JP2008304532A - Actuator and lens unit equipped therewith, camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To move a movable part across a wide range when performing control for a second mode without lowering accuracy of image blur preventing control. <P>SOLUTION: An actuator (10) preventing image blur by 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) which movably supports the movable part; a driving means which is provided to move the movable part; a position detection means (24) which detects the position of the movable part; a control means (36) which controls to move the movable part so that an output signal from the position detection means may follow up a position command signal for commanding the position of the movable part when performing image blur preventing control; and a second mode control means (48) which maintains the position command signal at a predetermined value or within a predetermined range, and also offsets the output signal from the position detection means and inputs the offset signal to the control means when performing the control for the second mode in which the movable part is more largely displaced than when performing the image blur preventing control. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an actuator, a lens unit including the actuator, and a camera, and in particular, an actuator for translating an imaging lens in a plane orthogonal to the optical axis thereof to prevent image blur and a lens unit including the actuator. , About the camera.

  Japanese Unexamined Patent Publication No. 2006-119249 (Patent Document 1) describes an actuator. This actuator has an image blur correction lens attached to the movable part, and corrects the shake of the focused image by moving the movable part in translation. Further, when it is necessary to lock the image blur correction lens without performing image blur correction, the movable unit is rotated around the optical axis of the lens for image blur correction, The locking receiving portion provided in the periphery is engaged and locked.

JP 2006-119249 A

  In the actuator described in Japanese Patent Laid-Open No. 2006-119249, since the movable part itself is rotated and moved to the locking position, there is no need to provide a lock ring or the like for locking the movable part, and the lock ring or the like is driven. There is an advantage that no special driving means is required. However, in the actuator described in the above publication, there is a problem that when the movable part is moved to the locking position, the movable part must be moved much larger than when the movable part is moved in order to prevent image blur. That is, the locking receiving portion that is engaged with the movable portion at the locking position is largely away from the moving range in the image blur prevention control of the movable portion so that the movable receiving portion does not interfere with the movable portion during the image blur prevention control. It is necessary to provide it at a position that is out of place.

For this reason, in order to control the movable part so that it is moved to the locking position, the position of the movable part is detected in a much wider range than that during image blur prevention control, and the movable part is moved based on the detected position. Need to drive.
For example, when a position signal detected by a position sensor is converted into a digital signal by an A / D converter and a subsequent control calculation is executed, a range of signals that can be input to the A / D converter is set. It is necessary to set a wide range up to the signal range corresponding to the locking position.

  Here, when the number of bits of the digital signal generated by the A / D converter is constant, the resolution of the A / D conversion decreases and the control accuracy decreases as the range of the input analog signal is set wider. There is a problem of doing. In addition, in the signal range to be A / D converted, the portion other than the region used in the image blur prevention control is not used except during the movement to the locking position, which is the control in the second mode. There is a problem of becoming.

  On the other hand, when the position signal detected by the position sensor is processed as an analog signal, the voltage of the position signal changes in a wide range, which increases the restrictions on the circuit for processing the position signal. There is. For example, a controller to which a position signal is input needs to be supplied with a power supply voltage that exceeds the voltage range in which the position signal changes. Therefore, if the range in which the position signal changes is wide, it should be supplied to the controller. The power supply voltage becomes high. Accordingly, the power supply voltage in the portion beyond the position signal change range in the image blur prevention control is unnecessary during the image blur prevention control, and the power consumption of the controller is increased more than necessary. appear.

  Therefore, the present invention provides an actuator capable of controlling the movable part to move over a wide range during the control in the second mode without reducing the accuracy of the image blur prevention control, and a lens unit including the actuator, The aim is to provide a camera.

  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 supporting means for supporting the movable part so that the movable part can be moved on a plane parallel to the fixed part, and a driving means for moving the movable part relative to the fixed part; Position detecting means for detecting the position of the movable part, and driving means so that an output signal from the position detecting means follows a position command signal for instructing a position to move the movable part in translation during image blur prevention control. And controlling the position of the position command signal to a predetermined value or a predetermined range during the control in the second mode in which the movable unit is displaced more than the image blur prevention control, Position detection It is characterized by having a second mode control means for inputting to the control unit by offsetting the output signal from the means.

  In the present invention configured as described above, the movable portion to which the imaging lens is attached is supported by the movable portion support means with respect to the fixed portion, and is moved by the drive means. The position detection means detects the position of the movable part. The control unit controls the driving unit so that the output signal from the position detection unit follows the position command signal during the image blur prevention control. On the other hand, in the second mode control in which the movable part is displaced more than in the image blur prevention control, the second mode control means maintains the position command signal at a predetermined value or a predetermined range and also from the position detection means. Are offset and input to the control means. While the second mode control means maintains the position command signal at a predetermined value or a predetermined range, by offsetting the output signal from the position detection means, the movable part can be displaced and the movable part is greatly displaced. Even in this case, since the output signal from the position detection means is offset, the signal level input to the control means can be kept low.

  According to the present invention configured as described above, the signal level input from the position detection means to the control means via the second mode control means even when the movable part is greatly displaced during the second mode control. Therefore, the movable part can be moved over a wide range during the second mode control without reducing the accuracy of the image blur prevention control.

  In the present invention, it is preferable that the second mode control unit offsets the output signal from the position detection unit so that the movable unit is rotated about the optical axis of the imaging lens.

