JP2010197519A - Optical correction unit, lens barrel and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extend an area where linearity of output of a Hall element can be ensured without lowering driving force. <P>SOLUTION: The optical correction unit includes: a correction lens that corrects image blur caused by vibration; a movable member that holds the correction lens; a base member that constitutes a base of the unit; a supporting means that supports the movable member to freely translate and rotate on a plane nearly orthogonal to an optical axis of the correction lens relative to the base member; a position detection means that detects a position of the correction lens; and three driving means that move the movable member in a direction nearly orthogonal to the optical axis. The driving means has at least a coil mounted on a substrate fixed on the base member, and a magnet provided at a position where it is opposed to the coil in the movable member. The position detection means is provided on a surface of the substrate on a side where the coil is not mounted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical correction unit for correcting image blur that occurs during photographing, a lens barrel including the optical correction unit, and an imaging apparatus.

  In recent years, many cameras equipped with a camera shake correction function for correcting image blur due to camera shake in order to reduce image shake failure due to camera shake during shooting have been seen. As a means for realizing the camera shake correction function, the image forming optical system has a correction lens that can move in a plane perpendicular to the optical axis, and this correction lens is in a direction to cancel camera vibration caused by camera shake or the like. In-lens optical correction type that corrects image blur by driving and image blur at the image processing stage by comparing the multiple images temporarily stored in the buffer memory by narrowing the imaging area of the imager when shooting There is an electronic correction type that corrects. There is also an in-camera optical correction type that corrects image blur by driving the imager itself.

  However, with the electronic correction type, only a part of the imager is used at the time of shooting, so a high-definition image cannot be obtained, and it is not very effective for blur correction of still images that are often shot one by one. For this reason, single-lens reflex digital cameras are generally equipped with an optical correction type camera shake correction function.

  As a general structure of an optical correction type camera shake correction apparatus, for example, Patent Document 1 is known. In the invention disclosed in this patent document, the actuator is a fixed plate that is a fixed member fixed in the lens barrel, a moving frame that is a movable member supported to be movable with respect to the fixed plate, and It has a configuration having a parallel movement device provided with three steel balls which are spherical bodies supporting the moving frame.

  The parallel movement device includes a spherical magnet that is a spherical body adsorbing means for adsorbing the steel ball to the moving frame, and a steel ball receiver attached to the fixed plate so that the steel ball rolls smoothly between the fixed plate and the moving frame. And a steel ball receiver attached to the moving frame.

  Further, the actuator is arranged inside the three drive coils attached to the fixed plate, the three drive magnets attached to the moving frame at positions corresponding to the drive coils, and the respective drive coils. And a Hall element which is a position detecting means.

  The actuator effectively directs the magnetic force of the attracting yoke attached to the stationary plate and the driving magnet toward the stationary plate so that the moving frame is attracted to the stationary plate by the magnetic force of the driving magnet. And a back yoke attached to the back side of the driving magnet.

  The driving coil and the three driving magnets attached to the corresponding positions constitute driving means that can translate and rotate the moving frame with respect to the fixed plate. The drive magnet acts as an attracting magnet for attracting the moving frame to the fixed plate, and the attracting yoke acts as a magnetic body attracted by the attracting magnet.

  Further, in the invention disclosed in Patent Document 2, the blur correction device is configured in a biaxial direction (X-axis direction and Y-axis direction) perpendicular to each other with the movable lens frame holding the blur correction lens in a plane orthogonal to the optical axis. And two position detection devices that respectively detect the positions of the blur correction lens in the two-axis directions (X-axis direction and Y-axis direction). The X-axis direction VCM and position detection device are located on both sides of the shake correction lens, and the Y-axis direction VCM and position detection device are also located on both sides of the shake correction lens. Yes.

  Each of the two VCMs includes a coil, a magnet, and two yokes. The coil is fixed to the movable lens frame, and the magnet is fixed to the support portion of the base in a state of facing the coil. One yoke is a plate-like magnetic body and is disposed on the support portion. The other yoke is also a plate-like magnetic body, and is fixed at a position facing the coil in the lid portion attached to the end portion in the optical axis direction of the base portion.

