JP2008070613A - Actuator, lens unit equipped with the same, and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator capable of locking a movable part without providing a special actuator for driving a member such as a lock ring. <P>SOLUTION: The actuator (10) for preventing image blur by translationally moving an imaging lens (16) includes: a fixed part (12); the movable part (14) to which the imaging lens is attached; a movable part supporting means (18) movably supporting the movable part relative to the fixed part; driving means (20 and 22) for translationally moving and rotationally moving the movable part relative to the fixed part; a plurality of engaging parts(17) provided to the movable part; and a plurality of elastic engaging part receiving parts (15) provided to the fixed part respectively correspondingly to the engaging parts, elastically deformed by the respective engaging parts in the middle of rotational moving of the movable part to a predetermined locking position, and holding the movable part at the locking position since elastically deformed amount is reduced when the movable part reaches the locking position. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an actuator, a lens unit including the actuator, and a camera, and more particularly to an actuator that translates an imaging lens in a plane perpendicular to the optical axis thereof to prevent image blur, and a lens unit including the actuator. , About the camera.

  Japanese Patent No. 3397536 (Patent Document 1) describes a correction optical device. The correction optical device includes a correction lens that decenters the optical axis, and a lock ring that locks the correction lens. The lock ring has an annular shape surrounding the correction lens, and a cam portion that engages with the frame of the correction lens is formed on the inner periphery thereof. In this correction optical device, when the correction by the correction optical device is not performed, the lock ring surrounding the correction lens is rotated so that the cam portion formed on the inner periphery thereof and the outer peripheral portion of the frame of the correction lens are arranged. The correction lens is locked by engaging.

Japanese Patent No. 3397536

  However, in the correction optical device described in Japanese Patent No. 3397536, it is necessary to rotate the lock ring in order to lock the correction lens. For this reason, the lock is separated separately from the actuator for driving the correction lens. There is a problem that an actuator must be provided. Furthermore, in order to lock the correction lens by engaging the lock ring cam with the correction lens frame, it is necessary to hold the correction lens against the force of pressing the cam. There is a problem that the lens support mechanism must be constructed more robustly than necessary.

  Accordingly, an object of the present invention is to provide an actuator capable of locking a movable portion without providing a special actuator for driving a member such as a lock ring, and a lens unit and a camera including the actuator. It is said.

  In order to solve the above-described problems, the present invention provides an actuator for translating an imaging lens in a plane orthogonal to the optical axis thereof to prevent image blur, and includes a fixing unit and an imaging lens. An attached movable part, a movable part support means for supporting the movable part so that the movable part can be moved on a plane parallel to the fixed part, and for moving the movable part in translation and rotation with respect to the fixed part. A driving means, a plurality of engaging portions provided in the movable portion, and a fixed portion corresponding to each of the engaging portions, and each engaging portion being rotated to a predetermined locking position. And a plurality of elastic engaging portion receiving portions that are elastically deformed by the joint portion and reduce the amount of elastic deformation when the movable portion reaches the locking position and hold the movable portion at the locking position.

  In the present invention configured as described above, the movable part to which the imaging lens is attached is supported by the movable part support means so as to be movable on a plane parallel to the fixed part. The movable part is moved with respect to the fixed part by the driving means to prevent image shake. When the movable part is moved to a predetermined locking position, the movable part is rotated. The plurality of engaging portions provided in the movable portion elastically deform the plurality of elastic engaging portion receiving portions while the movable portion is rotationally moved to the locking position. When the movable portion reaches the locking position, the amount of elastic deformation of each elastic engagement portion receiving portion decreases, and the elastic engagement portion receiving portion holds the movable portion at the locking position.

  According to the present invention configured as described above, the movable part itself to which the imaging lens is attached is rotated and moved to the locking position, and is locked. The movable part can be locked without providing a simple actuator.

  In the present invention, preferably, each engaging portion is formed in the movable portion so as to extend substantially radially with respect to the optical axis of the imaging lens, and each elastic engaging portion receiving portion is inward in the radial direction. When the movable part is moved to the locking position, it is pressed by the engaging part and elastically deformed radially outward.

  In the present invention configured as described above, each engaging portion presses each elastic engaging portion receiving portion and elastically deforms outward in the radial direction when the movable portion is moved to the locking position. When the movable portion reaches the locking position, the amount of elastic deformation of the elastic engagement portion receiving portion decreases, and the movable portion is held at the locking position.

  In the present invention, preferably, each elastic engagement portion receiving portion has two inclined surfaces on which the engaging portions slide, and the inclined surface on the side pressed when the movable portion is released from the locking position, It is formed steeper than the slope on the side that is pressed when the movable part is moved to the locking position.

  In the present invention configured as described above, when the movable portion is moved to the locking position, each engaging portion is elastically deformed by pressing a gentle slope of each elastic engaging portion receiving portion, When the movable part is released from the locking position, the steep slope of each elastic engagement part receiving part is pressed and elastically deformed.

  According to the present invention configured as described above, when releasing the movable portion from the locking position, it is necessary to press the steep slope of the elastic engagement portion receiving portion. A large force is required to deform. Thereby, it is possible to prevent the movable part from being accidentally released from the locking position due to an impact force or the like.

  In the present invention, preferably, it further includes a rotation urging means for applying a rotational force to the movable portion at the locking position, and each rotational engagement force causes each of the engagement portions to move to each elastic engagement portion at the locking position. Pressed against the receiving part.

  According to the present invention configured as described above, the movable portion in the locking position is given a rotational force by the rotation urging means, and each engagement portion is pressed against each elastic engagement portion receiving portion, so that each elastic portion Since the engaging portion receiving portion is slightly elastically deformed, the movable portion can be held in the locking position without play.

The lens unit of the present invention includes a lens barrel, a plurality of imaging lenses housed in the lens barrel, and an actuator of the present invention in which a part of these imaging lenses is attached to a movable part. It is characterized by having.
Furthermore, the camera of the present invention has a camera body and the lens unit of the present invention.

  According to the actuator of the present invention, and the lens unit and camera including the actuator, the movable part can be locked without providing a special member such as a lock ring and an actuator for driving the member.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
First, a camera according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a camera according to an embodiment of the present invention.

