JP2016033559A - Lens barrel having image tremor correction device loaded and optical device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image tremor correction device that has a linear property of a sensor output in a broad range although downsized in a direction orthogonal to an optical axis, and to provide an optical device that has the image tremor correction device loaded.SOLUTION: The present invention comprises: a first movement member that holds a tremor correction lens; a second movement member that movably supports a first movement frame in a plane surface orthogonal to an optical axis; a stationary member that movably supports a second movement frame in the plane surface orthogonal to the optical axis; at least two driving means that cause an urging member urging the first movement member and the second movement member against a base and the first movement member to be moved; at least two driving means that cause the second movement member to be moved: first location detection means that detects a relative location between the first movement member and the second movement member; second location detection means that detects a relative location between the second movement member and the stationary member; and control means that controls the locations of the first and second movement members in accordance with location information on the first and second location detection means. The first movement member is relatively movable to the second movement member, and the second movement member is relatively movable to the stationary member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical device, and more particularly to a lens barrel having an image blur correction device in an optical device such as a digital still camera or a video camera, and an optical device equipped with the lens barrel.

  In an optical apparatus such as a digital camera, there is an image blur correction device for correcting an optical axis shift caused by camera shake at the time of photographing and performing optical image stabilization. In general, the image blur correction apparatus is a lens barrel provided in an optical apparatus, in which an image blur correction lens group is shifted in a plane orthogonal to the optical axis.

  Patent Document 1 employs a so-called moving coil type shift unit in which a driving magnet magnetized in two poles is disposed on a base member on the fixed side, and a yoke and a coil are disposed on the shift member on the movable side. An image blur correction apparatus is disclosed. In this shift unit, three balls are arranged between the base member and the shift member, and the shift member is urged against the base member by a magnetic attraction force acting between the drive magnet and the yoke, thereby holding the ball. I am letting. At this time, since the movement of the shift member in the optical axis direction is restricted by the ball, the shift member shifts only within the plane orthogonal to the optical axis while rolling the ball by the Lorentz force acting between the coil and the driving magnet. In addition, a Hall element, which is a position detecting means for detecting the position of the shift member, is arranged in the coil, and the position is detected and controlled by converting the magnetic flux density of the driving magnet into an electric signal. Downsizing of the shift unit is achieved by arranging the Hall element in the coil and sharing the position detection magnet with the drive magnet.

  In general, the position detecting means generally has the structure disclosed in Patent Document 2. Patent Document 2 is fixed to an S pole and an N pole magnet arranged adjacent to each other, and a member that is relatively movable with respect to these magnets so as to be positioned between the magnets in an initial state, At least one magnetic detection means for detecting the relative position of the member, and the relative position of the movable member by detecting a change in the magnetic field due to relative displacement between the magnet and the magnetic detection means Is detected.

  FIG. 1 shows the relationship between the movement amount and the sensor output. In the above-described position detection configuration, the sensor output must be used in the range of the movement amount A in which the moving member is approximately linear in order to maintain the position detection accuracy of the moving member. However, the position detection accuracy of the movable member is lowered, and there are cases where the optical performance is deteriorated during image stabilization and the image blur correction remains.

Patent Document 3 is disclosed as a countermeasure against the linearity problem. Patent Document 3 includes a magnetic field generating member attached to a movable member movable in a movable direction, and a magnetic field detecting means by movement of the magnetic field generating member, and the magnetic field generating member is an N magnetized to an N pole. A pole portion, an N pole portion, an S pole portion arranged in the movable direction, and a non-magnetized portion between the N pole portion and the S pole portion. It has a magnetic field detection element for detecting two magnetic field changes arranged in the movable direction, and the detection signal of the two magnetic field detection elements is A in the smaller diameter range and B in the larger diameter range,
When A> 0 (A−B) / (A + B) +2,
When B <0 (A−B) / (A + B) +2,
When A ≦ 0 and B ≧ 0, (B + A) / (BA)
By performing this calculation, an output having a diameter in a wide range is obtained.

Japanese Unexamined Patent Publication No. 2011-150086 JP-A-8-136207 JP 2006-292396 A

  However, when the position detection method using two Hall elements shown in Patent Document 3 is applied to the image blur correction apparatus described in Patent Document 1, two Hall elements are provided in the coil as shown in FIG. In order to arrange | position, there existed a subject that it enlarged in the Hall element spectral-axis orthogonal direction.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image blur correction device having a linearity of sensor output in a wide range while being small in the direction perpendicular to the optical axis, and an optical apparatus equipped with the image blur correction device.