  The two position detection devices each include a Hall element, two magnetic generation units, two yokes, and a flexible printed board. The two Hall elements are fixed to the movable lens frame. The first magnetism generating portion is fixed to the support portion of the base portion in a state facing the Hall element. The second magnetism generating portion is fixed to the base lid portion in a state facing the Hall element.

Each magnetism generator includes a first magnet, a second magnet, and a non-polar part. Each magnet is arranged so that different magnetic poles face each other with respect to the Hall element. The non-magnetic pole portion disposed between the first magnet and the second magnet is formed of a non-magnetic material such as a synthetic resin material or glass, or the first magnet and the second magnet are It is formed by separating.
JP 2007-086808 A JP 2008-045919 A

  In the above two patent documents, as a position detection means for detecting the position of the movable member (corresponding to the movable frame of Patent Document 1 and the movable lens frame of Patent Document 2), a Hall element which is a kind of magnetic sensor is used. Yes. This Hall element is an element that detects a magnetic flux density and outputs a voltage corresponding to the detected magnetic flux density. Therefore, as described in Patent Document 2, the output from the Hall element changes depending on the distance from the magnetic source that generates the magnetic flux density.

  The change in the Hall element output changes as schematically shown in FIG. 8 according to the distance (gap) between the Hall element and the magnetic source (magnet) under the same conditions. That is, when the gap in FIG. 8a is used as a reference, when the gap is reduced, the Hall element output is as shown in FIG. 8b. Conversely, when the gap is increased, the Hall element output is as shown in FIG. 8c. In these graphs, the horizontal axis represents the distance in the direction parallel to the magnet, and the vertical axis represents the magnetic flux density at that position.

  In the vicinity of the origin, the Hall element output exhibits good linearity (linearity) within a predetermined range as indicated by a broken line in the figure. In the area where the linearity of the magnetic flux density is secured (linearity securing area), it is possible to find a proportional relationship between the shift of the Hall element and the increase / decrease of the output, and this can be used to accurately position the movable member. Can be detected. When the linearity securing area is large, the movable range of the correction lens used for blur correction can be widened. Compared to FIG. 8a, this region is narrower in the state shown in FIG. 8b, and conversely, it is wider in the state shown in FIG. 8c. If the linearity securing area is wide, any range within that area can be used for shake correction, so that there is a margin in the assembly accuracy of the Hall element and magnet and the magnetizing accuracy of the magnet. On the contrary, as the linearity securing area becomes narrower, it becomes necessary to tighten tolerances of various precisions accordingly.

  In the invention disclosed in Patent Document 1, since the position detecting means is configured as shown in FIG. 5 in the document, the gap between the Hall element and the magnetic generation source (driving magnet) is small, and the Hall element output is reduced. The linearity securing area becomes narrow. As a result, as described above, there is a concern that the movable range of the image stabilization lens may be reduced and the assembly workability of the Hall element may be reduced.

  Further, since the adsorption yoke is provided on the back side of the substrate, it is necessary to keep the entire fixed plate away from the moving frame in order to secure the distance between the Hall element and the driving magnet. For this reason, there is a possibility that the driving force generated by the driving means is reduced and the entire apparatus is enlarged.

  Furthermore, since the Hall element is arranged inside the winding of the driving coil in this embodiment, the Hall element mounting area is necessary even if the shift amount of the image stabilization lens necessary for blur correction is small. Therefore, there is a limit to downsizing the drive coil. In addition, since the distance between the driving coil and the Hall element is short, the Hall element detects the minute magnetic flux density generated by the current in the coil, resulting in noise in the Hall element output.

  The invention disclosed in Patent Document 2 is intended to solve problems caused by the difference in gaps that are concerned in Patent Document 1 as described above. By adopting the configuration disclosed in this patent document, it is possible to prevent a decrease in position detection accuracy due to a gap difference, but it has the following problems.

  That is, in the structure of this patent document, it is necessary to provide two magnetism generators on both sides of the Hall element, which leads to an increase in weight and cost of the shake correction device. In addition, it is necessary to provide a region for arranging the second magnetism generation unit, which has not been conventionally required.