  As shown in FIG. 1, a camera 1 according to an embodiment of the present invention includes a lens unit 2 and a camera body 4. The lens unit 2 includes a lens barrel 6, a plurality of imaging lenses 8 disposed in the lens barrel, and an actuator that moves an image blur correction lens 16 of the imaging lenses within a predetermined plane. 10 and gyros 34a and 34b (only 34a is shown in FIG. 1) as vibration detecting means for detecting vibration of the lens barrel 6.

The lens unit 2 is attached to the camera body 4 and configured to form incident light on the film surface F.
The generally cylindrical lens barrel 6 holds a plurality of imaging lenses 8 therein, and allows focus adjustment by moving some imaging lenses 8.

  The camera 1 according to the embodiment of the present invention detects vibrations by the gyros 34 a and 34 b, operates the actuator 10 based on the detected vibrations to move the image blur correction lens 16, and moves the film surface in the camera body 4. The image focused on F is stabilized. In the present embodiment, piezoelectric vibration gyros are used as the gyros 34a and 34b. In the present embodiment, the image blur correction lens 16 is constituted by a single lens, but the lens for stabilizing the image may be a plurality of lens groups.

  Next, the configuration of the actuator 10 will be described with reference to FIGS. FIG. 2 is a side sectional view of the actuator 10 in which the moving frame is in the position of image blur prevention control. 3 is a rear view of the actuator 10 viewed from the camera body 4 side, and FIG. 4 is a rear view of the actuator 10 showing a state in which the fixed frame is removed. FIG. 5 is a front view of the fixed frame as viewed from the front end side of the lens unit 2. Moreover, Fig.6 (a) is side surface sectional drawing which follows the VI-VI line of FIG. FIG. 6B is a perspective view showing a magnetized state of the driving magnet.

  As shown in FIGS. 2 to 5, the actuator 10 has a housing 11 fixed in the lens barrel 6, a fixed frame 12 that is a fixed portion attached to the housing 11, and moves relative to the fixed frame 12. The movable frame 14 is a movable part supported so as to be movable, and three steel balls 18 (FIG. 4) are movable part supporting means for supporting the movable frame 14. Further, the actuator 10 is attached at positions corresponding to the three drive coils 20a, 20b, and 20c (FIG. 5) attached to the fixed frame 12 and the drive coils 20a, 20b, and 20c on the moving frame 14, respectively. And three drive magnets 22a, 22b, 22c (FIG. 4).

  Further, as shown in FIG. 6A, the actuator 10 is provided with an attracting member attached to the fixed frame 12 so that the moving frame 14 is attracted to the fixed frame 12 by the magnetic force of each driving magnet 22a, 22b, 22c. A yoke 26 and a back yoke 28 attached to the back side of the drive magnet so as to effectively direct the magnetic force of the drive magnet toward the fixed frame 12 are included. The driving coils 20a, 20b, and 20c, and the three driving magnets 22a, 22b, and 22c attached to the corresponding positions cause the moving frame 14 to translate and rotate with respect to the fixed frame 12. The drive means which can be moved is comprised.

  Further, as shown in FIGS. 5 and 6A, Hall elements 24a, 24b, and 24c, which are magnetic sensors, are arranged inside the windings of the drive coils 20a, 20b, and 20c (see FIG. 5). 6 (a) shows only 24a). Each Hall element 24a, 24b, 24c detects the magnetism of each driving magnet 22a, 22b, 22c arranged so as to face each other, and detects the position of the moving frame 14 with respect to the fixed frame 12. It is configured. These Hall elements 24a, 24b, 24c and the drive magnets 22a, 22b, 22c constitute position detecting means.

  Further, as shown in FIG. 1, the actuator 10 includes each drive coil 20a based on the vibration detected by the gyros 34a and 34b and the positional information of the moving frame 14 detected by the Hall elements 24a, 24b and 24c. , 20b, 20c has a controller 36 which is a control means for controlling the current to flow. Further, the controller 36 has a built-in locking position moving means 37 for moving the moving frame 14 to the locking position that is the target position.

  The actuator 10 moves the moving frame 14 with respect to the fixed frame 12 fixed to the lens barrel 6 in a plane parallel to the film surface F, and thereby the image blur correction lens attached to the moving frame 14. 16 is moved so that the image formed on the film surface F is not disturbed even if the lens barrel 6 vibrates.

As shown in FIGS. 2 and 4, the housing 11 has a generally donut plate shape with an edge on the outer periphery.
As shown in FIGS. 3 and 5, the fixed frame 12 has a generally donut plate shape, and three driving coils 20a, 20b, and 20c are disposed thereon. As shown in FIG. 5, the centers of these three driving coils 20 a, 20 b, and 20 c are arranged on a circumference centered on the optical axis of the lens unit 2. In the present embodiment, the drive coil 20a is disposed vertically above the optical axis, and the drive coils 20b and 20c are disposed with a central angle of 120 ° from the drive coil 20a. That is, the driving coils 20a, 20b, and 20c are arranged at equal intervals on a circumference centered on the optical axis. The driving coils 20a, 20b, and 20c are arranged such that their windings are wound in a rectangular shape with rounded corners, and the center line of the rectangle coincides with the radial direction of the circumference.

  Next, as shown in FIGS. 2 and 4, the moving frame 14 has a generally donut plate shape and is disposed so as to be surrounded by the edge of the housing 11 in parallel with the fixed frame 12. An image blur correction lens 16 is attached to the central opening of the moving frame 14. In addition, rectangular driving magnets 22a, 22b, and 22c are embedded at positions on the circumference of the moving frame 14 corresponding to the driving coils 20a, 20b, and 20c, respectively. In the present specification, the position corresponding to the driving coil means a position where the influence of the magnetic field formed by the driving coil is substantially reached. In addition, rectangular back yokes 28 are attached to the back side of the drive magnet, that is, on the opposite side of each drive coil, so that the magnetic flux of each drive magnet is efficiently directed toward the fixed frame 12. It has been.

