JP2011253149A - Lens barrel and optical device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel that effectively prevents a magnet from falling from a fixing frame due to a shock while avoiding use of a larger vibration-proof unit, and allows production with a fewer man-hours.SOLUTION: The lens barrel comprises: a shift lens barrel that holds a lens and shifts in a plane perpendicular to an optical axis; a fixing frame that supports the shift lens barrel so as to allow the shift lens barrel to shift in the plane perpendicular to the optical axis while sandwiching the same in the optical axis; and driving means that drives the shift lens barrel in the plane perpendicular to the optical axis. The driving means has an air core coil and a drive magnet. The fixing frame is provided with a drop-off prevention member which is disposed through an air-core of the coil from a position opposite to the drive magnet. The drop-off prevention member comes into contact with the drive magnet just before the drive magnet is drop off from a member to which the drive magnet is attached.

Description

  The present invention relates to a lens barrel and an optical apparatus having the same. In particular, a video camera having a function of driving a moving frame (shift barrel) holding a lens group for correcting image blur so as to have a component perpendicular to the optical axis in order to correct image blur caused by camera shake, etc., digital It is suitable for optical devices such as a still camera and a TV camera.

  In an optical apparatus (imaging device) such as a digital still camera, an image blur correction device that detects a camera shake of a photographer and cancels a blur (image blur) of a captured image is used. In this image blur correction apparatus, a moving frame (shift barrel) holding a lens group for image blur correction is driven in the pitch direction (vertical direction) and yaw direction (lateral direction) in a plane perpendicular to the optical axis. Yes. A driving coil, a magnet, and a yoke are used as driving means at this time, and the shift barrel is driven in the pitch direction and the yaw direction by these driving means.

  In an optical apparatus having such a drive mechanism, the magnet and the yoke may be detached from the lens barrel only by magnetic attraction when the optical apparatus is dropped. For this reason, there has been known a lens barrel in which the magnet and the yoke are prevented from falling off from the lens barrel in response to an external impact (Patent Documents 1 and 2).

  In the image blur correction device of Patent Document 1, the magnet and the yoke are held from one side in the optical axis direction with respect to the fixed portion of the fixed frame, and the yoke is inserted from the other side in the optical axis direction. Inserting. As a result, the fixed frame is fixed to the fixed frame by being attracted by the attractive force acting on the magnet and the yoke.

  In the image blur correction device of Patent Document 2, in order to improve the reliability of the drop impact, the drop strength is improved by providing a concave shape on one side of the back yoke and bonding it to the fixed frame.

JP 2003-57707 A JP 2006-235141 A

  In the image blur correction device disclosed in Patent Document 1, when an impact is applied from the outside such as a drop, one or both of them may come off if the attractive force is not sufficient with respect to the weight of the magnet or yoke. In the image blur correction device of Patent Document 2, since one side of the back yoke has a concave shape and is adhered to the fixed frame, the number of work steps tends to increase, and the manufacturing tends to take time.

  On the other hand, in recent years, there is a strong demand for downsizing the entire digital still camera. For this reason, there is a demand for the vibration isolation unit that the magnet and the yoke are not detached from the lens barrel in the event of a sudden impact such as dropping, and that it is as small as possible. As the vibration isolation unit increases in size, the lens barrel also increases in size, making it difficult to reduce the size of the optical device.

  It is an object of the present invention to provide a lens barrel that can reduce the number of work steps and effectively reduce the possibility of a magnet falling off a fixed frame due to an impact without increasing the size of a vibration isolation unit. .

  The lens barrel of the present invention is a shift barrel that holds a lens and moves in a plane perpendicular to the optical axis, and is opposed to the shift barrel in a plane perpendicular to the optical axis from the optical axis direction. A fixed frame that is sandwiched and supported, driving means for driving the shift barrel in a plane perpendicular to the optical axis, the driving means has an air-core coil and a drive magnet, A drop-off prevention member disposed from the position facing the drive magnet through the air core of the coil is provided, and the drop-off prevention member is a member to which the drive magnet is attached. It is characterized in that it comes into contact with the drive magnet when it comes off.

  According to the present invention, it is possible to obtain a lens barrel that can reduce the number of work steps and effectively reduce the possibility of the magnet falling off from the fixed frame due to an impact without increasing the size of the vibration isolation unit.