  In addition, since these two magnetism generating parts are made of permanent magnets, if they are arranged facing each other so as to sandwich the Hall element, an attractive force acts between the two magnetism generating parts by the mutual magnetic force. Therefore, high rigidity is required for the support portion and the lid portion of the base portion that fixes them. As a result of these, there is a risk of increasing the weight and size of the shake correction device, complicating the structure, and reducing the degree of freedom in design.

  Further, in this patent document, a position generating magnetism generating unit and a driving magnet are separately provided, and a configuration in which they are shared is not disclosed. Similarly, in this patent document, a so-called moving coil type blur correction device is disclosed, and there is no mention of application to a so-called moving magnet type.

  The present invention has been made in view of such a situation, and an object of the present invention is to expand an area where the linearity of the Hall element output can be secured with a simple structure without reducing the driving force.

  To achieve the above object, an optical correction unit embodying the present invention includes a correction lens that corrects image blur caused by vibration, a movable member that holds the correction lens, a base member that forms the base of the unit, A support means for supporting the movable member with respect to the base member so as to translate and rotate on a plane substantially orthogonal to the optical axis of the correction lens, a position detection means for detecting the position of the correction lens, and the movable member with the optical axis. Three driving means that move in a direction substantially orthogonal to the coil, and the driving means includes at least a coil mounted on a substrate fixed to the base member, and a magnet provided at a position facing the coil in the movable member. The position detection means is configured to be provided on the surface of the substrate where the coil is not mounted.

  Furthermore, the optical correction unit embodying the present invention is the above-described invention, wherein the substrate is a flexible printed circuit board on which electronic components can be mounted on both sides, and a through hole is provided in a region corresponding to the coil on the surface where the coil is not mounted. A reinforcing plate is arranged, and a position detecting means is mounted on a flexible printed circuit board exposed through a through hole.

  Further, a lens barrel embodying the present invention is configured to include the optical correction unit described in the above invention.

  Furthermore, an imaging apparatus embodying the present invention is configured to include the lens barrel described in the above invention.

  According to the optical correction unit, the lens barrel, and the imaging device that implement the present invention, it is possible to expand the region in which the linearity of the Hall element output can be ensured with a simple structure without reducing the driving force.

It is the perspective view which showed the external appearance of the optical correction unit which is one Embodiment of this invention. FIG. 2 is a developed perspective view of the optical correction unit shown in FIG. 1, and some members are indicated by broken lines for explanation. It is a top view of the optical correction unit shown in FIG. 1, and some members are shown with a broken line for description. It is the sectional view on the AA line shown in FIG. It is an expanded sectional view of a drive means, and is a figure for demonstrating the magnetic circuit formed in a drive means. 6A and 6B are diagrams for explaining the operation principle of the position detecting means, FIG. 6A is an explanatory diagram showing an outline of the configuration, and FIG. 6B is a graph for explaining the relationship between the position of the Hall element with respect to the magnet and the magnetic flux density. It is a block diagram which shows the concept of the blur correction control of the lens-barrel of this invention, and an imaging device. FIG. 8A is a graph for explaining a change in the Hall element output when the gap between the Hall element and the magnet is changed. FIG. 8A is a Hall element output in a reference gap, and FIG. 8B is a shorter gap than that in FIG. FIG. 8c shows the Hall element output when the gap is made longer than that of FIG. 8a.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment.

  First, the configuration of the optical correction unit of the present invention will be described. The optical correction unit 100 has a generally disc-shaped outer diameter as shown in FIGS. 1 and 2, and a correction lens 111 that corrects image blur caused by vibration applied to the unit, and a lens that holds the correction lens. A holding frame 112 (corresponding to the movable member described in the claims), a base member 121 serving as a base of the optical correction unit, and a circumference around the optical axis in a plane orthogonal to the optical axis of the correction lens 111 And three steel balls 131 which are sandwiched between the lens holding frame 112 and the base member 121 and support the lens holding frame, and a circuit board 122 fixed to the base member 121. Equivalent to the substrate described in the range).