  According to the present invention configured as described above, the movable part is rotated around the optical axis of the imaging lens during the control in the second mode. There is no shaking and the operational feeling is not deteriorated.

  In the present invention, it is preferable that the position detection unit includes at least three sensors that detect a displacement in a substantially tangential direction of a circle centered on the optical axis of the imaging lens, and the second mode control unit includes: Similarly, the movable part is rotated by offsetting the output signal.

  According to the present invention configured as described above, since the movable portion is rotated by similarly offsetting the output signals from the sensors, the offset voltage signal can be generated with a simple configuration.

  In the present invention, it is preferable that the driving means includes at least three linear motors that include a driving coil and a driving magnet, and generate thrust in a substantially tangential direction of a circle around the optical axis of the imaging lens. The position detection means has a magnetic sensor for detecting the magnetism of the driving magnet of each linear motor.

  According to the present invention configured as described above, the driving magnet can be used for position detection, so that the configuration of the actuator can be simplified and the actuator can be miniaturized.

In the present invention, preferably, the second mode control means moves the movable part to a locking position where the movable part is rotated by a predetermined angle around the optical axis of the imaging lens and locked.
According to the present invention configured as described above, since the movable portion is locked by the rotational movement, it is possible to prevent the focused image from shaking greatly when the movable portion is moved to the locking position. .

  In the present invention, preferably, the second mode control means moves the movable part to a positioning position where the movable part is rotated by a predetermined angle around the optical axis of the imaging lens and the movable part is mechanically positioned.

  According to the present invention configured as described above, since the movable part is moved to the positioning position by the rotational movement, it is possible to prevent the focused image from shaking greatly when the movable part is positioned.

  In the present invention, preferably, the second mode control means converts the digital data generating means for outputting digital data giving a predetermined offset amount in time series and the digital data output from the digital data generating means into a voltage. And a D / A converter for offsetting the output signal from the position detecting means.

  According to the present invention configured as described above, an arbitrary offset voltage waveform can be easily generated by the D / A converter, so that the moving path of the movable part during the second mode control can be freely set. be able to.

In the present invention, preferably, the second mode control means includes a switch element, and a time constant circuit that outputs a predetermined offset voltage waveform when the switch element is turned on and off to offset an output signal from the position detection means, Have
According to the present invention configured as described above, the offset voltage waveform can be generated with a simple circuit.

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.
The camera of the present invention includes 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 is controlled to move over a wide range during the non-image blur prevention control without reducing the accuracy of the image blur prevention control. be able to.

  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 addition to the image blur prevention control that stabilizes the image, the camera 1 of the present embodiment moves the moving frame, to which the image blur correction lens 16 is attached, to the locking position as the second mode control. It is configured. 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 front view of the actuator 10 in which the moving frame is in the position of image blur prevention control, and shows a state where the sensor substrate is removed. FIG. 3 is a front view of the actuator 10 with the moving frame in the locking position. 4 is a side sectional view taken along line IV-IV in FIG. 3, and FIG. 5A is a side sectional view taken along line VV in FIG. FIG. 5B is a perspective view showing a magnetized state of the driving magnet.

  As shown in FIGS. 2 to 5, the actuator 10 includes a fixed frame 12 that is a fixed portion fixed in the lens barrel 6 and a movable portion that is supported movably with respect to the fixed frame 12. It has a frame 14 and three steel balls 18 (FIG. 4) which are movable part support means for supporting the moving frame 14. Further, the actuator 10 includes three driving coils 20a, 20b, and 20c attached to the fixed frame 12, and three drives attached to the moving frame 14 at positions corresponding to the driving coils 20a, 20b, and 20c, respectively. Magnets 22a, 22b, and 22c.

  Further, as shown in FIG. 5A, 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. Further, as shown in FIG. 4, the actuator 10 has an attracting magnet 30 that attracts the steel ball 18 to the moving frame 14. 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 FIG. 5 (a), Hall elements 24a, 24b, and 24c, which are magnetic sensors, are arranged inside the windings of the drive coils 20a, 20b, and 20c (FIG. 5). Only 24a is shown). 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. That is, each Hall element functions as a sensor that detects the displacement of each drive magnet in the substantially circumferential direction of a circle around the optical axis of the imaging lens. 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 for controlling the current flowing therethrough. Details of the controller 36 will be described later.

  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.

  The fixed frame 12 has a substantially donut plate shape with an edge on the outer periphery, and three driving coils 20a, 20b, and 20c are disposed thereon. As shown in FIG. 2, the centers of these three drive 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.

  The moving frame 14 has a generally donut plate shape, and is disposed in the fixed frame 12 so as to be surrounded by the edge of 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 magnetic force exerted by the driving 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. 5A 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. Further, as shown in FIG. 5B, the polarity of the driving magnet 22a also changes in the thickness direction. In FIG. 5B, 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, the driving force received by each driving magnet will be described with reference to FIGS. FIG. 6A 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 in the upper stage, and the relationship between the relative position and the output of the Hall element 24a in the lower stage. 6B to 6E show the relative positions of the driving coil and the driving magnet at points b to e in the graph.

  First, as shown in FIG. 5A, 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. 5A 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 a direction indicated by an arrow in FIG. 6B flows through the driving coil 20a, a current flows from the back of FIG. 5A toward the front side in the first winding portion 20a1 of the driving coil 20a. Flows, and a current flows through the second winding portion 20a2 from the near side of FIG. 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. 5A is generated.

