermore, a receiving recess 112a (Figure 8) is formed on the surface of the fixing plate 112, on which the guide unit 118 rolls.

[0059] The two magnet assemblies 122 are mounted perpendicular to each other on the fixed plate 112. Each magnet assembly 122 consists of two rectangular plate-shaped drive magnets 122a and 122b. A drive coil 120, mounted on the movable frame 114, is positioned opposite each magnet assembly 122 (Figure 8). The combination of the magnet assemblies 122 and the drive coils 120 each functions as a movable part drive mechanism that drives the movable frame 114 relative to the fixed plate 112.

[0060] Three coil springs 124 are attached at one end to the outer circumference of the fixed plate 112, spaced approximately 120 degrees apart with respect to the optical axis A. The other end of each coil spring 124 is attached to the outer circumference of the movable frame 114. Similarly, three support balls 117 are sandwiched between the fixed plate 112 and the movable frame 114, spaced approximately 120 degrees apart. As a result, the movable frame 114 is supported parallel to the fixed plate 112 by the support balls 117, and is pulled towards the fixed plate 112, allowing it to move in a plane perpendicular to the optical axis A.

[0061] On the other hand, the movable part, the movable frame 114, is a roughly circular, donut-shaped plate supported parallel to the fixed plate 112. Two drive coils 120 are mounted on this movable frame 114. Furthermore, a guide unit 118 is attached to the outer circumference of the movable frame 114.

[0062] The two drive coils 120 are fixed to the movable frame 114 so as to face the two magnet assemblies 122 provided on the fixed plate 112. That is, the two drive coils 120 are flattened coils wound in an oval shape, and are mounted to the movable frame 114 such that the major axes of the ovals are perpendicular to each other.

[0063] In this configuration, when current flows through the drive coil 120, an electromagnetic force acts on the drive coil 120, generating a driving force on the movable frame 114. Therefore, the combination of the magnet assembly 122 and the drive coil 120 positioned opposite it functions as a movable part drive mechanism that drives the movable frame 114 relative to the fixed plate 112. Accordingly, in this embodiment, the actuator 110 is equipped with two movable part drive mechanisms. Furthermore, since the magnetization boundary lines of each magnet assembly 122 are oriented tangentially to a circle centered on the optical axis A (Figure 9), the lines of action of the driving force generated by each movable part drive mechanism are oriented radially to the circle centered on the optical axis A.

[0064] In this embodiment, as shown in Figure 8, movable part drive mechanisms (magnet assembly 122 and drive coil 120) are provided vertically below and horizontally in the optical axis A, respectively. That is, in this embodiment, the two movable part drive mechanisms are positioned at a central angle of approximately 90 degrees with respect to the optical axis A, and the lines of action of the generated driving force are approximately perpendicular to each other. The guide unit 118 attached to the outer circumference of the movable frame 114 is positioned outside the approximately perpendicular angle formed by the two movable part drive mechanisms. In this embodiment, the guide unit 118 is positioned at a distance of approximately 135 degrees from each movable part drive mechanism, with respect to a central angle of approximately 135 degrees from each other with respect to the optical axis A.

[0065] <Guide Unit Configuration> Next, the configuration of the guide unit 118 will be described with reference to Figure 10. The configuration of the guide unit 118 according to the second embodiment of the present invention is generally the same as that of the guide unit 18 according to the first embodiment, but differs from the first embodiment in that a weight is attached to the main body. Figure 10 is a perspective view of the guide unit 118 according to the second embodiment of the present invention. The guide unit 118 of this embodiment can also be applied to the actuator 10 of the first embodiment of the present invention. Furthermore, the guide unit 18 of the first embodiment can also be applied to the actuator 110 of the second embodiment.

[0066] As shown in Figure 10, the guide unit 118 includes a shaft 130 attached to the movable frame 114, a main body component 131a arranged to surround the shaft 130, and retainers 132 attached to both sides of the main body component 131a. The structures of the shaft 130, main body component 131a, and retainer 132 are the same as those of the shaft 30, main body component 31, and retainer 32 of the first embodiment described above. Also the fact that there are four rolling balls (not shown in Figure 10) arranged between the main body component 131a and each retainer 132 is also the same as in the first embodiment.