  The lens holding frame 112 and the base member 121 are provided with a movable side steel ball receiving part 132 and a fixed side steel ball receiving part 133 at positions corresponding to the three steel balls 131, respectively. It is sandwiched between the receiving parts. Accordingly, the lens holding frame 112 can move smoothly with respect to the base member 121 in a plane orthogonal to the optical axis. In this embodiment, the movable-side steel ball receiver 132 and the fixed-side steel ball receiver 133 have a circular concave shape with the same radius, and the steel ball 131 is prevented from falling off by the concave wall surface. . In addition, the movable side steel ball receiving part 132, the fixed side steel ball receiving part 133, and the steel ball 131 constitute the support means described in the claims.

  The lens holding frame 112 includes a cylindrical portion 112a on which the correction lens 111 is caulked, a permanent magnet 113 (corresponding to a magnet described in claims), and a back yoke 114 (corresponding to a first yoke described in claims). ), And a flange portion 112b including a movable-side steel ball receiving portion 132. The back yoke 114 is fixed to the flange portion 112b by insert molding. The back yoke 114 is made of a soft magnetic metal, and the permanent magnet 113 is magnetically attracted to the back yoke 114 and held. In order to further increase the holding force between the permanent magnet 113 and the back yoke 114, it may be possible to interpose an adhesive means such as an adhesive or a double-sided adhesive tape between them. The cylindrical portion 112a of the lens holding frame 112 is further provided with a movable yoke 115 (corresponding to the second yoke described in the claims). The movable yoke 115 has a flange portion 112b of the cylindrical portion 112a. It is attached at a position facing the permanent magnet 113 at the end on the non-side.

  A generally annular circuit board 122 is disposed in a cylindrical space region surrounded by the movable yoke 115, the flange portion 112b, and the cylindrical portion 112a. The circuit board 122 is fixed to a plurality of bosses extending from the base member 121 with screws 123 so as not to interfere with various members attached to the lens holding frame 112. A coil 124 to which power is supplied from a power source (not shown) is mounted on the circuit board 122 and is fixed at a position facing the permanent magnet 113. In FIG. 2, a part of the coil 124 is indicated by a wavy line.

  The coil 124 fixed to the base member 121 side through the circuit board 122 is configured to be sandwiched between a movable yoke 115 and a permanent magnet 113 that can move in a direction orthogonal to the optical axis via the lens holding frame 112. Yes. As a result, a driving unit that generates a driving force for driving the lens holding frame 112 in a plane orthogonal to the optical axis is configured. This driving means corresponds to the driving means described in the claims. The driving of the lens holding frame 112 will be described in detail later.

  As shown in FIG. 3 and the like, the optical correction unit 100 of the present invention has three driving means, and these are spaced by 120 ° on a circumference centered on the optical axis in a plane perpendicular to the optical axis. Therefore, it is provided at a position where it does not interfere with the support means of the steel ball 131 described above. In the present embodiment, the adjacent drive means and support means are arranged with a 60 ° offset from the optical axis. Further, each coil 124 has a substantially rectangular shape, and is arranged so that its long side coincides with the tangential direction of the circumference centering on the optical axis.

  In this embodiment, the circuit board 122 on which the three coils 124 are mounted is a flexible printed circuit board 122a having circuit patterns formed on both sides thereof as shown in FIGS. Has been implemented. A reinforcing plate 122b for securing the strength of the flexible printed circuit board 122a is attached to the other surface by an adhesive means such as an adhesive or a double-sided adhesive tape. The reinforcing plate 122b has substantially the same shape as the flexible printed circuit board 122a. In addition to ensuring strength, the reinforcing printed circuit board 122a is improved in assembly workability by providing rigidity, and is generated from the driving means. The flexible printed circuit board 122a is deformed by the reaction force of the driving force, and has a role of preventing the driving unit and the position detecting unit from being displaced. The thickness of the reinforcing plate 122b can be freely determined as long as these roles can be fulfilled.