  In addition, rectangular suction yokes 26 are attached to the back side of each driving coil of the fixed frame 12, that is, on the opposite side of the moving frame 14. The moving frame 14 is attracted to the fixed frame 12 by the magnetic force exerted by each of the driving magnets 22a, 22b, and 22c on the attracting yoke 26 attached thereto. In the present embodiment, the fixed frame 12 is made of a nonmagnetic material so that the magnetic lines of force of the drive magnet can efficiently reach the attraction yoke 26.

Next, the support mechanism of the moving frame 14 by the steel balls 18 will be described with reference to FIGS.
As shown in FIG. 2, the three steel balls 18 are respectively disposed between the fixed frame 12 and the moving frame 14. Further, as shown in FIG. 5, the three steel balls 18 are arranged at intervals of a central angle of 120 °, and the steel balls 18 are arranged so as to be positioned between the drive coils. Yes. Each steel ball 18 is disposed between raised portions 12 a and 14 c formed at positions corresponding to the steel balls 18 of the fixed frame 12 and the moving frame 14, respectively. The moving frame 14 is attracted to the fixed frame 12 by the driving magnet 22, and each steel ball 18 is sandwiched between the fixed frame 12 and the moving frame 14. As a result, the moving frame 14 is supported on a plane parallel to the fixed frame 12, and the rolling motion of the moving frame 14 with respect to the fixed frame 12 in any direction is allowed by rolling while the steel balls 18 are sandwiched. Is done.

  In this embodiment, a steel sphere is used as the steel ball 18, but the steel ball 18 is not necessarily a sphere. That is, if the portion that contacts the fixed frame 12 and the moving frame 14 during the operation of the actuator 10 has a substantially spherical shape, the steel ball 18 can be used. In addition, in this specification, such a form is called a spherical body.

  Next, the magnetic force exerted by the drive magnet will be described with reference to FIG. The drive magnets 22a, 22b, 22c, the back yoke 28, and the attracting yoke 26 each have a rectangular shape, and are arranged so that the long sides and the short sides overlap each other. The driving coils 20a, 20b, and 20c are arranged such that their sides are parallel to the long and short sides of the rectangular back yoke 28, respectively. Further, each drive magnet is oriented such that the magnetization boundary line C, which is the boundary line between the magnetic poles, coincides with the radial direction of the circumference where each drive magnet is disposed.

  Thereby, the drive magnet 22a, the back yoke 28, and the attracting yoke 26 constitute a magnetic circuit, and magnetic lines of force indicated by arrows in FIG. 6A are formed. When a current flows through the corresponding driving coil 20a, the driving magnet 22a receives a circumferential tangential driving force. For the other driving coils 20b and 20c, corresponding driving magnets 22b and 22c, a back yoke 28, and an attracting yoke 26 are arranged in the same positional relationship.

  In this specification, the magnetization boundary line C refers to the boundary line of the magnetized magnetic poles when both ends of the drive magnet are magnetized so as to be S pole and N pole, respectively. Shall. Accordingly, in the present embodiment, the magnetization boundary line C is positioned so as to pass through the midpoint of each long side of the rectangular driving magnet. As shown in FIG. 6B, the polarity of the driving magnet 22a also changes in the thickness direction. In FIG. 6B, the lower left corner is the S pole, the lower right corner is the N pole, The upper left is the N pole and the upper right is the S pole.

  Next, with reference to FIG.6 and FIG.7, the drive force which each drive magnet receives is demonstrated. FIG. 7A is a graph showing the relationship between the relative position of the driving coil and the driving magnet and the driving force received by the driving magnet, and FIGS. 7B to 7E show b in the graph. The relative positions of the driving coil and the driving magnet at points e to e are shown.

  First, as shown in FIG. 6A, the right half, which is the first magnet portion 22a1, of the driving magnet 22a is connected to the right end portion, which is the first winding portion 20a1, of the driving coil 20a. ) Exerts magnetic field lines from the top to the bottom. Similarly, the left half portion that is the second magnet portion 22a2 of the driving magnet 22a has a magnetic field line that extends from below to above in FIG. 6A on the left end portion that is the second winding portion 20a2 of the driving coil 20a. Effect.

  On the other hand, when a current in the direction indicated by the arrow in FIG. 7B flows through the driving coil 20a, a current flows from the back of FIG. 6A toward the front side in the first winding portion 20a1 of the driving coil 20a. Current flows through the second winding portion 20a2 from the near side of FIG. 6A toward the back. When such a current flows in the magnetic field formed by the driving magnet 22a, a driving force for moving the driving magnet 22a in the right direction in FIG. 6A is generated.

  As shown in FIG. 7A, this driving force is obtained when the driving magnet 22a and the driving coil 20a are in the positional relationship shown in FIG. 7B, that is, the magnetization boundary line C of the driving magnet 22a. Is maximized when it is located at the center of the drive coil 20a. Further, the driving force decreases as the driving magnet 22a shifts to the right or left from the maximum position. Further, when the driving magnet 22a is moved rightward to the position shown in FIG. 7C (point c in FIG. 7A), the driving force becomes zero. When the driving magnet 22a is further moved to reach the position shown in FIG. 7D (point d in FIG. 7A), the direction of the driving force is reversed, and the driving magnet 22a is driven in the left direction. To receive. Thus, in the state where the driving force is reversed, the driving magnet 22a receives only the driving force generated between the second magnet portion 22a2 and the first winding portion 20a1 of the driving coil 20a. Therefore, the maximum value of the driving force in the region where the driving force is reversed is smaller than the driving force in the state of FIG.

  On the other hand, also when the driving magnet 22a is moved leftward, the driving force decreases and becomes zero at the position shown in FIG. 7E (point e in FIG. 7A). Further, when the driving magnet 22a is further moved leftward, the direction of the driving force is reversed, and the driving magnet 22a receives the leftward driving force.

  The driving force described above is for the case where the clockwise current in FIG. 7B flows through the driving coil 20a. When the counterclockwise current flows through the driving coil 20a, the driving force is as follows. All the directions are reversed. That is, when a counterclockwise current flows through the driving coil 20a, a leftward driving force is generated in the region from the point e to the point c in FIG. In the region on the right side of the point c, a right driving force is generated. In the above description, the driving force generated between the driving coil 20a and the driving magnet 22a has been described. However, the driving force generated between the other two sets of driving coils and the driving magnet is exactly the same. is there.