  As shown in FIG. 6A, this driving force is obtained when the driving magnet 22a and the driving coil 20a are in the positional relationship shown in FIG. 6B, 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. 6C (point c in FIG. 6A), the driving force becomes zero. When the driving magnet 22a is further moved to reach the position shown in FIG. 6D (point d in FIG. 6A), 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, when the driving magnet 22a is moved leftward, the driving force decreases and becomes zero at the position shown in FIG. 6E (point e in FIG. 6A). 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. 6B 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 is flowing through the driving coil 20a, a left 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.

  Next, as shown in the lower part of FIG. 6A, the output of the Hall element 24a arranged inside the driving coil 20a is such that the driving magnet 22a and the driving coil 20a are positioned as shown in FIG. 6B. When there is a relationship, that is, when the magnetization boundary line C of the driving magnet 22a is located at the center of the driving coil 20a, it becomes almost zero. Further, the output of the Hall element 24a increases as the driving magnet 22a is moved rightward from the position shown in FIG. 6B, and the driving magnet 22a becomes maximum at the position shown in FIG. 6C. Conversely, the output of the Hall element 24a decreases as the driving magnet 22a is moved leftward from the position shown in FIG. 6B, and the driving magnet 22a is minimized at the position shown in FIG. 6E. .

  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 an image blur prevention control region where force is generated. Furthermore, the locking position at which the moving frame 14 is locked is set to a position that is greatly deviated from the image blur prevention control region. At this locking position, the output of the hall element 24a is the image blur prevention control region. It is much larger than the output within.

Next, the position detection of the moving frame 14 will be described with reference to FIGS.
7 and 8 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. 7, 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. 7, when the driving magnet 22a is displaced in the X-axis direction orthogonal to the magnetization boundary line C, that is, in the circumferential 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 approximately proportional to the distance during image blur correction control.

  As shown in FIGS. 8A to 8C, when the magnetization boundary line 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. 8B. 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. As shown in FIGS. 8D to 8F, 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. 8 (e), or when it is translated in an arbitrary direction as shown in FIG. 8 (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.
As shown in FIGS. 2 and 3, the fixed frame 12 is provided with three positioning receiving portions 15 that extend radially inward from the outer periphery thereof. The engagement receiving portions 15 are arranged at intervals of 120 ° in the circumferential direction of the fixed frame 12. In addition, three positioning engaging portions 17 are formed in the moving frame 14 at intervals of 120 ° in the circumferential direction of the moving frame 14 so as to come into contact with the respective engagement receiving portions 15. . Each engagement portion 17 is configured to come into contact with the contact receiving surface 15a of each engagement receiving portion 15 at the contact surface 17a.

  Further, as shown in FIG. 3, these three sets of the contact surface 17 a and the contact receiving surface 15 a have the moving frame 14 in which the optical axis of the image blur correction lens 16 and the optical axis of the imaging lens 8 coincide. When it is rotated in a state, it is formed so as to contact at the same time. That is, the moving frame 14 is mechanically positioned at the predetermined locking position shown in FIG. 3 by moving the moving frame 14 so that the three sets of positioning contact surfaces 17a and the contact receiving surface 15a simultaneously contact each other. Is done.

  Here, each abutment surface 17a and abutment receiving surface 15a are formed as planes oriented in the radial direction of a circle centered on the optical axis, but there is an inevitable shape error in the abutment plane. Therefore, microscopically, each contact surface 17a and the contact receiving surface 15a come into contact in a state close to point contact. Therefore, the position of the moving frame 14 is not completely defined by the two sets of contact surfaces 17a and the contact receiving surfaces 15a, and the other set of contact surfaces 17a and the contact receiving surfaces 15a are in contact. As a result, the locking position is uniquely defined. Further, at the locking position, the optical axis of the image blur correction lens 16 and the optical axis of the imaging lens 8 coincide.

  Further, as shown in FIGS. 2 and 3, three locking magnetic members 23 a, 23 b, 23 c, which are magnetic adsorption means, are spaced on the fixed frame 12 by 120 ° in the circumferential direction of the fixed frame 12. Open and arranged. In the locking position shown in FIG. 3, each locking magnetic material exerts a rotational force that rotates the moving frame 14 in the clockwise direction in FIG. 3 by an attractive force acting between each driving magnet. By this rotational force, each contact surface 17a is pressed against each contact receiving surface 15a, and the moving frame 14 is locked at the locking position. Accordingly, in the present embodiment, the drive magnets 22a, 22b, and 22c also function as part of the magnetic force attracting means. Further, in the normal operation region of the moving frame 14, each driving magnet and each locking magnetic material are sufficiently separated from each other, so that the attractive force acting between them is almost zero.