[0067] In contrast, the guide unit 118 of this embodiment differs from the guide unit 18 of the first embodiment in that the main body portion 131 is composed of a main body part 131a and a metal weight 134 attached to its center. This weight 134 is attached in a recess formed on the outer circumference of the axial center of the main body part 131a. That is, the weight 134 is a metal member that extends in an arc shape so as to cover about half of the outer circumference of the main body part 131a. Here, the center of gravity of the main body part 131a and the retainer 132 attached to the shaft 130 is located on the central axis of the shaft 130. However, by attaching the metal weight 134 to a part of the outer circumference of the main body part 131a, the center of gravity of the main body portion 131 is located off-center from the central axis of the shaft 130.

[0068] In this embodiment, the main body 131 is equipped with a weight 134, so that the center of gravity of the main body 131 is located off-center from the central axis of the shaft 130, and the center of gravity of the main body 131 and the retainer 132 as a whole is also located off-center from the central axis. In contrast, as a modification, the retainer 132 may be configured such that its center of gravity is located off-center from the central axis of the shaft 130, and the present invention may be configured such that the center of gravity of the main body 131 and the retainer 132 as a whole is located off-center from the central axis. Alternatively, the main body 131 and the retainer 132 may be configured such that their centers of gravity are located off-center from the central axis of the shaft 130.

[0069] In this embodiment, as shown in Figure 8, the shaft 130 of the guide unit 118 is oriented in the tangential direction of a circle centered on the optical axis A, which is the first direction. The main body 131 and retainer 132 attached to the shaft 130 roll in the radial direction of a circle centered on the optical axis A, which is the second direction. In this way, in this embodiment, the main body 131 and retainer 132 slide in the direction of the shaft 130 and roll around the shaft 130, thereby guiding the movable frame 114 in the first and second directions.

[0070] As described above, in this embodiment, the center of gravity of the entire body 131 and retainer 132 is located off-center from the central axis. As a result, as shown in Figure 8, when the guide unit 118 is attached to the actuator 110 and used, a force acts on the guide unit 118 that attempts to rotate it so that its center of gravity is at its lowest position due to gravity acting on it. For example, if the weight 134 of the guide unit 118 is in the position shown in Figure 8, a rotational force acts on the guide unit 118 in the direction indicated by arrow T in Figure 8 so that its center of gravity is moved to its lowest position.

[0071] Here, the guide unit 118 rolls with the rolling surfaces 132a of each retainer 132 in contact with the receiving recesses 112a of the fixed plate 112. As a result, the rotation of the guide unit 118 in the direction of arrow T acts to pull the movable frame 114 upwards in the direction shown in the upper right of Figure 8 relative to the fixed plate 112. This cancels out a portion of the gravitational force acting on the movable frame 114, thereby reducing the driving force that the movable part drive mechanism (drive coil 120 and magnet assembly 122) would otherwise have to generate against gravity.

[0072] <Effects of the second embodiment> According to the guide unit 118 of the second embodiment of the present invention, since the center of gravity of the main body 131 is off-center from the central axis of the shaft 130, gravity causes a rotational force to act on the guide unit 118. By causing this rotational force to act in a direction that pulls up the movable frame 114, at least a portion of the driving force by the movable part drive mechanism (drive coil 120 and magnet assembly 122) necessary to hold the movable frame 114 in a predetermined position against gravity can be offset. As a result, the power consumed by the movable part drive mechanism can be reduced.

[0073] Furthermore, according to the actuator 110 of this embodiment, the lines of action of the driving forces generated by the two movable part drive mechanisms are arranged to be approximately perpendicular to each other, and the guide unit 118 is positioned outside the approximately perpendicular line formed by the two movable part drive mechanisms. The first direction of the guide unit is directed in the tangential direction of the circle centered on the optical axis, and the second direction is directed in the radial direction of the circle centered on the optical axis. Therefore, by providing only two movable part drive mechanisms, the movable frame 114 can be translated and moved to any position in a plane perpendicular to the optical axis A. In addition, rotational movement of the movable frame 114 is suppressed by the guide unit 118.

[0074] (Modified version of the second embodiment) Next, a modified example of the guide unit according to the second embodiment of the present invention will be described with reference to Figure 11. Note that this modified guide unit can also be applied to the actuator 10 of the first embodiment of the present invention. Figure 11 is an exploded perspective view of the guide unit according to this modification.