1 is an exploded perspective view of a vibration isolating unit that is an embodiment of the present invention. Sectional drawing of the lens apparatus carrying the anti-vibration unit of Example 1 2 is an exploded perspective view of FIG. 1 is an exploded perspective view of a vibration isolation unit of Embodiment 1. FIG. Sectional drawing of the magnet and yoke fixing | fixed part of the vibration isolator of Example 1 Sectional drawing of the magnet and yoke fixing | fixed part of the vibration isolator of Example 1 Front view of the drop-off prevention part of the vibration isolation unit of Embodiment 1 Sectional drawing of the vibration isolator unit of Example 1 Sectional drawing of the fall prevention part of the vibration isolator unit of Example 2

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The first embodiment of the lens barrel of the present invention has a shift barrel (correction lens frame) 101 that holds the lens L4A and moves in a plane orthogonal to the optical axis. The shift barrel 101 includes a base barrel 102 that supports the shift barrel 101 so as to be movable in a plane orthogonal to the optical axis, and is opposed to the optical axis, and a fixed frame including a cover member 115. The cover member 115 is fixed to the base barrel 102 with screws. Drive means for driving the shift barrel 101 in a plane orthogonal to the optical axis is provided. The driving means includes an air-core type coil 105P, a pair of drive magnets 103P and 106P facing in the optical axis direction, and a pair of drive yokes 104P and 107P facing in the optical axis direction. The coil 105P is provided in the shift barrel 101, and the drive magnet 103P and the drive yoke 104P constitute a magnetic circuit and are provided in the base barrel 102.

  The drive magnet 106P and the drive yoke 107P are provided on the cover member 115, and the coil 105P provided on the shift barrel 101 is located between the drive magnets 103P and 106P. The cover member 115 is provided with a drop-off preventing member 115a disposed so as to pass through the inside of the coil provided in the shift lens barrel 101 from a position facing the drive magnet 103P provided in the base lens barrel 102. When the drive magnet 103P is about to be detached from the drive magnet 104P (member), the drop-off prevention member 115a is in contact with the drive magnet 103P to prevent it from coming off from the drive magnet 104P. FIG. 1 is an exploded perspective view of a vibration isolation unit according to an embodiment of a lens barrel of the present invention.

[Example 1]
2 and 3 are schematic configuration diagrams of the lens barrel portion when the lens barrel that is Embodiment 1 of the present invention is applied to a video camera (optical apparatus). Inside the lens barrel, in order from the subject side, a variable power optical system (zoom) as a photographic optical system composed of five lens units of a lens group having positive, negative, positive, negative, and positive refractive powers. Lens). In the following description, the subject side may be referred to as the front side and the imaging element side may be referred to as the rear side. In these drawings, in order from the subject side (left side of the figure), L1 is a fixed first lens unit, and L2 and L3 are second and third lens units that move in the optical axis direction and perform zooming. is there. L4 is a fourth lens unit (correction lens) that corrects image touch that occurs when the zoom lens vibrates by moving in a direction orthogonal to the optical axis, and L5 is a fifth lens that performs focusing by moving in the optical axis direction Is a unit.

  Reference numeral 1 denotes a fixed front lens barrel that holds the first lens unit L1. Three cam followers 1a integrally attached to the outer periphery of the front lens barrel 1 at approximately 120 degrees equally in three through-hole portions 12a formed at approximately 120 degrees equally around the fixed barrel 12 Are engaged. Engagement of the three cam followers 1a provided in the front lens barrel 1 and the three through-hole portions 12a of the fixed barrel 12, and the outer diameter 1b of the front lens barrel 1 and the inner diameter portion 12b of the fixed barrel 12 The first lens unit L1 is positioned and held by the fitting.

  Reference numeral 2 denotes a second moving frame that holds the second lens unit L2, and moves during zooming. Reference numeral 3 denotes a third moving frame that holds the third lens unit L3 and moves during zooming. Reference numeral 4 denotes an anti-vibration unit (shift unit) that holds the fourth lens unit L4 so as to be movable in a direction perpendicular to the optical axis. The vibration isolation unit 4 is supported so as to be movable in a plane perpendicular to the optical axis with respect to the fixed barrel 12.

  Reference numeral 5 denotes a fifth moving frame that holds the fifth lens unit L5. Reference numeral 6 denotes a light amount adjustment unit (light amount adjustment device) that adjusts the amount of light reaching an image pickup device (to be described later) that converts an optical image formed by light that has entered the imaging optical system and passed through the aperture opening into an electrical signal. Reference numeral 7 denotes an ND unit that has an ND filter and manually switches the exposure in four stages. The ND unit 7 is fixed to the rear barrel 13 without being operated in the optical axis direction. Reference numeral 10 denotes an image sensor holding frame to which an image sensor 8 for converting an optical image formed by light passing through a diaphragm aperture such as a CCD sensor or a CMOS sensor into an electric signal and an optical filter such as an infrared cut / low pass filter 9 are attached. It is. The imaging element 8 has a function of a magnification unit that moves in the optical axis direction and performs magnification (zooming) while performing synchronization control with the second and third lens units L2 and L3.