Next, a support mechanism for the moving frame 14 by the steel balls 18 will be described with reference to FIGS.
As shown in FIGS. 2 and 3, the three steel balls 18 are respectively disposed between the fixed frame 12 and the moving frame 14. The three steel balls 18 are arranged at intervals of a central angle of 120 °, and the steel balls 18 are arranged between the drive coils. As shown in FIG. 4, each steel ball 18 is attracted to the moving frame 14 by an attracting magnet 30 embedded at a position corresponding to each steel ball 18 of the moving frame 14. Each steel ball 18 is attracted to the moving frame 14 by the attracting magnet 30, and the moving frame 14 is attracted to the fixed frame 12 by the driving magnet 22, so that each steel ball 18 is interposed between the fixed frame 12 and the moving frame 14. It will be pinched. 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, with reference to FIG. 9, the configuration of the controller 36 which is a control unit and the image blur prevention control by the actuator 10 will be described. FIG. 9 is a block diagram showing signal processing in the controller 36. As shown in FIG. 9, the controller 36 includes buffer amplifiers 37a and 37b to which angular velocity signals detected by the two gyros 34a and 34b are input, and arithmetic circuits 38a and 38b, which are lens position command signal generation means, Arithmetic circuits 40a, 40b and 40c, which are coil position command signal generating means, and drive circuits 44a, 44b and 44c are incorporated.

  As shown in FIG. 9, the vibration of the lens unit 2 is detected momentarily by the two gyros 34a and 34b, and is input to the arithmetic circuits 38a and 38b which are lens position command signal generation means via the buffer amplifiers 37a and 37b. The 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. Note that the selector switch 46 provided between the buffer amplifiers 37a and 37b and the arithmetic circuits 38a and 38b is always switched to a position where each buffer amplifier and each arithmetic circuit are directly connected during image blur prevention control. .

The buffer amplifiers 37a and 37b are configured to amplify the angular velocity signals detected by the gyros 34a and 34b to a predetermined magnification, respectively.
Arithmetic circuits 38a and 38b are position command signals for commanding in time series the positions to which the image blur correction lens 16 should be moved based on the angular velocities that are momentarily input from the gyros 34a and 34b through the buffer amplifiers 37a and 37b. A lens position command signal is generated. 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 generates a coil position command signal that is a position command signal for each driving coil based on the lens position command signals generated by the arithmetic circuits 38a and 38b. It is configured. 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 amount of movement of the driving magnet with respect to each driving coil measured by the Hall elements 24a, 24b, and 24c is predetermined by the magnetic sensor amplifier 50 built in the locking position moving means 48 that is the second mode control means. Is amplified to a magnification of. The drive circuits 44 a, 44 b, 44 c each output a current proportional to the difference between each coil position command signal ra, rb, rc output from the arithmetic circuits 40 a, 40 b, 40 c and the signal output from the magnetic sensor amplifier 50. The current flows through the driving coils 20a, 20b, and 20c. Therefore, when there is no difference between the coil position command signal and the output from each magnetic sensor amplifier, that is, when each drive magnet reaches the position commanded by the coil position command signal, no current flows through each drive coil. The driving force acting on the driving magnet becomes zero.

  The configuration and operation of the locking position moving means 48 and the magnetic sensor amplifier 50 will be described later. Note that the magnetic sensor amplifier 50 acts to simply amplify the output of the Hall elements 24a, 24b, and 24c to a predetermined magnification during image blur prevention control.

  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. 10 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 way, the magnetization boundary line C of each of the drive 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９において説明した演算手段４０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.

The calculation means 40 described in FIG. 9 generates the respective coil position command signals by executing calculations corresponding to the above mathematical formula 1.

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 configuration of the locking position moving means 48 will be described with reference to FIGS. FIG. 11 is a diagram showing an example of a circuit of the magnetic sensor amplifier 50 built in the locking position moving means 48. As shown in FIG.

  As shown in FIG. 9, the locking position moving means 48, which is the second mode control means, includes a magnetic sensor amplifier 50 to which the output signals of the hall elements 24a, 24b, 24c are inputted, and an output of the magnetic sensor amplifier 50. And a D / A converter 52a that outputs an offset signal for offsetting, and a memory 52b that is a digital data generation means that stores data of a predetermined offset signal. Further, the locking position moving means 48 includes a switch switching means 54a for switching the changeover switch 46 built in the controller 36, and a constant voltage supply means for supplying a constant voltage corresponding to zero angular velocity to one terminal of the changeover switch 46. 54b.

  The memory 52b stores digital data that gives a predetermined offset amount in time series, and the D / A converter 52a is configured to read this data and output a predetermined offset voltage waveform.

  The switch switching means 54a is configured to switch the changeover switch 46 to a position where the buffer amplifiers 37a, 37b and the arithmetic circuits 38a, 38b are directly connected or a position where the constant voltage supply means 54b and the arithmetic circuits 38a, 38b are connected. ing. The switch switching means 54a switches the changeover switch 46 to a position where the buffer amplifier and the arithmetic circuit are directly connected during the image blur prevention control, and constant voltage supply means during the movement of the moving frame 14 to the locking position. 54b is configured to switch to a position connected to the arithmetic circuit.

  The constant voltage supply means 54b is configured to output a voltage corresponding to the output voltage when the gyros 34a and 34b detect zero angular velocity. Therefore, when the constant voltage supply means 54b and the arithmetic circuits 38a and 38b are connected, the controller 36 operates in the same manner as when the lens unit 2 is stationary. That is, the arithmetic circuits 38a and 38b output zero as the lens position command signals Dx and Dy, respectively, and the arithmetic circuits 40a, 40b and 40c output zero as the coil position command signals ra, rb and rc, respectively.