[0075] As shown in Figure 11, the modified guide unit 218 includes a shaft 230 attached to a movable frame, a main body 231 arranged to surround the shaft 230, and retainers 232 attached to both sides of the main body 231. Furthermore, four rolling balls 233 are arranged at each end of the main body 231 (only one side is shown in Figure 11) to surround the shaft 230. The rolling balls 233 are metal spheres and are held between the main body 231 and each retainer 232 so that they can roll around the shaft 230.

[0076] In this modified example, the entire main body 231 is made of metal, and the retainers 232 fitted to both sides of it are made of resin. The configuration of each retainer 232 is substantially the same as in the first and second embodiments, with a rolling surface 232a formed at one end and the other end fitted to the main body 231 to hold the rolling balls 233.

[0077] In this modified example, the metal main body 231 is configured to surround the shaft 230, and its central portion in the axial direction is cut out. That is, the cut-out portion of the main body 231 has a roughly semicircular cross-section. As a result, the center of gravity of the main body 231 is located off-center from the central axis of the shaft 230. This also results in the center of gravity of the entire main body 231 and retainer 232 being off-center from the central axis, allowing the guide unit 218 to generate rotational force due to its own weight when attached to the movable frame.

[0078] According to this modified example, the main body 231 is made of metal and integrally formed, and the center of gravity of the main body 231 is off-center from the central axis of the shaft 230, so a guide unit 218 capable of generating rotational force can be constructed with a simple structure.

[0079] (Modification 2 of the second embodiment) Next, a second modified example of the guide unit according to the second embodiment of the present invention will be described with reference to Figure 12. Note that this modified guide unit can also be applied to the actuator 10 of the first embodiment of the present invention. Figure 12 is an exploded perspective view of the guide unit according to this modification.

[0080] As shown in Figure 12, the modified guide unit 318 includes a shaft 330 attached to a movable frame, a main body 331 arranged to surround the shaft 330, and retainers 332 attached to both sides of the main body 331. Furthermore, four rolling balls 333 are arranged at each end of the main body 331, surrounding the shaft 330. The rolling balls 333 are metal spheres and are held between the main body 231 and each retainer 332 so that they can roll around the shaft 330.

[0081] In this modified example, the entire main body 331 is made of metal, and the retainers 332 fitted to both sides of it are cylindrical resin components. In this modified example, the diameter of each retainer 332 is smaller than the diameter of the main body 331, and each retainer 332 is inserted into a cylindrical recess 331a provided at both ends of the main body 331 and fitted to the main body 331. As a result, each rolling ball 333 is held between the main body 331 and each retainer 332.

[0082] Furthermore, in this modified example, the metal main body 331 is configured to surround the shaft 330, and its central portion in the axial direction is cut out, resulting in a roughly semicircular cross-section. As a result, the center of gravity of the main body 331 is located off-center from the central axis of the shaft 330. This also results in the center of gravity of the entire main body 331 and retainer 332 being off-center from the central axis, allowing the guide unit 318 to generate rotational force due to its own weight when attached to the movable frame.

[0083] According to this modified example, the main body 331 is made of metal and formed as a single unit, and the center of gravity of the main body 331 is off-center from the central axis of the shaft 330, so a guide unit 318 capable of generating rotational force can be constructed with a simple structure.

[0084] Furthermore, in this modified example, both ends of the main body 331 are each formed into truncated conical surfaces that surround the recess 331a, and these truncated conical surfaces constitute the rolling surfaces 331b (only one side is shown in Figure 12) that contact and roll against the fixed plate. In this modified example, since the rolling surfaces 331b on both sides are provided on the main body 331 which is integrally formed, the central axes of the two rolling surfaces 331b can be precisely aligned.

[0085] (summary) A guide unit according to Embodiment 1 of the present invention is a guide unit that guides the movement of a movable part relative to a fixed part in two directions, and comprises a shaft attached to one of the fixed part or the movable part so as to extend in a first direction, a main body arranged so as to surround the shaft, three or more rolling balls arranged at each end of the main body so as to surround the shaft, and retainers attached to both sides of the main body, which hold the rolling balls in the main body so that each rolling ball can roll around the shaft, and the main body and / or retainers are provided with rolling surfaces that can roll in a second direction in contact with the other surface of the fixed part or the movable part.

[0086] In this configuration, Embodiment 1, since three or more rolling balls are held rotatably around the shaft, the movable part can slide smoothly relative to the fixed part in the first direction, which is the axial direction of the shaft. Furthermore, since rolling surfaces that can roll in a second direction are provided around the main body and / or retainer, the movable part can slide smoothly relative to the fixed part in the second direction as the rolling surfaces roll around the shaft. This allows the movement of the movable part to be guided with sufficient precision, and the guide unit can be miniaturized.