  As shown in FIGS. 3 and 4, the reinforcing plate 122b is provided with a through hole 122c at a location corresponding to the center of the winding of each coil 124, and the flexible printed circuit board is formed through the through hole 122c. Three Hall elements 125 are mounted on 122a. Therefore, the coil 124 is located on the surface facing the corresponding permanent magnet 113, and the Hall element 125 is located on the surface facing the corresponding movable yoke 115. Further, each of these Hall elements 125 is arranged such that the detection portion of the Hall element 125 is on the magnetic pole boundary line of the permanent magnet 113. In FIG. 3, the flexible printed circuit board 122a, the reinforcing plate 122b, and the movable yoke 115 are indicated by wavy lines.

  Since the Hall element 125 is located in a space sandwiched between the corresponding permanent magnet 113 and the movable yoke 115, the magnetic flux density from the permanent magnet 113 generated by the movement of the lens holding frame 112, which is a movable member. Detect changes. The position of the correction lens 111 at that time can be known from the outputs of the three Hall elements 125. The Hall element 125 and the permanent magnet 113 constitute position detecting means described in the claims. The principle of detecting the position of the Hall element 125 will be described in detail later.

  The arrangement of each member provided in the optical correction unit 100 described below will be described with reference to the state where the lens holding frame 112 is centered with respect to the base member 121. This centering state refers to a state in which the optical axis of the correction lens 111 and the central axis of the base member 121 coincide with each other, and the centers of the respective members of the driving means and the position detecting means are aligned in the optical axis direction. And

  The magnitude relationship in the plane direction perpendicular to the optical axis of each member of the driving means and the position detecting means in the centering state is as shown in FIGS. In the radial direction of the optical correction unit 100 having a generally disk shape, the movable yoke 115, the permanent magnet 113, and the back yoke 114 have substantially the same size, and the coil 124 is slightly smaller than them. With respect to the tangential direction, the size of the movable yoke 115 and the back yoke 114 is a size that fits between the inner diameter and the outer diameter of the winding of the coil 124, and the size of the permanent magnet 113 is the winding of the coil 124. It is slightly smaller than the inner diameter.

  A through hole 122c provided in the reinforcing plate 122b is sized to accommodate the Hall element 125. The through-hole 122c can be arbitrarily sized within the range in which the above-described reinforcing plate 122b can play a role. Therefore, the Hall element 125 can be freely selected to some extent without being influenced by its outer diameter. Is possible. Further, as compared with the case where the Hall element 125 is arranged inside the winding of the coil 124 as in the prior art, the outer diameter of the Hall element 125 does not prevent the coil 124 from being downsized.

  Here, the movable yoke 115 constituting the driving means will be described. As shown in FIGS. 2 to 4, the movable yoke 115 provided at the tip of the cylindrical portion 112 a of the lens holding frame 112 connects the three opposing portions 115 a provided at positions corresponding to the permanent magnet 113 and the coil 124. It is a flat integrated press part having a connecting part 115b. The facing portion 115 a has a shape similar to that of the corresponding permanent magnet 113, and its center is located on a straight line connecting the centers of other members in the centering state of the lens holding frame 112. The connecting portion 115b has a shape thinner than the facing portion 115a as long as both the strength and weight reduction of the entire movable yoke 115 can be achieved, and the movable yoke 115 is generally Y-shaped as a whole.

  The movable yoke 115 is made of a soft magnetic metal, so that a magnetic attractive force is generated between the movable yoke 115 and the permanent magnet 113 provided on the lens holding frame 112. The movable yoke 115 is attracted to the lens holding frame 112 using this suction force, and is positioned only by a plurality of cutout portions 115d corresponding to the positioning convex portions 115c provided at the tip of the cylindrical portion 112a. The movable yoke 115 may be more securely fixed by using an adhesive means such as an adhesive or a double-sided adhesive tape in addition to magnetic adsorption.

  At this time, if the movable yoke 115 is vigorously attracted by a strong magnetic attraction force, it may be erroneously removed from the positioning means. As a result, the movable yoke 115 comes into contact with the hall element 125, and the hall element 125 is destroyed. In order to avoid such a problem, the thickness of the hall element 125 may be made slightly thicker in advance than the height in the optical axis direction of the hall element 125 when mounted on the flexible printed circuit board 122a. With such a configuration, the movable yoke 115 comes into contact with the reinforcing plate 122b instead of the Hall element 125 in the above case, so that the Hall element 125 can be prevented from being destroyed.