  As shown in FIG. 11, the magnetic sensor amplifier 50 has six operational amplifiers OP11 to OP32 and 18 electric resistors R11 to R36. In FIG. 11, ancillary circuits of the magnetic sensor amplifier such as a power supply circuit are omitted. Each Hall element 24a, 24b, 24c has four terminals No. 1 to No. 4, and the No. 1 and No. 3 terminals are respectively connected to a + 3V power source and GND. Further, the detection signal of the Hall element is output as a difference signal between the second and fourth terminals.

  The second terminal of the hall element 24a is connected to the negative input terminal of the operational amplifier OP11 through the electric resistor R11. On the other hand, the fourth terminal of the hall element 24a is connected to the plus input terminal of the operational amplifier OP11 via the electric resistor R12. The output terminal of the operational amplifier OP11 is connected to the negative input terminal of the operational amplifier OP11 through the electric resistor R13. Further, the positive input terminal of the operational amplifier OP11 is connected to a reference voltage of 1.5 V via an electric resistor R14. A power supply voltage of 3V is applied to the operational amplifier OP11. The operational amplifier OP11 and the electric resistors R11 to R14 constitute a first stage operational amplifier.

  Next, the output terminal of the operational amplifier OP11 is connected to the plus input terminal of the operational amplifier OP12. The negative input terminal of the operational amplifier OP12 is connected to the output terminal of the D / A converter 52a via the electric resistor R15. Further, the output terminal of the operational amplifier OP12 is connected to the negative input terminal of the operational amplifier OP12 via the electric resistor R16. Note that a power supply voltage of 3 V is applied to the operational amplifier OP12. The operational amplifier OP12 and the electric resistors R15 and R16 constitute a second-stage non-inverting amplifier. Note that the D / A converter 52a is configured to always output a reference voltage of 1.5 V during image blur prevention control. In this case, the second non-inverting amplifier is The output of the first stage operational amplifier is further amplified to a predetermined magnification. Further, when the moving frame 14 is moved to the locking position, a predetermined offset voltage waveform is output from the D / A converter 52a, whereby the output of the non-inverting amplifier is offset according to the offset voltage waveform.

  Here, the configuration of the operational amplifier and the non-inverting amplifier connected to the Hall element 24a has been described, but the operational amplifier and the non-inverting amplifier connected to the other Hall elements are also configured similarly.

  Next, with reference to FIG. 1 and FIG. 9, the operation at the time of image blur prevention control of the camera 1 according to the embodiment of the present invention will be described. 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 detection signals to the arithmetic circuits 38a and 38b via the buffer amplifiers 37a and 37b. 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 50 built in the locking position moving means 48. The magnetic sensor amplifier 50 amplifies the input signal to a predetermined magnification and outputs it during image blur prevention control. The detection signal amplified by the magnetic sensor amplifier 50 is subtracted from the coil position command signal ra for the drive coil 20a, and a current proportional to the difference between these 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.

  As described above, when a current flows through each driving coil, a driving force proportional to the current is generated. That is, the driving force in the direction approaching the position specified by the coil position command signals ra, rb, rc, respectively, when the current flows through each driving coil and the driving magnets arranged corresponding to the driving coils respectively. In response, the moving frame 14 is moved. 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 moving the moving frame 14 of the actuator 10 to the locking position will be described with further reference to FIGS. FIG. 12 is a timing chart showing signals at various parts when the moving frame 14 is moved to the locking position. 12 is a chart showing the switching state of the changeover switch 46, and the second stage shows the distance between the optical axis of the image blur correction lens 16 and the optical axis of the other imaging lens 8. The third row is a chart representing the output signal from the Hall element 24a, the fourth row is a chart representing the output signal from the D / A converter 52a, and the bottom row is the magnetic sensor amplifier 50. It is a chart showing the output signal from. FIG. 13 is a side sectional view showing the positional relationship between the driving coil 20a, the driving magnet 22a, and the locking magnetic material 23a at the locking position, and FIG. 14 is a front view.

  First, when a locking switch (not shown) provided in the lens unit 2 is turned on, the switch switching means 54a built in the locking position moving means 48 sends a signal to the switching switch 46 of the controller 36. (FIG. 9). Thereby, the changeover switch 46 is switched from the position where the buffer amplifiers 37a, 37b and the arithmetic circuits 38a, 38b are directly connected to the position where the constant voltage supply means 54b and the arithmetic circuits 38a, 38b are connected. That is, as shown in the uppermost stage of FIG. 12, the changeover switch 46 is switched to the locking movement position at time t1.

  When the constant voltage supply means 54b and the arithmetic circuits 38a and 38b are connected, a signal voltage equivalent to that when the lens unit 2 is stationary is input to the arithmetic circuits 38a and 38b. Thereby, the arithmetic circuits 38a and 38b output lens position command signals Dx and Dy for moving the moving frame 14 to the operation center position of the image blur prevention control shown in FIG. The controller 36 moves the moving frame 14 to the operation center position for image blur prevention control in accordance with the lens position command signals Dx and Dy. That is, as shown in the second chart of FIG. 12, the moving frame 14 is moved so that the optical axis of the image blur correction lens 16 matches the optical axis of the other imaging lens 8.