[0087] Furthermore, in the guide unit according to embodiment 2 of the present invention, in embodiment 1, the rolling surface is a truncated conical surface provided around each retainer, centered on the central axis of the shaft. With embodiment 2 configured in this way, since the rolling surface is a truncated conical surface, each retainer can be accurately rolled in the second direction, and the movable part can be accurately guided.

[0088] Furthermore, in the guide unit according to embodiment 3 of the present invention, in embodiment 1 or 2, the center of gravity of the main body and / or retainer is offset from the central axis of the shaft. With embodiment 3 configured in this way, rotational force can be generated by the weight of the main body and / or retainer, and at least a portion of the gravitational force acting on the movable part can be offset.

[0089] Furthermore, in any one of embodiments 1 to 3, the guide unit according to embodiment 4 of the present invention has a main body made of metal, and the center of gravity of the main body is offset from the central axis of the shaft. With embodiment 4 configured in this way, a main body with a center of gravity offset from the central axis of the shaft can be constructed with a simple structure.

[0090] Furthermore, an actuator according to aspect 5 of the present invention is an actuator for moving a lens or lens group in a plane perpendicular to the optical axis, and is characterized by comprising: a fixed part; a movable part supported on the fixed part so as to be movable in a plane perpendicular to the optical axis; a movable part drive mechanism for moving the movable part on the fixed part in a plane perpendicular to the optical axis; and one of the guide units of aspects 1 to 4 for guiding the movement of the movable part on the fixed part in a first direction and a second direction perpendicular to the first direction.

[0091] In this configuration, embodiment 5, a guide unit is provided to guide the movement of the movable part relative to the fixed part in a first direction and a second direction perpendicular to the first direction. As a result, the rotational movement of the movable part is suppressed by the movable part drive mechanism, and the movable part can be accurately translated.

[0092] Furthermore, the actuator according to embodiment 6 of the present invention, in embodiment 5, further includes an adsorption magnet attached to either the fixed part or the movable part to attract the shaft of the guide unit. With embodiment 6 configured in this way, the shaft of the guide unit can be supported without any play because it has an adsorption magnet.

[0093] Furthermore, in embodiment 7 of the present invention, the actuator in embodiment 5 or 6 has an attraction magnet attached to a movable part and has a magnetization boundary line extending in a plane perpendicular to the optical axis, and further has a magnetic sensor for detecting the magnetism of the attraction magnet. With embodiment 7 configured in this way, the attraction magnet can also be used as a position detection magnet for position detection, and position detection can be performed without providing a separate position detection magnet.

[0094] Furthermore, in any one of embodiments 5 to 7, the actuator according to embodiment 8 of the present invention is provided with two movable part drive mechanisms, which are arranged such that the lines of action of the driving force they generate are substantially perpendicular to each other, and the guide unit is positioned outside the substantially perpendicular line formed by the two movable part drive mechanisms, and the first direction of the guide unit is directed in the tangential direction of the circle centered on the optical axis, while the second direction is directed in the radial direction of the circle centered on the optical axis.

[0095] According to embodiment 8 configured in this way, the movable part can be driven by two movable part drive mechanisms, and the guide unit can guide the movable part in the first and second directions, thereby suppressing rotational movement of the movable part.

[0096] Furthermore, in any one of embodiments 5 to 7, the actuator according to embodiment 9 of the present invention is provided with three movable part drive mechanisms, these three movable part drive mechanisms are arranged such that the directions of the lines of action of the driving force they generate are different from each other, and the guide unit is positioned between the movable part drive mechanisms. According to embodiment 9 configured in this way, the guide unit can guide the movable part in a first direction and a second direction, thereby suppressing the rotational movement of the movable part.

[0097] Furthermore, the lens unit according to embodiment 10 of the present invention is a lens unit used by being attached to an imaging device, and is characterized by having a lens barrel and an actuator according to any one of embodiments 5 to 9 for moving a lens or lens group arranged inside the lens barrel in a plane perpendicular to the optical axis.

[0098] Furthermore, the imaging device according to aspect 11 of the present invention is an imaging device for capturing video or still images, and is characterized by having a lens unit as described in aspect 10 and an imaging device body to which the lens unit is attached.