  Further, in the actuator 10 of the camera 1 according to the present embodiment, the first winding portion of the driving coil and the first magnet portion of the driving magnet, and the second winding portion and the second magnet portion face each other, and sufficient driving is performed. Image blur prevention control is executed in a normal operation region where a force is generated. Furthermore, the locking position at which the moving frame 14 is locked is set outside the normal operation region. At this locking position, the second winding portion of the driving coil and the first magnet portion of the driving magnet are located. opposite.

Next, the position detection of the moving frame 14 will be described with reference to FIGS.
8 and 9 are diagrams illustrating the relationship between the movement of the driving magnet 22a and the signal output from the Hall element 24a. As shown in FIG. 8, when the sensitivity center point S of the Hall element 24a is located on the magnetization boundary line C of the driving magnet 22a, the output signal from the Hall element 24a is zero. When the driving magnet 22a is moved together with the moving frame 14, and the sensitivity center point of the Hall element 24a deviates from the magnetization boundary line of the driving magnet 22a, the output signal of the Hall element 24a changes. As shown in FIG. 8, when the driving magnet 22a moves in the direction orthogonal to the magnetization boundary line C, that is, in the X-axis direction, the Hall element 24a generates a sinusoidal signal. Therefore, when the amount of movement is small, the Hall element 24a outputs a signal that is substantially proportional to the distance of movement of the driving magnet 22a. In the present embodiment, when the moving distance of the driving magnet 22a is within about 3% of the length of the long side of the driving magnet 22a, the signal output from the Hall element 24a is the sensitivity center of the Hall element 24a. This is approximately proportional to the distance between the point S and the magnetization boundary line C of the driving magnet 22a. In the present embodiment, the actuator 10 operates within a range in which the output of each Hall element is substantially proportional to the distance in the normal operation region.

  As shown in FIGS. 9A to 9C, when the magnetization boundary C of the driving magnet 22a is positioned on the sensitivity center point S of the Hall element 24a, the driving is performed as shown in FIG. 9B. When the working magnet 22a rotates, the output signal from the Hall element 24a is zero even when the driving magnet 22 moves in the direction of the magnetization boundary line C as shown in FIG. 9C. As shown in FIGS. 9D to 9F, when the magnetization boundary line C of the driving magnet 22a deviates from the sensitivity center point S of the Hall element 24a, the sensitivity center point S and the magnetization boundary are separated. A signal proportional to the distance r of the line C is output from the Hall element 24a. Therefore, if the distance r from the sensitivity center point S to the magnetization boundary line C is the same, when the driving magnet 22a moves in a direction perpendicular to the magnetization boundary line C as shown in FIG. When the drive magnet 22a is translated and rotated as shown in Fig. 9 (e), or when it is translated in an arbitrary direction as shown in Fig. 9 (f), a signal having the same magnitude is output from the Hall element 24a. Is done.

  Although the Hall element 24a has been described here, the other Hall elements 24b and 24c also output similar signals based on the positional relationship with the corresponding driving magnets 22b and 22c. For this reason, based on the signals detected by the Hall elements 24a, 24b, and 24c, the position where the moving frame 14 is translated and rotated with respect to the fixed frame 12 can be specified.

Next, the locking mechanism of the moving frame 14 will be described with reference to FIGS. FIG. 15 is a diagram illustrating a state in which the moving frame 14 has been moved to the locking position.
As shown in FIG. 4, three rotation stop protrusions 13 having an L-shaped cross section extending radially inward are provided on the peripheral edge of the housing 11. The long side of the L-shape of each rotation stop projection 13 is directed substantially in the radial direction of the housing 11, and the short side is directed in the circumferential direction. The rotation stopper protrusions 13 are arranged at 120 ° intervals in the circumferential direction of the housing 11.

  Further, a leaf spring 15 that is an elastic engaging portion receiving portion for positioning is attached to each rotation stop projection 13. These leaf springs 15 are thin and thin plate-like members, and are bent into a triangular shape with one side protruding. One side of the triangle protruding is directed in the substantially circumferential direction of the housing 11 and is attached to the L-shaped short side of each rotation stop projection 13. Further, the remaining two sides of the triangle are configured to form a convex shape inward in the radial direction in the direction of the optical axis of the image blur correction lens 16. These two sides are configured such that the inner slope 15a facing the long side of each rotation stop projection 13 is steeper than the outer slope 15b located on the opposite side. That is, the angle formed between the inner inclined surface 15a and the circumferential tangent of the housing 11 is configured to be larger than the angle formed between the outer inclined surface 15b and the circumferential tangent.

  On the other hand, on the moving frame 14, three notches 14 a are formed at intervals of 120 ° in the circumferential direction of the moving frame 14 so as to surround each rotation stop projection 13 and the leaf spring 15. Further, adjacent positioning portions 17 are formed adjacent to these three notches 14a. Each engaging portion 17 is formed so as to extend substantially radially about the optical axis of the image blur correction lens 16. Further, on the opposite side of each notch 14 a, three escape portions 14 b are formed adjacent to each engaging portion 17. These escape portions 14b are formed so as to surround the leaf spring 15 when the moving frame 14 is moved to the locking position. In other words, by cutting out the three cutouts 14a and the escape portions 14b from the disc-shaped moving frame 14, three engagement portions 17 are formed between them.

  Further, as shown in FIG. 15, each engagement portion 17 is moved between each rotation stop projection 13 and the slope 15 a inside the leaf spring 15 when the moving frame 14 is moved to the locking position. So that it is positioned. Therefore, when the moving frame 14 is moved to the locking position, the engaging portion 17 presses the outer slope 15b to elastically deform the leaf spring 15 outward in the radial direction, and the moving frame 14 is locked. When reaching the position, the leaf spring 15 returns to the inside in the radial direction with its elastic deformation being reduced. When the moving frame 14 is released from the locking position, the inner slope 15a is pressed, and the leaf spring 15 is elastically deformed radially outward.