  A region where the coil 124 overlaps with the permanent magnet 113 in the optical axis direction functions as a driving force generator that generates a force for driving the lens holding frame 112 with respect to the base member 121. According to the present embodiment, the long side portion of the coil 124 overlaps with the permanent magnet 113. Hereinafter, the principle of generating a driving force in the driving means of this embodiment will be briefly described.

  As shown in FIG. 5, the permanent magnet 113 fixed to the lens holding frame 112 is fixed by magnetic attraction to the back yoke 114 insert-molded on the lens holding frame 112 and the tip of the cylindrical portion 112 a of the lens holding frame 112. By being sandwiched between the movable yokes 115, the magnetic flux generated from each permanent magnet 113 is efficiently directed toward the yokes in a well-oriented direction with little leakage. Thereby, each driving means constitutes a magnetic circuit as written in FIG.

  As described above, the long side of the coil 124 mounted on the circuit board 122 is located in the magnetic circuit, and when this coil 124 is energized, Lorentz force acts on the electrons flowing in the coil 124, thereby holding the lens. The frame 112 is driven with respect to the base member 121. As described above, since the magnetic circuit in which the coil 124 is located is rectified with less leakage magnetic flux by the back yoke 114 and the movable yoke 115, the output of the generated driving force is higher than when the yoke is not used. In addition, the direction of the generated driving force follows the Fleming left-hand rule.

  In the present embodiment, as shown in FIG. 3, the three driving means described above are arranged at 120 ° intervals so that the long sides of the coils 124 face the tangential direction of the circumference centered on the optical axis. Therefore, the driving force of each driving means has three axes at 120 ° intervals in the radial direction of the circumference, and the intersection in the direction of generation of each driving force is located on the optical axis in the centering state. As described above, since the lens holding frame 112 is movable in a plane orthogonal to the optical axis by the support means, the lens holding frame 112 translates with respect to the base member 121 along the three drive axes. Is done. By appropriately combining the driving along these three axes, the lens holding frame 112 can be moved to an arbitrary position.

  Further, as shown in FIG. 4, the attracting magnet 141 is attached to each back yoke 114 of the lens holding frame 112 by magnetic attraction on the surface opposite to the surface on which the permanent magnet 113 is attached. . In order to further increase the holding force between the attracting magnet 141 and the permanent magnet 113, it may be possible to interpose an adhesive means such as an adhesive or a double-sided adhesive tape between them. Further, at the positions corresponding to the attracting magnets 141 on the back side of the base member 121, the attracting yokes 142 are fixed by an adhesive means such as an adhesive or a double-sided adhesive tape. Since the attracting yoke 142 is made of a soft magnetic metal like the movable yoke 115 fixed to the lens holding frame 112, the magnetic attracting force is also exerted between the attracting magnet 141 and the attracting yoke 142. Occurs. The lens holding frame 112 is urged toward the base member 121 by the attracting magnet 141 and the attracting yoke 142.

  Next, the principle of position detection using the Hall element 125 will be described with reference to FIG. The Hall element 125 is a kind of magnetic sensor that detects a magnetic flux density and outputs a voltage corresponding to the detected magnetic flux density. Consider a case where a detection magnet 126 is arranged in the vicinity of the Hall element 125 as shown in FIG.

  The detection magnet 126 has a structure in which two rectangular flat plate-shaped two-pole magnets are overlapped as shown in the figure, and the magnetization direction is made different so that the plane direction of the magnet is divided into two equal parts. In addition, the polarity is made different so that the thickness direction orthogonal to the plane direction is also divided into two equal parts. With such a configuration, magnetic fluxes that are opposite to each other in the vertical direction are generated at both ends of the detection magnet 126, and a higher magnetic flux density can be obtained than when the detection magnet 126 is composed of only one dipole magnet. It becomes like this. Two yokes 127 made of soft magnetic metal are disposed in the vertical direction of the detection magnet 126. Thereby, a magnetic circuit with little leakage magnetic flux can be comprised. The hall element 125 is located on the extension of the magnetic pole boundary between the south pole and the north pole in the planar direction of the magnet 126 for detection, and this state is used as a reference.