  As shown in FIG. 12, when the changeover switch 46 is switched at time t1, the moving frame 14 is moved to the operation center position of the image blur prevention control, and accordingly, the output voltage of the Hall element 24a (the second number of the Hall element 24a) is moved. The potential difference between the terminal and the fourth terminal) converges to zero (the third chart in FIG. 12). On the other hand, the D / A converter 52a outputs the reference voltage (1.5 V) until time t2 after a predetermined time has elapsed from time t1 (the fourth chart in FIG. 12). Therefore, during this period, the output of the magnetic sensor amplifier 50 is not offset, and the output voltage waveform of the magnetic sensor amplifier 50 is similar to the output voltage waveform of the Hall element 24a (the fifth stage in FIG. 12). Chart).

  The moving frame 14 is moved to the operation center position of the image blur prevention control by time t2 after a predetermined time after time t1. Therefore, at time t2, the optical axis of the image blur correction lens 16 and the optical axis of the other imaging lens 8 coincide with each other, the output voltage of the Hall element 24a becomes zero, and the D / A converter 52a and the magnetic sensor amplifier The output voltage of 50 is a reference voltage. Although not shown in FIG. 12, the output voltages of the other Hall elements 24b and 24c are zero at time t2.

  Next, at time t2, the D / A converter 52a outputs a predetermined offset voltage waveform based on the waveform data stored in the memory 52b (the fourth chart in FIG. 12). When an offset voltage is output from the D / A converter 52a, the output of the magnetic sensor amplifier 50 is offset by the offset voltage even when the output voltage of the Hall element 24a is maintained at zero. As a result, a difference occurs between the output corresponding to the Hall element 24a of the magnetic sensor amplifier 50 and the coil position command signal ra, and a current flows through the driving coil 20a. Further, since the outputs corresponding to the Hall elements 24b and 24c of the magnetic sensor amplifier 50 are similarly offset, a difference also occurs between these outputs and the coil position command signals rb and rc, and the drive coil 20b, A similar current flows through 20c.

  When the same current flows through each driving coil, a driving force for rotating the moving frame 14 around the optical axis is generated, and the moving frame 14 is rotated. The rotation of the moving frame 14 changes the output of the Hall elements 24a, 24b, and 24c so as to follow the offset voltage waveform from the D / A converter 52a (see the third and fourth charts in FIG. 12). ). Thus, since the output of each Hall element is changed so as to follow the offset voltage waveform, each output of the magnetic sensor amplifier 50 is maintained near the reference voltage regardless of the output voltage of each Hall element ( (See the bottom chart in FIG. 12). In other words, even when the output of each Hall element changes greatly due to a large rotational movement of the moving frame 14, the output change of each Hall element is caused by the offset voltage waveform output from the D / A converter 52a. The output of the magnetic sensor amplifier 50 is maintained near the reference voltage.

  Next, at time t3, the output of the D / A converter 52a reaches a predetermined maximum offset voltage and thereafter is maintained at that value. The moving frame 14 is rotated clockwise so as to follow the offset voltage waveform of the D / A converter 52a, thereby rotating clockwise to the locking position shown in FIG. 3 at time t3. As shown in FIG. 12, the offset voltage and the output of the Hall element are in a proportional relationship, but the offset voltage and the amount of rotational movement of the moving frame 14 are not in a proportional relationship. This is because, as described with reference to FIG. 6A, the rotational movement amount of the moving frame 14 and the output of each Hall element are not completely proportional.

  When the moving frame 14 is rotated clockwise to the locking position shown in FIG. 3, the contact surface 17 a of each engaging portion 17 and the contact receiving surface 15 a of each engagement receiving portion 15 are in contact with each other. The moving frame 14 is locked to the fixed frame 12.

  Further, in this locking position, as shown in FIGS. 13 and 14, the first magnet portion 22a1 of the driving magnet 22a and the locking magnetic material 23a approach each other, so that the driving magnet 22a is positioned on the right side in FIG. Attracted in the direction. Similarly, the first magnet portions 22b1 and 22c1 of the driving magnets 22b and 22c are also attracted to the locking magnetic materials 23b and 23c, and the moving frame 14 exerts the clockwise rotational force in FIG. receive. By this rotational force, the contact surface 17a of each engagement portion 17 is pressed against the contact reception surface 15a of each engagement reception portion 15, and the moving frame 14 is held in the locking position.

  On the other hand, when the moving frame 14 is returned from the locking position to the image blur prevention control region, the locking position moving means 48 converts the offset voltage waveform in the direction opposite to that when moving to the locking position to D / A conversion. Output from the device 52a. That is, in this case, the D / A converter 52a outputs a predetermined offset voltage waveform that changes from the maximum offset voltage stored in advance in the memory 52b to the reference voltage. As a result, the moving frame 14 is rotated counterclockwise so that the output from each Hall element follows the offset voltage waveform, and each driving magnet is separated from each locking magnetic material. Thereby, the moving frame 14 is returned from the locking position shown in FIG. 3 to the operation center position of the image blur prevention control shown in FIG.

  After the moving frame 14 is returned to the operation center position, the output of the D / A converter 52a is maintained at the reference voltage, and the locking position moving means 48 operates the changeover switch 46 with the buffer amplifiers 37a and 37b. The circuits 38a and 38b are switched to positions where they are directly connected. As a result, the camera 1 is returned to the image blur prevention control mode.

  According to the camera of the embodiment of the present invention, even when the moving frame is largely displaced when moving to the locking position during the second mode control, the controller from the hall element via the locking position moving means. The signal level input to can be kept low. Therefore, it is possible to move the moving frame in a wide range while making it possible to design the signal level of the position signal that can be input to the controller to be narrow. Furthermore, it is possible to prevent a reduction in accuracy of image blur prevention control and an increase in power consumption due to the expansion of the movable range of the moving frame.