  Next, image blur prevention control by the actuator 10 will be described with reference to FIG. FIG. 10 is a block diagram showing signal processing in the controller 36. As shown in FIG. 10, the vibration of the lens unit 2 is detected momentarily by the two gyros 34 a and 34 b and is input to arithmetic circuits 38 a and 38 b that are lens position command signal generation means built in the controller 36. In the present embodiment, the gyro 34a is configured and arranged to detect the angular velocity of the yawing motion of the lens unit 2, and the gyro 34b is configured to detect the angular velocity of the pitching motion.

  The arithmetic circuits 38a and 38b generate lens position command signals for instructing in time series the position to which the image blur correction lens 16 should be moved, based on the angular velocities input from the gyros 34a and 34b every moment. That is, the arithmetic circuit 38a time-integrates the angular velocity of the yawing motion detected by the gyro 34a and corrects predetermined optical characteristics to generate the horizontal component Dx of the lens position command signal. Similarly, the arithmetic circuit 38b Is configured to generate the vertical component Dy of the lens position command signal based on the angular velocity of the pitching motion detected by the gyro 34b. Even if the lens unit 2 vibrates during exposure for photography by moving the image blur correction lens 16 momentarily according to the lens position command signal thus obtained, the film surface in the camera body 4 The image focused on F is stabilized without being disturbed.

  The coil position command signal generating means built in the controller 36 is configured to generate a coil position command signal for each driving coil based on the lens position command signal generated by the arithmetic circuits 38a and 38b. The coil position command signal is obtained when each of the drive coils 20a, 20b, 20c and the corresponding drive magnets 22a, 22b, 22c when the image blur correction lens 16 is moved to the position specified by the lens position command signal. It is a signal showing the positional relationship. That is, when each driving magnet is moved to the position commanded by the coil position command signal for each driving coil, the image blur correction lens 16 is moved to the position commanded by the lens position command signal. Is done. In the present embodiment, since the driving coil 20a is provided vertically above the optical axis, the coil position command signal ra for the driving coil 20a is a horizontal component of the lens position command signal output from the arithmetic circuit 38a. It becomes equal to Dx. Accordingly, the arithmetic circuit 40a, which is a coil position command signal generating means for generating a coil position command signal for the driving coil 20a, outputs the output as it is from the arithmetic circuit 38a. On the other hand, the coil position command signals rb and rc for the drive coils 20b and 20c are generated by arithmetic circuits 40b and 40c, which are coil position command signal generation means, based on the horizontal component Dx and the vertical component Dy of the lens position command signal. Generated.

  On the other hand, the movement amount of the driving magnet with respect to each driving coil, measured by the Hall elements 24a, 24b, and 24c, is amplified to a predetermined magnification by the magnetic sensor amplifiers 42a, 42b, and 42c. The drive circuits 44a, 44b, and 44c differ in the difference between the coil position command signals ra, rb, and rc output from the arithmetic circuits 40a, 40b, and 40c and the signals output from the reflection sensor amplifiers 42a, 42b, and 42c. A proportional current is passed through each drive coil 20a, 20b, 20c. Accordingly, when there is no difference between the coil position command signal and the output from each reflection sensor amplifier, that is, when each driving magnet reaches the position commanded by the coil position command signal, no current flows through each driving coil. The driving force acting on the driving magnet becomes zero. The changeover switch 45 disposed between the arithmetic circuits 40a, 40b, and 40c and the drive circuits 44a, 44b, and 44c is always in a position that directly connects the arithmetic circuit and the drive circuit in the image blur prevention control mode. Yes. Further, the open / close switch 46 disposed between the drive circuits 44a, 44b, 44c and the drive coils 20a, 20b, 20c is always at a position where the drive circuit and the drive coil are connected in the image blur prevention control mode. Has been.

  Next, the relationship between the lens position command signal and the coil position command signal when the moving frame 14 is translated will be described with reference to FIG. FIG. 11 is a diagram showing the positional relationship between the driving coils 20 a, 20 b, 20 c arranged on the fixed frame 12 and the driving magnets 22 a, 22 b, 22 c arranged on the moving frame 14. First, the center points of the three drive coils 20a, 20b, and 20c are arranged on the points Sa, Sb, and Sc on the circumference of the radius R with the point Q as the origin. The Hall elements 24a, 24b, and 24c are also arranged so that their sensitivity center points S are located on the points Sa, Sb, and Sc. Further, when the moving frame 14 is at the operation center position, the center of the image blur correcting lens 16 and the optical axis of the imaging lens 8 coincide, and the magnetization boundary of each driving magnet corresponding to each driving coil. The midpoint of the line C is also located on each of the points Sa, Sb, and Sc, and each magnetization boundary line C is directed in the radial direction of a circle centered on the point Q. The moving frame 14 is translated around the operation center position, and image blur prevention control is executed.

  Next, the horizontal axis with the point Q as the origin is the X axis, the vertical axis is the Y axis, and the center point Q1 of the image stabilizing lens 16 is Dy, X in the Y axis direction as shown by the solid line in FIG. Consider a case in which -Dx translation is performed in the axial direction. When the moving frame 14 is moved in this manner, the magnetization boundary line C of each of the driving magnets 22a, 22b, and 22c is moved to the position indicated by the alternate long and short dash line in FIG. Here, the distance between the magnetization boundary line C of the driving magnet 22a and the point Sa is ra, the distance between the magnetization boundary line C of the driving magnet 22b and the point Sb is rb, and the driving magnet 22c Let rc be the distance between the magnetization boundary line C and the point Sc. The distances ra, rb, and rc correspond to the movement distances detected by the hall elements 24a, 24b, and 24c when the image stabilizing lens 16 is moved in the Y-axis direction by Dy and in the X-axis direction. . These distances ra, rb, and rc are uniquely determined with respect to the movement distances Dx and Dy in the X-axis direction and the Y-axis direction. Therefore, in order to move the image stabilizing lens 16 in the X-axis direction and the Y-axis direction by Dx and Dy, respectively, the distances ra, rb, and rc corresponding thereto may be given as coil position command signals.

図１０において説明した各演算回路４０ａ、４０ｂ、４０ｃは、夫々上記数式１に対応する演算を実行して、各コイル位置指令信号を生成している。 Here, when the positive directions of the distances ra, rb, and rc are defined as indicated by arrows a, b, and c in FIG. 10, the relationship between ra, rb, rc and Dx, Dy is as follows (Formula 1): Given in.