  FIG. 6B is a graph showing the magnetic flux density of the magnetic field formed by the detection magnet 126, where the horizontal axis represents the distance in the plane direction and the vertical axis represents the magnetic flux density. On the magnetic pole boundary line of the detection magnet 126, the magnetic flux density becomes zero. In the configuration of FIG. 6a, the Hall element 125 detects the magnetic flux density of the detection magnet 126 when moving in a direction perpendicular to the magnetic pole boundary of the detection magnet 126, and generates a voltage proportional to the magnetic flux density shown in the graph. Output.

  In the present embodiment, as described above, the Hall element 125 is mounted on the surface opposite to the side where the coil 124 is mounted. By adopting such a configuration, the distance between the coil 124 and the permanent magnet 113 is maintained while maintaining the distance between the coil 124 and the permanent magnet 113 as compared with a configuration in which the Hall element 125 is mounted inside the winding of the coil 124. The gap between them can be made large. Thereby, it becomes possible to widen the linearity securing region of the Hall element output without reducing the driving force from the driving means. As a result, it is possible to widen the movable range of the correction lens used for blur correction, and allowance is provided for the assembly accuracy of the Hall element and the magnet and the magnetization accuracy of the magnet.

  In the present embodiment, the detection magnet 126 described above also serves as the permanent magnet 113 that constitutes the driving means, and the magnetization of the permanent magnet 113 is the same as that of the detection magnet 126 described above. Thereby, compared with the case where two magnets are provided as separate members, an increase in weight can be suppressed and space can be used efficiently. Further, the movable yoke 115 and the back yoke 114 of this embodiment serve as the yoke 127 described above.

  FIG. 7 is a block diagram showing an embodiment of the lens barrel of the present invention provided with the optical correction unit 100 having the configuration and functions described above, and further comprises this lens barrel and a camera body. 1 shows a block diagram of a camera system. This camera system shows an embodiment of an imaging apparatus of the present invention.

  The camera system 200 includes a lens barrel 210 and a camera body 220. The lens barrel 210 has a substantially cylindrical shape and includes an imaging optical system 211 therein. A lens side mount (not shown) is provided at the rear end of the lens barrel 210. A camera-side mount (not shown) is provided on the front surface of the camera body 220, and the lens barrel 210 and the camera body 220 are detachably fixed by coupling both mounts.

  Inside the camera body 220 on the optical axis of the imaging optical system 211, an imaging element (CCD, CMOS, etc.) (not shown) that photoelectrically converts subject light is provided. Further, a display device (LCD, organic EL, etc.) (not shown) is provided on the back of the camera body 220, and the camera body 220 is provided with a slot for recording media. Thereby, the camera body 220 can record the image information obtained by the image sensor on the recording medium or display it on the display device.

  In the lens barrel 210, the optical correction unit 100 described above is further provided. The correction lens 111 of the optical correction unit 100 constitutes a part of the imaging optical system 211 of the lens barrel 210. The base member 121 of the optical correction unit 100 is fixed in the lens barrel 210 so that the optical axis of the correction lens 111 of the optical correction unit 100 in the centering state coincides with the optical axis of the imaging optical system. .

  The lens barrel 210 is provided with two gyro sensors 212 and detects the rotation of the camera system 200 in the pitch direction and the yaw direction. These gyro sensors 212 detect a change in camera posture from acceleration, angular velocity, or angular acceleration acting on the camera system 200 due to a shake or shake of the photographer's hand, and the detected camera posture information is a control amount in the CPU 221. The data is input to the calculation unit 221a.

  Further, as already described, the three Hall elements 125 constituting the position detection system in the optical correction unit 100 detect a change in magnetic flux accompanying the movement of the permanent magnet 113. From the outputs of the three Hall elements 125, the position of the correction lens 111 at that time can be known. The detected position information of the correction lens 111 is also input to the control amount calculation unit 221 a in the CPU 221.

  The control amount calculation unit 221a in the CPU 221 compares the input camera posture information and the correction lens position information, and calculates a control amount necessary for blur correction. The calculated control amount is sent to the drive control unit 221b in the CPU 221.