  In order to achieve the above object, the configuration of the image blur correction device according to the present invention is configured to hold a shake correction lens and to move the first moving member and the first moving frame in a plane orthogonal to the optical axis. A second moving member to be supported; a fixed member that supports the second moving frame so as to be movable in a plane perpendicular to the optical axis; and a biasing force that biases the first moving member and the second moving member to the base. A biasing member, at least two driving means for moving the first moving member, at least two driving means for moving the second moving member, and the relative relationship between the first moving member and the second moving member. Position information of the first position detecting means for detecting the position, the second position detecting means for detecting the relative position of the second moving member and the fixed member, and the position information of the first and second position detecting means And a control means for controlling the positions of the first and second moving members by the first moving section. Is movable relative to the second moving member, and wherein the second movable member is movable relative to the stationary member.

  ADVANTAGE OF THE INVENTION According to this invention, the camera-shake correction apparatus which has the linearity of a sensor output in a wide range, and an optical apparatus carrying it can be provided, although it is small in the optical axis orthogonal direction.

Sectional view showing the present invention Video camera body and lens barrel equipped with the present invention Sectional view of a lens barrel equipped with the present invention Exploded perspective view of the present invention Explanatory drawing about movement of the present invention Control part of image blur correction apparatus of the present invention Comparison of space efficiency between the present invention and FIG. Explanatory drawing regarding position detection described in Patent Document 1 Explanatory diagram for position detection when two Hall elements are used

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in the description of the image blur correction device according to the embodiment of the present invention, the lens barrel in which the image blur correction device is installed is employed in an imaging device (optical device) such as a video camera or a digital still camera. To do. In each of the following drawings, the X axis is the optical axis direction of the lens barrel, the Y axis is the vertical direction (pitch direction), and the horizontal direction (the yaw direction) is the Z axis in the plane perpendicular to the X axis. explain.

  FIG. 2 is a diagram showing a configuration of an optical apparatus (hereinafter referred to as a camera) such as a video camera or a digital camera according to an embodiment of the present invention. In (a), L represents a lens barrel capable of zooming, and B represents a camera body. (B) is a perspective view of the lens barrel L according to the present invention mounted in the camera body B, and the subject image formed by the photographing optical system of the lens barrel L is an image pickup attached to the rear part of the lens barrel. Recorded by the element.

  3 is a cross-sectional view taken along the XY plane passing through the optical axis of the lens barrel L. FIG. The photographing optical system is a variable magnification optical system (zoom lens) composed of four lens groups L1 to L4.

  L1 is a first group lens and is held by a first group lens holding frame 101. L2 is a second group lens, and is held by the second group lens moving frame 201. The second group lens moving frame 201 is supported by a guide shaft (not shown) so as to be movable only in the optical axis direction. The second group lens moving frame 201 is moved by a stepping motor (not shown) to change the image to be formed. L3 is an anti-vibration lens that is held by the first anti-vibration moving frame 311 and supported by the fixing member 331 so as to be movable in a plane orthogonal to the optical axis. The image blur is corrected by moving the anti-vibration lens in a plane orthogonal to the optical axis. The details of the blur correction apparatus will be described separately along with the contents of the present invention. L4 is a fourth lens group, and is held by the fourth lens group moving frame 401. The fourth group lens L4 is supported by a guide shaft (not shown) so as to be movable in the optical axis direction, and adjusts the focal position of the image formed by moving in the optical axis direction by a stepping motor (not shown).

  Reference numeral 501 denotes an aperture unit that adjusts the amount of light by moving the two aperture blades 502 and 503 in the direction perpendicular to the optical axis. Reference numeral 601 denotes an image sensor holder that holds an image sensor that converts an image obtained through each of the lens groups L1 to L4 into an electric signal and a stepping motor (not shown). Reference numeral 701 denotes a front sleeve that sandwiches the image blur correction device L3 and a guide shaft (not shown) between the image sensor holder 601 and the front sleeve. Further, the first group lens holding frame 101 is positioned and held in the optical axis direction.

  It is possible to record a desired image by appropriately controlling each of these drive mechanisms through a camera control unit by a user's camera operation and a flexible printed circuit board (FPC) 341 that transmits signals to each mechanism unit. is there.

  Next, the image blur correction apparatus of the present invention will be described with reference to FIGS. L3 is a correction lens for performing image blur correction. Reference numeral 311 denotes a first moving frame for detecting the position of the correction lens L3, the first coil 312 for driving the first moving frame 311 in a plane orthogonal to the optical axis, and the position of the first moving frame 311. A flexible printed circuit board (FPC) 341 to which the hall element 313 is soldered is fixedly held. Reference numeral 321 denotes a second moving frame, which holds a magnet 322 for driving the second moving frame 321 in the direction perpendicular to the optical axis. The magnet 322 is magnetized with two poles in a direction perpendicular to the optical axis.