Each arithmetic circuit 40a, 40b, 40c demonstrated in FIG. 10 performs the calculation corresponding to the said Numerical formula 1, respectively, and has produced | generated each coil position command signal.

によって与えられる。このように、各駆動用磁石が各駆動用コイルに対して同一距離接線方向に移動されることにより、移動枠１４は、像振れ補正用レンズ１６の光軸と撮像用レンズ８の光軸が一致した状態を保持しながら、光軸を中心に回転される。 Next, a coil position command signal when the moving frame 14 is rotated will be described. In order to rotate the moving frame 14, the same value may be given as each coil position command signal. That is, each coil position command signal for rotating the moving frame 14 clockwise by an angle θ [rad] is:

Given by. In this way, each drive magnet is moved in the tangential direction at the same distance with respect to each drive coil, so that the moving frame 14 has an optical axis of the image blur correction lens 16 and an optical axis of the imaging lens 8. It is rotated around the optical axis while maintaining the coincidence state.

  Next, the operation of the camera 1 according to the first embodiment of the present invention will be described with reference to FIGS. First, an actuator 10 provided in the lens unit 2 is operated by turning on a start switch (not shown) for the camera shake prevention function of the camera 1. The gyros 34a and 34b attached to the lens unit 2 detect vibrations in a predetermined frequency band every moment and output them to the arithmetic circuits 38a and 38b built in the controller 36. The gyro 34a outputs an angular velocity signal in the yawing direction of the lens unit 2 to the arithmetic circuit 38a, and the gyro 34b outputs an angular velocity signal in the pitching direction to the arithmetic circuit 38b. The arithmetic circuit 38a integrates the input angular velocity signal with respect to time to calculate a yawing angle, and adds a predetermined optical characteristic correction thereto to generate a horizontal lens position command signal Dx. Similarly, the arithmetic circuit 38b integrates the input angular velocity signal with respect to time to calculate a pitching angle, adds a predetermined optical characteristic correction thereto, and generates a vertical lens position command signal Dy. An image focused on the film surface F of the camera body 4 by moving the image blur correction lens 16 momentarily to a position commanded by a lens position command signal output in time series by the arithmetic circuits 38a and 38b. Is stabilized.

  The horizontal lens position command signal Dx output by the arithmetic circuit 38a is output as a coil position command signal ra for the driving coil 20a via the arithmetic circuit 40a. Further, the horizontal lens position command signal Dx and the vertical lens position command signal Dy are input to the arithmetic circuit 40b, and a coil position command signal rb for the drive coil 20b is generated based on the middle expression of Equation 1. Is done. Similarly, the lens position command signals Dx and Dy are input to the arithmetic circuit 40c, and the coil position command signal rc for the drive coil 20c is generated based on the lower expression of Expression 1.

  On the other hand, the Hall element 24a corresponding to the driving coil 20a outputs a detection signal to the magnetic sensor amplifier 42a. The detection signal amplified by the magnetic sensor amplifier 42a is subtracted from the coil position command signal ra for the drive coil 20a, and a current proportional to these differences is output to the drive coil 20a via the drive circuit 44a. Similarly, a current proportional to the difference between the detection signal of the hall element 24b and the coil position command signal rb is output to the driving coil 20b via the drive circuit 44b, and the difference between the detection signal of the hall element 24c and the coil position command signal rc. Is output to the drive coil 20c via the drive circuit 44c.

  When a current flows through each driving coil, a magnetic field proportional to the current is generated. Due to this magnetic field, each driving magnet arranged corresponding to each driving coil receives a driving force in a direction approaching the position specified by the coil position command signals ra, rb, rc, and the moving frame 14 is moved. The When the driving magnet reaches the position specified by the coil position command signal by this driving force, the coil position command signal and the detection signal of the Hall element coincide with each other, so the output of the driving circuit becomes zero and the driving force also becomes zero. In addition, when each driving magnet deviates from the position specified by the coil position command signal due to a disturbance or a change in the coil position command signal, a current flows again to each driving coil. The position is returned to the position specified by the position command signal.

  By repeating the above operation every moment, the image blur correction lens 16 attached to the moving frame 14 having each driving magnet is moved so as to follow the lens position command signal. Thereby, the image focused on the film surface F of the camera body 4 is stabilized.

  Next, the operation of the locking position moving means 37 built in the controller 36 will be described with reference to FIGS. FIG. 12 shows the state of the open / close switch 46 built in the controller 36 in the upper stage, the state of the changeover switch 45 in the middle stage, the output signal of the locking position moving means 37 in the lower solid line, and the rotational position of the moving frame 14. It is a time-series graph shown in the lower broken line. FIG. 13 is a view showing a state where the leaf spring 15 in the middle of the movement frame 14 reaching the locking position is most elastically deformed. FIG. 14 is a view showing a state in which the moving frame 14 has passed the locking position and has come into contact with the rotation stop protrusion 13. FIG. 15 is a diagram illustrating a state in which the moving frame 14 has reached the locking position.

  First, when a locking switch (not shown) provided in the lens unit 2 is turned on at time t0 in FIG. 12, the locking position moving means 37 is activated. At the same time, as shown in the middle part of FIG. 12, the changeover switch 45 built in the controller 36 is connected to the locking position moving means 37 and the drive circuits 44a, 44b, 44c from the normal operation position (i). To the position (ii). As a result, the output signal of the locking position moving means 37 is input to each drive circuit instead of each coil position command signal ra, rb, rc.

  As indicated by the solid line in the lower part of FIG. 12, after the locking position moving means 37 is activated, a signal for moving the moving frame 14 to the locking preliminary operation position is output from time t0 to time t1. This preliminary operation position is the position shown in FIG. 4 where the optical axis of the image blur correction lens 16 and the optical axis of the imaging lens 8 coincide with each other in the direction opposite to the locking position, that is, 4 is set at a position rotated clockwise by a predetermined angle. When the locking position moving unit 37 outputs a signal for instructing the preliminary operation position at time t0, a current having a magnitude proportional to the deviation between the current position of the moving frame 14 and the preliminary operation position is generated in each of the driving coils 20a and 20b. 20c, and the moving frame 14 is driven. With this driving force, the moving frame 14 is moved to the preliminary operation position until time t1.