[0099] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0100] 1. Imaging device 2 Lens Units 4. Imaging device main unit 4a Image sensor surface 6 Lens barrel 8 lenses 10 Actuators 12 Fixed plate (fixed part) 12a Receiving recess 12b Ball catcher 12c slope 14. Movable frame (movable part) 14a Guide unit support section 14b Ball catcher 16 Image stabilization lens 17 Support ball 18 Guide Units 19 Shelf 20 Drive coils 22 Magnet Assembly 22a York 22b Drive magnet 22c drive magnet 24 Magnetic Sensors 26 Back yoke 28. Magnets for position detection (magnets for attraction) 30 shafts 31 Main body 31a Ball receiving recess 31b Pin receiving groove 32 retainers 32a Ball receiving recess 32b pin 32c Rolling surface 33 Rolling Ball 34 Gyro 36 Controllers 110 Actuator 112 Fixed plate (fixed part) 114 Movable frame (movable part) 117 Support ball 118 Guide Unit 120 Drive coil 112a Receiving recess 122 Magnet Assembly 122a Drive Magnet 122b Drive magnet 124 Coil spring 126 Back Yoke 130 shaft 131 Main body 131a Main body parts 132 Retainer 132a Rolling surface 134 weights 218 Guide Unit 230 shaft 231 Main body 232 Retainer 232a Rolling surface 233 Rolling Ball 318 Guide Unit 330 shaft 331 Main body 331a Recess 331b Rolling surface 332 Retainer 333 Rolling Ball

Claims

1. A guide unit that guides the movement of a movable part relative to a fixed part in two directions, A shaft is attached to either the fixed or movable part so as to extend in a first direction, The main body is arranged to surround this shaft, At both ends of this main body, there are three or more rolling balls arranged around the shaft, A retainer is attached to each side of the main body, and holds the rolling balls to the main body so that each rolling ball can roll around the shaft. It has, A guide unit characterized in that a rolling surface is provided around the main body and / or the retainer, which can roll in a second direction and contact the other surface of the fixed part or the movable part.

2. The guide unit according to claim 1, wherein the rolling surface is a truncated conical surface provided around each of the retainers, centered on the central axis of the shaft.

3. The guide unit according to claim 1, wherein the main body and / or the retainer have their center of gravity offset from the central axis of the shaft.

4. The guide unit according to claim 3, wherein the main body is made of metal, and the center of gravity of the main body is offset from the central axis of the shaft.

5. An actuator for moving a lens or lens group in a plane perpendicular to the optical axis, The fixing part, A movable part is supported on the fixed part so as to be movable in a plane perpendicular to the optical axis, A movable part drive mechanism moves this movable part in a plane perpendicular to the optical axis relative to the fixed part, A guide unit according to claim 1, which guides the movement of the movable part relative to the fixed part in the first direction and in a second direction perpendicular to the first direction, An actuator characterized by having the following features.

6. Furthermore, the actuator according to claim 5, having a magnet for attracting the shaft of the guide unit, which is attached to either the fixed part or the movable part.

7. The actuator according to claim 6, wherein the above-mentioned magnet for attraction is attached to the above-mentioned movable part and has a magnetization boundary line extending in a plane perpendicular to the optical axis, and further comprises a magnetic sensor for detecting the magnetism of the above-mentioned magnet for attraction.

8. The actuator according to claim 5, wherein the actuator is provided with two of the above-mentioned movable part drive mechanisms, which are arranged such that the lines of action of the driving force they generate are substantially perpendicular to each other, and the guide unit is positioned outside the substantially perpendicular line formed by the two movable part drive mechanisms, and the first direction of the guide unit is directed in the tangential direction of a circle centered on the optical axis, and the second direction is directed in the radial direction of a circle centered on the optical axis.

9. The actuator according to claim 5, wherein the above-mentioned movable part drive mechanism is provided in three, and these three movable part drive mechanisms are arranged such that the directions of the lines of action of the driving force they generate are different from each other, and the guide unit is arranged between the above-mentioned movable part drive mechanisms.

10. A lens unit used by attaching it to an imaging device, Lens barrel and An actuator according to any one of claims 5 to 9 for moving a lens or lens group arranged inside the lens barrel in a plane perpendicular to the optical axis, A lens unit characterized by having the following features.

11. An imaging device for capturing video or still images, The lens unit according to claim 10, The main body of the imaging device to which this lens unit is attached, An imaging device characterized by having the following features.

Images