  Reference numeral 331 denotes a fixing member serving as a base of the image blur correction apparatus. The fixed member 331 holds a second coil 332 for driving the second moving frame 321, and a flexible printed circuit board (FPC) 341 to which a Hall element 333 for detecting the position of the second moving frame 321 is soldered is fixed. Has been. The FPC 341 is connected to the image blur correction device control unit 551 via a connector, and the camera lens control unit 552 that controls the image blur correction control unit 551 is information on the image blur detection unit 553, the image sensor 556, the camera operation unit 554, and the like. Judgment and control are appropriate.

  Reference numeral 351 denotes a first ball for supporting the first moving frame 311 so that it can roll with respect to the second moving frame 321. Reference numeral 361 denotes a second ball for supporting the second moving frame 321 in a rollable manner with respect to the fixed member 331. These balls move between the first moving frame 311 and the second moving frame 321 and between the second moving frame 321 and the fixed member by the contraction force of the tension spring 371 provided between the first moving frame 321 and the fixed member 331. It is held between 331. As a result, the first moving frame 311 and the second moving frame 321 can be moved in any plane perpendicular to the optical axis while the positions in the optical axis direction are restricted. Instead of urging by the tension spring 371, a urging yoke may be provided and clamped by an attractive force with the magnet 322 as described in Patent Document 1.

  Next, a method for driving the first moving frame 311 and the second moving frame 321 will be described. First, the first moving frame 311 moves by a so-called moving coil system in which a driving force is a magnetic force generated from the magnet 322 and a Lorentz force generated by energizing the first coil 312. In addition, as described above, the position detection of the first moving frame detects a change in magnetic force due to a positional shift between the Hall element 313 and the magnet 322. By sending this position signal to the image blur correction control unit 351 via the FPC 341 and feeding back to the coil 312 as a drive voltage, the first moving frame can move relative to the second moving frame.

  The second moving frame 321 moves by a so-called moving magnet method in which a reaction force between a magnetic force generated from the magnet 322 and a Lorentz force generated by energizing the second coil 332 is used as a driving force. In addition, the position detection of the second moving frame detects a change in magnetic force due to a positional shift between the Hall element 333 and the magnet 322. This position signal is sent to the image blur correction control unit 351 via the FPC 341 and fed back as a coil 332 drive voltage, whereby the second moving frame can move relative to the fixed member 331.

  Next, the amount of movement of the movable part of the image blur correction device will be described with reference to FIG. Assume that the linearity guarantee range of the outputs of the Hall elements 313 and 333 is Lmm, and the movement amount of the vibration-proof lens L3 is 2 × Lmm.

  FIGS. 7A and 7B are views of the image blur correction device as viewed from the front, and FIG. 7A shows a state where the image stabilizing lens L3 is held at the center. On the other hand, (b) shows a state where the vibration-proof lens is moved 2 × L mm. (C), (e) is the AA cross section of (a), (b) CC sectional drawing, respectively. When the anti-vibration lens L3 moves 2 × L mm, the second moving frame 321 moves L mm relative to the fixed member 331. At this time, since it is driven within the linearity guarantee range of the Hall element output, the position of the second moving frame 321 with respect to the fixed frame 331 can be detected with high accuracy.

  Subsequently, the first moving frame 311 moves L mm with respect to the second moving frame 321. At this time, since it is driven within the linearity guarantee range of the Hall element output, the position of the first moving frame 311 with respect to the second moving frame 321 can be detected with high accuracy. By moving as described above, it is possible to move 2 × L mm, and it is possible to detect the position of the image stabilizing lens L3 with high accuracy over the entire area.

  (D), (f) is the BB cross section of (a), (b) DD sectional drawing, respectively, has shown the rolling support part of the 1st ball | bowl 351 and the 2nd ball | bowl 361. FIG. When the anti-vibration lens L3 moves 2 × L mm, the second ball 371 sandwiched between the second moving frame 321 and the fixed member 331 rolls, so that the movement amount L of the second moving frame is L / 2 mm. Roll and move. Further, the first ball held between the first moving frame 311 and the second moving frame 321 moves L / 2 mm with respect to the second moving frame. However, since the movement amount of the second moving frame is added to the movement amount of the first ball relative to the fixed member, the movement amount is L + L / 2 = 1.5 × L mm.