  Next, the locking position moving means 37 outputs a signal for accelerating the moving frame 14 toward the locking position from time t1 to time t2. The moving frame 14 is driven so as to follow this signal. That is, the moving frame 14 is accelerated counterclockwise in FIG. 4 while maintaining the state in which the optical axis of the image blur correction lens 16 and the optical axis of the imaging lens 8 coincide with each other. As a result, the moving frame 14 reaches the driving force cutoff position at time t2.

  Next, the locking position moving means 37 turns off the open / close switch 46 at time t2. Thereby, the current flowing through each driving coil is cut off, and the driving force for moving the moving frame 14 becomes zero regardless of the output signal of the locking position moving means 37. In the present embodiment, each driving coil and each driving magnet has a relative position shown in FIG. 7C as a driving force cutoff position.

  The moving frame 14 accelerated counterclockwise continues to rotate counterclockwise due to its inertia even after the driving force is cut off at time t2. When the moving frame 14 is rotated counterclockwise, the distal end of the engaging portion 17 is pressed against the inclined surface 15b of the leaf spring 15 while being pressed to elastically deform the leaf spring 15 outward in the radial direction. . As shown in FIG. 13, the amount of elastic deformation of the leaf spring 15 is maximized at the position where the tip of the engagement portion 17 and the convex vertex of the leaf spring 15 abut. Since the slope of the slope 15b is formed more gently than the slope of the slope 15a, the tip of the engaging portion 17 can elastically deform the leaf spring 15 with a relatively weak force. When the moving frame 14 is further rotated counterclockwise, the engaging portion 17 passes through the leaf spring 15, thereby reducing the amount of elastic deformation of the leaf spring 15.

  When the engaging portion 17 passes the leaf spring 15, the moving frame 14 is rotated to the position shown in FIG. 14 where the engaging portion 17 and the rotation stop projection 13 abut. In the position shown in FIG. 14, the engaging portion 17 is located between the rotation stop protrusion 13 and the convex portion of the leaf spring 15, and the convex portion of the leaf spring 15 is formed on the moving frame 14. Is received in the escape portion 14b. In a state where the engaging portion 17 has passed through the leaf spring 15, the drive magnets 22a, 22b, 22c and the attraction yokes 26 (illustrated by imaginary lines in FIG. 14) have the positional relationship shown in FIG. . In this state, the attractive force acting between each drive magnet and each attractive yoke exerts a clockwise rotational force in FIG.

  Due to this rotational force, the moving frame 14 is rotated clockwise, and the tip of each engaging portion 17 is pressed against the inclined surface 15 a of the leaf spring 15. When the tips of the three engaging portions 17 are pressed against the inclined surfaces 15a, the respective leaf springs 15 are slightly elastically deformed, and the moving frame 14 is locked at a predetermined locking position without looseness. At this locking position, the optical axis of the image blur correction lens 16 attached to the moving frame 14 and the optical axes of the other imaging lenses 8 substantially coincide. In the present embodiment, the drive magnet and the attraction yoke constitute a rotation urging means.

  Further, since the slope 15a against which the engaging portion 17 is pressed at the locking position is formed steeper than the slope 15b, the engaging portion 17 gets over the slope 15a and releases the moving frame 14 from the locking position. Requires a relatively large rotational force. For this reason, even when an impact force or the like acts on the camera 1, the moving frame 14 is not accidentally released from the locking position, and the moving frame 14 is reliably held at the locking position.

  On the other hand, when returning the moving frame 14 from the locking position to the normal operation region, the controller 36 supplies a predetermined current to each driving coil. That is, in the locking position, the first magnet portion 22a1 of the driving magnet 22a and the second winding portion 20a2 of the driving coil 20a are opposed to each other. Therefore, when a current is passed through the driving coil 20a, a driving force is generated between the first magnet portion 22a1 of the driving magnet 22a and the second winding portion 20a2 of the driving coil 20a. When the clockwise driving force is generated in this way, the tip of the engaging portion 17 presses the inclined surface 15a, and the leaf spring 15 is elastically deformed radially outward. Thereby, the engaging part 17 gets over the slope 15a, the moving frame 14 is released from the locking position, and returns to the normal operation region.

  Here, when the moving frame 14 is returned from the locking position to the normal operating region, the direction of the current that flows through the driving coil 20a is opposite to the current that moves the moving frame 14 clockwise in the normal operating region. . Further, the moving frame 14 is accelerated clockwise from the locking position toward the normal operation region, and when the driving force blocking position shown in FIG. 7E is reached, the current flowing through each driving coil is blocked. Thereby, the moving frame 14 is returned to the normal operation region by its inertia.

According to the camera of the embodiment of the present invention, since the moving frame itself is rotated and locked, the moving frame is locked without providing a special actuator for driving a member such as a lock ring. Can do.
Further, according to the camera of the embodiment of the present invention, the moving frame is locked by the leaf spring bent in a triangular shape, so that the moving frame can be elastically supported with a simple structure.

  Furthermore, according to the camera of the embodiment of the present invention, the slope of the leaf spring that is pressed when the moving frame is released from the locking position is pressed when the moving frame is moved to the locking position. Since it is formed steeper than the slope on the side to be moved, it is possible to prevent the moving frame from being accidentally released from the locking position by an impact force or the like.

  Further, according to the camera of the embodiment of the present invention, the rotational force is applied to the moving frame at the locking position, and the engaging portion is pressed against the leaf spring, so that the moving frame is held at the locking position without play. Can do.

  Furthermore, according to the camera of the embodiment of the present invention, since the moving frame is held at the locking position by the leaf spring, the moving frame can be held at the locking position even after energization of the camera is stopped. .

  Furthermore, according to the camera of the embodiment of the present invention, since the locking position is set at a position where the optical axis of the image blur prevention lens coincides with the optical axis of the imaging lens, the moving frame is set at the locking position. When moving, it is possible to maintain a state in which the optical axes of the respective lenses are substantially coincident. Thereby, when moving to the locking position, the image formed on the imaging surface is not greatly shaken, and the user does not feel uncomfortable.