  In addition, according to the camera of the present embodiment, the locking position is set at a position where the optical axis of the image blur correction lens and the optical axis of the other imaging lens coincide with each other. 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 present embodiment, since the moving frame is rotated by similarly offsetting the output signals from the hall elements, an offset voltage signal can be generated with a simple configuration.

  Further, according to the camera of the present embodiment, the Hall element detects the magnetism of the driving magnet and detects the position, so that the driving magnet can also be used for position detection. Thereby, the configuration of the actuator can be simplified and the actuator can be miniaturized.

  Further, according to the camera of the present embodiment, the Hall element detects the displacement in the substantially circumferential direction of the circle centered on the optical axis of the imaging lens, so that the rotational movement of the moving frame is detected by the output of each Hall element. In addition, the translational movement of the moving frame can be detected by calculating the output of each Hall element in combination.

  Furthermore, according to the camera of the present embodiment, since the moving frame itself is rotated and locked, the moving frame is locked without providing a special member such as a lock ring and an actuator for driving the member. can do.

  In addition, according to the camera of the present embodiment, the locking position is set at a position sufficiently away from the image blur correction control area of the moving frame. The part does not interfere.

  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 moving frame is moved to the locking position by the control in the second mode, and at this locking position, the moving frame is moved by the attractive force between the driving magnet and the locking magnetic material. It was locked. However, the moving frame may be simply positioned at the locking position without locking the moving frame at the locking position. In this case, the moving frame is moved to a predetermined positioning position by the control in the second mode, and the position detecting means and the like can be calibrated based on the mechanically positioned positioning position.

  Further, in the above-described embodiment, the controller controls the current flowing through each driving coil by the analog circuit, but the controller may be configured to execute control by digital processing. In this case, the controller can be configured such that a signal from the Hall element input via the locking position moving means is input via an A / D converter built in the controller. When the controller is configured in this way, it is possible to ensure high resolution of the A / D converter during image blur prevention control while enabling a wide range of movement of the moving frame.

  Further, in the above-described embodiment, when the locking position is moved, the locking position moving means gives the lens position command signal corresponding to the angular velocity = 0 to the controller, but the lens position command signal given to the controller is Can be set arbitrarily. Alternatively, the lens position command signal to be applied can be any signal that changes within a predetermined range. In this case, an offset voltage signal is set in accordance with the lens position command signal to be applied, and the locking position moving means is configured so that the moving frame is moved to the locking position by the superimposed signal. be able to.

  Furthermore, in the above-described embodiment, the offset voltage waveform is generated by the D / A converter and the memory. However, as a modification, the offset voltage waveform can be generated by an analog circuit. FIG. 15 is a circuit diagram of a time constant circuit as an example of an analog circuit that generates such an offset voltage waveform, and FIG. 16 is a graph showing an output waveform of this circuit.

  As shown in FIG. 15, the time constant circuit 60 includes an operational amplifier OP1, electric resistors R1 and R2, and a capacitor C1. Further, an analog switch 62 as a switch element is connected to the time constant circuit 60. One terminal of the electrical resistor R1 is connected to a 3V power source, and the other terminal is connected to one terminal of the electrical resistor R2. The other terminal of the electrical resistor R2 is grounded via the analog switch 62. Furthermore, a capacitor C1 is connected in parallel with the electric resistor R1. In this modification, the electric resistors R1 and R2 are set to the same resistance value. The positive input terminal of the operational amplifier OP1 is connected to the point where the electric resistors R1 and R2 are connected, and the output terminal of the operational amplifier OP1 is connected to the negative input terminal.

Next, the operation of the time constant circuit 60 will be described with reference to FIG.
First, as shown in FIG. 16A, when the analog switch 62 is turned on, a current flows from the 3V power source to the ground via the electric resistors R1 and R2 and the analog switch 62. Thereby, the power supply voltage is divided by the electric resistors R1 and R2, and the voltage at the connection point of the electric resistors R1 and R2 becomes about 1.5V. This voltage is input to the operational amplifier OP1 and output from the time constant circuit 60 as it is. Next, when the analog switch 62 is turned off at time t0, the current flowing from the power source to the ground is interrupted. As a result, the voltage at the connection point between the electric resistors R1 and R2 gradually increases to about 3 V according to the time constant set by the electric resistor R1 and the capacitor C1. This voltage change is output as it is through the operational amplifier OP1. With the output waveform of the time constant circuit 60, the moving frame 14 is moved from the operation center position of the image blur prevention control to the locking position.

  On the other hand, when the moving frame 14 is returned from the locking position to the operation center position of the image blur prevention control, the analog switch 62 is switched from the off state to the on state. As shown in FIG. 16B, when the analog switch 62 is turned off, almost no current flows through the electric resistor R1, so that no voltage drop occurs in the electric resistor R1. Therefore, the voltage at the connection point between the electric resistors R1 and R2 is substantially equal to the power supply voltage, and this voltage is output via the operational amplifier OP1. Next, when the analog switch 62 is turned on at time t0, a current flows from the power source to the ground. As a result, the voltage at the connection point between the electric resistors R1 and R2 gradually decreases to about 1.5 V according to the time constant set by the electric resistor R1 and the capacitor C1. This voltage change is output as it is through the operational amplifier OP1. With the output waveform of the time constant circuit 60, the moving frame 14 is moved from the locking position to the operation center position of the image blur prevention control.