  Next, the position detection accuracy according to the present invention will be described. As shown in FIG. 8, if position detection is performed in a range where the linearity can be ensured with only one Hall element exceeds Lmm, the position accuracy of the anti-vibration lens cannot be ensured because the linearity lowering portion is used. . Further, as shown in FIG. 2, when two Hall elements are used, the drive unit is increased in size. However, with the configuration shown above, when trying to detect the position of 2 × Lmm, it is difficult to keep the positional accuracy of the vibration-proof lens L3 high because it exceeds the linearity guarantee range. The position of the first moving frame 311 that holds the anti-vibration lens L3 is linear with respect to the second moving frame 321, and the position of the second moving frame 321 is such that the Hall element output with respect to the fixed member 331. Since it is linear, it is possible to ensure linearity in a wider range than the conventional position detection method using one Hall element.

  FIG. 7 briefly describes the space efficiency when the present invention is applied. As a premise of FIG. 9, it is assumed that the coil and the magnet overlap within the moving range of the coil so that the change in driving force is small within the stroke range.

  (A) and (d) are magnetic circuits in which two Hall elements are arranged as in Patent Document 3, arranged in a coil, and driven while ensuring linearity within a desired stroke range of 2 × Lmm. The configuration is shown. As described above, since two Hall elements are provided in the coil, the coil becomes larger in the direction perpendicular to the optical axis. In order to reduce the change in driving force over the entire stroke, it is desirable that the magnet overlaps the coil within a moving range of at least 2 × Lmm. It will become.

  (B), (e) shows the case where the configuration of the present invention described above is applied. First, the moving amount of each of the first moving frame and the second moving frame can be halved by setting the movable portion to the first and second two-stage configuration. Accordingly, when it is assumed that the coil and the magnet overlap each other within the movement range, the size of the magnet can be reduced by the amount of movement. Further, since the amount of movement per stage is Lmm that can ensure linearity, only one Hall element is required in the coil. Therefore, it is possible to greatly reduce the size of the drive unit by reducing the movement amount per stage.

  (C) shows the case where the space in the direction perpendicular to the optical axis is effectively used so that the clearance between the drive unit and the lens born by downsizing the drive unit in (f) is the same as (a) and (d). In the case where the present invention is applied with the same lens, the configuration in which the space is most effectively used is shown, and the size in the direction perpendicular to the optical axis can be reduced as compared with the configurations of (a) and (d). It is possible to reduce the size of the lens barrel in the direction perpendicular to the optical axis as well as the image blur correction device.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

L3 vibration-proof lens, 311 first moving frame, 312 first coil,
313 1st Hall element, 321 2nd moving frame, 322 magnet,
331 fixing member, 333 second hall element

Claims (7)

A first moving member holding a shake correction lens;
A second moving member that movably supports the first moving frame in a plane orthogonal to the optical axis;
A fixing member that movably supports the second moving frame in a plane orthogonal to the optical axis;
A biasing member that biases the first moving member and the second moving member against the base;
At least two drive means for moving the first moving member;
At least two driving means for moving the second moving member;
First position detecting means for detecting a relative position between the first moving member and the second moving member;
Second position detecting means for detecting a relative position between the second moving member and the fixed member;
Control means for controlling the positions of the first and second moving members based on the position information of the first and second position detecting means;
An image blur correction apparatus, wherein the first moving member is movable relative to the second moving member, and the second moving member is movable relative to the fixed member. The driving means includes
The second moving frame has a magnet;
The first moving frame has a first coil for driving the first moving frame,
A second coil for moving the second moving member to the fixed member;
2. The image blur correction apparatus according to claim 1, wherein the first moving member and the second moving member are moved by energizing the first coil and the second coil. The position detecting means includes
Magnetic detection means for detecting magnetism of a magnet provided on the first moving member and provided on the second moving member;
3. The image blur correction device according to claim 1, wherein the image blur correction device is configured by a magnetic detection unit that is provided on the fixed member and detects magnetism of a magnet provided on the second moving member. . Between the first moving member and the second moving member;
Between the second moving member and the fixed member,
Each having at least three balls,
The image blur correction apparatus according to claim 1, wherein the image blur correction apparatus is held by the urging unit. The biasing means is
The image blur correction device according to claim 1, wherein the image blur correction device is biased by an elastic member provided between the first moving member and the fixed member. The biasing means is
A magnetic attractive force acting between a yoke member provided in the first moving frame and a magnet provided in the second moving member;
The biasing force is exerted by a magnetic attraction force acting between a yoke member provided on the fixed member and a magnet provided on the second moving member. Image blur correction device. An optical apparatus having an optical system composed of a plurality of lens groups and an imaging device, comprising the image blur correction device according to claim 1.