  The drive control unit 221b calculates the drive amount and drive direction of the correction lens 111 necessary for correcting the shake amount based on the calculated control amount, and appropriately determines the amount of current flowing through the coil 124 of each drive unit. To be controlled.

  In the above-described embodiment, the circuit board 122 on which the coil 124 is mounted is the flexible printed circuit board 122a on which electronic components can be mounted on both sides, and the Hall element 125 and the reinforcement are provided on the surface opposite to the side on which the coil 124 is mounted. However, even if the flexible printed circuit board 122a is a thin double-sided hard circuit board and the reinforcing board 122b is not provided, the effects of the present invention can be exhibited.

  In addition, the camera system 200 in which the lens barrel 210 having the optical correction unit 100 as the lens barrel 210 and the camera barrel 220 is coupled to the camera body 220 has been described as an embodiment of the present invention. However, various arithmetic units for performing blur correction are provided. By disposing the lens in the lens barrel, it is possible to perform blur correction only with the lens barrel.

  Furthermore, although the camera system 200 has been described as one embodiment of the imaging apparatus of the present invention, the present invention is not limited to this, and can be applied to, for example, a video camera or a compact digital camera.

  As described above, according to the optical correction unit, the lens barrel, and the imaging device according to the present invention, the area in which the linearity of the Hall element output can be secured with a simple structure without reducing the driving force is expanded. It becomes possible.

DESCRIPTION OF SYMBOLS 100 Optical correction unit 111 Correction lens 112 Lens holding frame 113 Permanent magnet 114 Back yoke 115 Movable yoke 121 Base member 122 Circuit board 122a Flexible printed circuit board 122b Reinforcement board 122c Through hole 124 Coil 125 Hall element 131 Steel ball 141 Adsorption magnet 142 Adsorption Yoke 200 Camera system 210 Lens barrel 220 Camera body 211 Imaging optical system 212 Gyro sensor 221 CPU
221a Control amount calculation unit 221b Drive control unit

Claims (7)

  In an optical correction unit that performs shake correction by driving a correction lens that corrects image blur caused by vibration on a plane substantially orthogonal to the optical axis of the correction lens by the drive unit, the drive unit generates magnetic flux. A magnet and a coil provided at a position facing the magnet and generating a driving force by interaction with the magnetic flux of the magnet, and the position of the correction lens on the back surface of the substrate on which the coil is mounted An optical correction unit provided with position detection means for detecting A correction lens for correcting image blur caused by vibration;
A movable member holding the correction lens;
A base member constituting the base of the unit;
Support means for supporting the movable member with respect to the base member so as to translate and rotate on a plane substantially orthogonal to the optical axis of the correction lens;
Position detecting means for detecting the position of the correction lens;
Three driving means for moving the movable member in a direction substantially perpendicular to the optical axis;
In an optical correction unit comprising:
The driving means is at least
A coil mounted on a substrate fixed to the base member;
In the movable member, a magnet provided at a position facing the coil;
Have
The optical correction unit according to claim 1, wherein the position detection unit is provided on a surface of the substrate where the coil is not mounted.   The board is a flexible printed board on which the coil is mounted, and a reinforcing plate is disposed on a surface of the flexible printed board on which the coil is not mounted, and the reinforcing plate is a region corresponding to the coil. The optical correction unit according to claim 2, wherein a through hole is provided, and the position detection unit is mounted on the flexible printed circuit board exposed through the through hole.   A first yoke provided on the movable member and fixed to a surface of the magnet that does not face the coil, and a second yoke that is also provided on the movable member and fixed at a position facing the position detecting means. A yoke, and the position detecting means, the coil, and the magnet are arranged in a space region between the first yoke and the second yoke in a direction parallel to the optical axis. The optical correction unit according to claim 2, wherein:   5. The optical correction according to claim 2, wherein the position detecting means is a Hall element that detects a position of the movable member with respect to the base member by detecting a magnetic flux density of the magnet. unit.   A lens barrel comprising the optical correction unit according to claim 2.   An imaging apparatus comprising the lens barrel according to claim 5.

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