It is sectional drawing of the camera by embodiment of this invention. FIG. 6 is a front view of an actuator having a moving frame at an operation center position of image blur prevention control. It is a front view of an actuator in which a moving frame is in a locking position. FIG. 4 is a side sectional view taken along line IV-IV in FIG. 3. FIG. 4A is a side cross-sectional view taken along the line V-V, and FIG. The graph (a) showing the relationship between the relative position of the driving coil and the driving magnet, the driving force received by the driving magnet and the Hall element output, and the driving coil and the driving magnet at points b to e in the graph It is a figure which shows relative position (b)-(e). 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 positional relationship of a driving magnet and 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. It is a figure which shows an example of the circuit of the magnetic sensor amplifier incorporated in the latching position moving means. It is a timing chart which shows the signal of each part at the time of moving a moving frame to a latching position. It is side surface sectional drawing which shows the positional relationship of the drive coil in the latching position, the drive magnet, and the latching magnetic material. It is a front view which shows the positional relationship of the drive coil in the latching position, the drive magnet, and the latching magnetic material. It is a circuit diagram of a time constant circuit which is an example of an analog circuit that generates an offset voltage waveform. It is a graph which shows the output waveform of a time constant circuit.

Explanation of symbols

C Magnetization boundary line 1 Camera 2 Lens unit 4 Camera body 6 Lens barrel 8 Imaging lens 10 Actuator 12 Fixed frame (fixed part)
13 Sensor board 14 Moving frame (movable part)
DESCRIPTION OF SYMBOLS 15 Engagement receiving part 15a Contact receiving surface 16 Image blur correction lens 17 Engaging part 17a Contact surface 18 Steel ball (movable part support means)
20a Driving coil 20a1 First winding part 20a2 Second winding part 20b Driving coil 20c Driving coil 22a Driving magnet 22a1 First magnet part 22a2 Second magnet part 22b Driving magnet 22c Driving magnet 23a For locking Magnetic material 23b Magnetic material for locking 23c Magnetic material for locking 24a Hall element (magnetic sensor)
24b Hall element (magnetic sensor)
24c Hall element (magnetic sensor)
26 Suction Yoke 28 Back Yoke 30 Suction Magnet 34a Gyro 34b Gyro 36 Controller (Control Unit)
37a, 37b Buffer amplifier 38a, 38b Arithmetic circuit (lens position command signal generating means)
40a, 40b, 40c arithmetic circuit (coil position command signal generating means)
44a, 44b, 44c Drive circuit 46 Changeover switch 48 Locking position moving means (second mode control means)
50 Magnetic sensor amplifier 52a D / A converter 52b Memory (digital data generating means)
54a Switch switching means 54b Constant voltage supply means 60 Time constant circuit 62 Analog switch (switch element)

Claims (10)

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;
Driving means for moving the movable part relative to the fixed part;
Position detecting means for detecting the position of the movable part;
At the time of image blur prevention control, the drive unit is controlled so that the output signal from the position detection unit follows a position command signal that commands the position where the movable unit should be translated. Control means to move;
In the second mode control in which the movable portion is displaced more than in the image blur prevention control, the position command signal is maintained at a predetermined value or a predetermined range, and an output signal from the position detection unit is offset. Second mode control means for inputting to the control means,
An actuator comprising:   2. The actuator according to claim 1, wherein the second mode control unit offsets an output signal from the position detection unit so that the movable part is rotated about the optical axis of the imaging lens. 3.   The position detection means has at least three sensors for detecting a displacement in a substantially tangential direction of a circle centered on the optical axis of the imaging lens, and the second mode control means outputs an output signal from each sensor. The actuator according to claim 2, wherein the movable portion is rotationally moved by offsetting the same.   The drive means includes a drive coil and a drive magnet, and has at least three linear motors that generate thrust in a substantially tangential direction of a circle centered on the optical axis of the imaging lens, and the position detection means The actuator according to any one of claims 1 to 3, further comprising a magnetic sensor that detects magnetism of the driving magnet of each of the linear motors.   5. The second mode control means according to claim 1, wherein the movable portion is rotated by a predetermined angle about the optical axis of the imaging lens and moves the movable portion to a locking position where the movable portion is locked. The actuator according to item 1.   The second mode control means moves the movable part to a positioning position where the movable part is rotated by a predetermined angle around the optical axis of the imaging lens and the movable part is mechanically positioned. 5. The actuator according to any one of items 4 to 4.   The second mode control means includes a digital data generating means for outputting digital data giving a predetermined offset amount in time series, and converting the digital data output from the digital data generating means into a voltage from the position detecting means. An actuator according to any one of claims 1 to 6, further comprising a D / A converter for offsetting the output signal.   2. The second mode control means includes a switch element and a time constant circuit that outputs a predetermined offset voltage waveform when the switch element is turned on / off to offset an output signal from the position detection means. The actuator according to any one of 1 to 6. A lens barrel;
A plurality of imaging lenses housed in the lens barrel;
The actuator according to any one of claims 1 to 8, wherein a part of the imaging lens is attached to the movable part,
A lens unit comprising: The camera body,
The lens unit according to claim 9,
A camera characterized by comprising:

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