  Furthermore, according to the camera of the embodiment of the present invention, when the moving frame is moved to the locking position, the moving frame is accelerated toward the locking position, and then the driving force is made zero. As described above, the locking position can be set at a position where the first winding portion and the first magnet portion, and the second winding portion and the second magnet portion do not face each other. Thus, the locking position can be set at a position far away from the normal operation region without increasing the size of the driving coil and the driving magnet.

  As mentioned above, although preferable embodiment of this invention was described, a various change can be added to embodiment mentioned above. In particular, in the above-described embodiment, the present invention is applied to a film camera. However, the present invention can be applied to any camera for capturing a still image or a moving image, such as a digital camera or a video camera. The present invention can also be applied to a lens unit used with the camera body of these cameras.

  In the above-described embodiment, the elastic engagement portion receiving portion is configured by the plate spring. However, any other configuration that can be elastically deformed can be adopted as the elastic engagement portion receiving portion. For example, the elastic engagement portion receiving portion can also be configured by supporting a component that slides with respect to the engagement portion by an elastically deformable member such as a coil spring.

  Furthermore, in the above-described embodiment, the engaging portion is pressed against the leaf spring by the attracting force between the driving magnet and the attracting yoke at the locking position, but another configuration is adopted as the rotation biasing means. You can also For example, a dedicated magnet or magnetic material may be arranged on the moving frame and the fixed frame so as to apply a predetermined rotational force at the locking position. Alternatively, the rotation urging means can be constituted by an elastic member such as a spring.

It is sectional drawing of the camera by embodiment of this invention. FIG. 5 is a side cross-sectional view of an actuator with a moving frame at a position for image blur prevention control. It is the rear view which looked at the actuator from the camera body side. It is a rear view of the actuator which shows the state which removed the fixed frame. It is the front view which looked at the fixed frame from the lens unit front end side. (A) Side surface sectional drawing which follows the VI-VI line of FIG. 3, (b) It is a perspective view which shows the state of the magnetization of the magnet for a drive. (A) It is a graph which shows the relationship between the relative position of a drive coil and a drive magnet, and the drive force which a drive magnet receives, and (b)-(e) The drive coil in point b thru | or e in a graph It is a figure which shows the relative position of a driving magnet. It is a figure explaining the relationship between the movement of a drive magnet, and the signal output from a Hall element. It is a figure explaining the relationship between the movement of a drive magnet, and the signal output from a Hall element. It is a block diagram which shows the signal processing in a controller. It is a figure which shows the positional relationship of the drive coil arrange | positioned on the fixed frame, and the drive magnet arrange | positioned on the moving frame. The state of the open / close switch built in the controller is shown in the upper row, the changeover switch in the middle row, the output signal of the locking position moving means in the lower solid line, and the rotation position of the moving frame in the lower broken line. It is a graph. It is a figure which shows the state by which the leaf | plate spring in the middle of the movement frame reaching the latching position was elastically deformed most. It is a figure which shows the state which the moving frame passed the latching position and contact | abutted to the rotation stop protrusion. It is a figure which shows the state which the movement frame reached | attained the latching position.

Explanation of symbols

C Magnetization boundary line 1 Camera 2 Lens unit 4 Camera body 6 Lens barrel 8 Imaging lens 10 Actuator 11 Housing 12 Fixed frame 12a Raised portion 13 Rotation stop projection 14 Moving frame 14a Notch 14b Escape portion 14c Raised portion 15 Plate spring 15a Slope 15b Slope 15a Contact receiving surface 16 Image shake correction lens 17 Engaging portion 18 Steel ball 20a Driving coil 20a1 First winding portion 20a2 Second winding portion 20b Driving coil 20c Driving coil 22a Driving magnet 22a1 First magnet part 22a2 Second magnet part 22b Driving magnet 22c Driving magnet 24a Hall element 24b Hall element 24c Hall element 26 Suction yoke 28 Back yoke 34a Gyro 34b Gyro 36 Controller 37 Locking position moving means 38a Circuit 38b arithmetic circuit 38c arithmetic circuit 40a arithmetic circuit 40b arithmetic circuit 40c arithmetic circuit 42a magnetic sensor amplifier 42b magnetic sensor amplifier 42c magnetic sensor amplifier 44a driving circuit 44b drive circuit 44c drive circuit

Claims (6)

An actuator for translating the imaging lens in a plane perpendicular to its optical axis to prevent image blur;
A fixed part;
A movable part to which the imaging lens is attached;
A movable part supporting means for supporting the movable part so as to be movable on a plane parallel to the fixed part;
Drive means for translating and rotating the movable part relative to the fixed part;
A plurality of engaging portions provided in the movable portion;
Corresponding to each of the engaging portions, the fixed portion is provided, and the movable portion is elastically deformed by the engaging portions while the movable portion is rotated to a predetermined locking position. A plurality of elastic engagement part receiving parts that reduce the amount of elastic deformation when reaching the position and hold the movable part in the locking position;
An actuator comprising:   Each engaging portion is formed on the movable portion so as to extend radially with respect to the optical axis of the imaging lens, and each elastic engaging portion receiving portion is convex inward in the radial direction. The actuator according to claim 1, wherein the actuator is formed in a mold and is elastically deformed radially outward by being pressed by the engaging portion when the movable portion is moved to the locking position.   Each of the elastic engaging portion receiving portions has two inclined surfaces on which the engaging portions slide, and the inclined surface on the side pressed when the movable portion is released from the locking position is the movable portion. The actuator according to claim 2, wherein the actuator is formed steeper than a slope on a side to be pressed when moved to the locking position.   Furthermore, it has a rotation urging means for applying a rotational force to the movable part at the locking position, and by the rotational force, each of the engaging parts receives each of the elastic engaging part receiving parts at the locking position. The actuator according to claim 1, wherein the actuator is pressed against the actuator. A lens barrel;
A plurality of imaging lenses housed in the lens barrel;
The actuator according to any one of claims 1 to 4, wherein a part of the imaging lens is attached to the movable part,
A lens unit comprising: The camera body,
A lens unit according to claim 5;
A camera characterized by comprising:

Images