  Reference numeral 11 denotes an image sensor electrical wiring (image sensor FPC (flexible printed circuit board)), which inputs and outputs electrical signals to the image sensor 8 held in the image sensor holding frame 10. The rear cover 14 is positioned and fixed to the rear barrel 13. Two guide bars 15 and 16 are fixed between the rear barrel 13 and the rear cover 14. The imaging element holding frame 10 is guided (moved) in the optical axis direction by a sleeve portion 10a provided on the imaging element holding frame 10 being movably engaged with the guide bar 15. Further, the U groove 10 b provided in the image sensor holding frame 10 is movably engaged with the guide bar 16 to prevent the image sensor holding frame 10 from rotating around the guide bar 15. The image sensor FPC 11 is arranged in a range between an inner wall formed by the rear barrel 13 and the rear cover 14 and an outer wall of the image sensor holding frame 10 so that the image sensor holding frame 10 can be moved in the optical axis direction.

  Reference numeral 17 denotes a slider (contact member) which is formed by joining a magnet and a friction material and which is positioned and fixed to the rear barrel 13. The image sensor holding frame 10 is fixedly positioned with a vibrator 18 constituted by an electro-mechanical energy conversion element and a plate-like elastic member whose vibration is excited by the electro-mechanical energy conversion element.

  Here, the elastic member of the vibrator 18 is a ferromagnetic body. When the ferromagnetic body attracts the magnet of the slider 17, two places in the optical axis direction on the pressure contact surface of the friction material of the slider 17 and the elastic member of the vibrator 18. The pressure contact surface formed on the surface is pressed. In the vibration type linear actuator constituted by the slider 17 and the vibrator 18, two frequency signals (pulse signals or alternating signals) having different phases are input to the electro-mechanical energy conversion element via a flexible wiring board (not shown). Is done. Thereby, a substantially elliptical motion is generated on the pressure contact surface of the vibrator 18, and a driving force in the optical axis direction is generated on the pressure contact surface of the slider 17. The ND base 7a is positioned and fixed to the rear lens barrel 13, and two guide bars 19 and 20 are fixed between the rear lens barrel 13 and the ND base 7a.

  A sleeve portion 5 a provided in the fifth moving frame 5 is movably engaged with the guide bar 19 and guided in the optical axis direction, and a U groove portion 5 b provided in the fifth moving frame 5 is provided in the guide bar 20. It engages so that it can move and prevents rotation of the fifth moving frame 5 around the guide bar 19. Reference numeral 21 denotes a slider (contact member) that is positioned and fixed to a rear barrel 13 constituted by joining a magnet and a friction material. A vibrator (not shown) composed of an electro-mechanical energy conversion element and a plate-like elastic member whose vibration is excited by the electro-mechanical energy conversion element is positioned and fixed to the fifth moving frame 5. Here, the elastic member of the vibrator is a ferromagnetic body, and the ferromagnetic body attracts the magnet of the slider 21 to form the friction material pressure contact surface of the slider 21 and the elastic member of the vibrator at two locations in the optical axis direction. The pressed contact surface is pressed. In the vibration type linear actuator composed of the slider 21 and the vibrator, two frequency signals (pulse signals or alternating signals) having different phases are input to the electro-mechanical energy conversion element via a flexible wiring board (not shown). The Thereby, a substantially elliptical motion is generated on the pressure contact surface of the vibrator, and a driving force in the optical axis direction is generated on the pressure contact surface of the slider 21.

  Next, the configuration of the image stabilization unit (shift unit) 4 will be described in detail with reference to FIGS. 1, 4, 5, 6, 7, and 8. FIG. 1 is an exploded perspective view of the image stabilization unit 4 when viewed from the front side (object side). FIG. 4 is an exploded perspective view of the image stabilization unit 4 as viewed from the rear side (image plane side). FIG. 5 is a cross-sectional view of the magnet and yoke fixing portion of the base barrel 102. FIG. 6 is a cross-sectional view of the magnet and yoke fixing portion of the cover member 115. FIG. 7 is a front view of the drop-off prevention unit. FIG. 8 is a cross-sectional view of the vibration isolation unit.

  Reference numeral 101 denotes a shift lens barrel as a correction lens frame that holds a shake correction lens L4A as a correction lens (lens) for image blur correction and is movably held in a plane orthogonal to the optical axis. Reference numeral 102 denotes a base barrel that constitutes a part of the fixed frame of the image stabilizing unit 4. L4B is a fixed lens that constitutes the fourth lens unit L4 together with the blur correction lens L4A. 109a, 109b, 109c are first balls. The first balls 109a, 109b, and 109c may be made of a hard material such as SUS440C or ceramic that has good shape accuracy and surface finish. In particular, ceramic is a non-magnetic material, and is not attracted to the magnet, so that it is not affected by the surrounding magnetism and is preferable.

  The three balls 109a to 109c are arranged in rectangular recesses 102a and 102b102c formed on the base barrel 102 and having a flat bottom surface. The inner side surfaces of the recesses 102a, 102b, and 102c limit the movement range of the first balls 109a, 109b, and 109c. Further, the first balls 109 a to 109 c are in contact with the flat portions 101 a, 101 b, 101 c formed on the shift barrel 101.

  Next, suppression of rotation of the shift barrel 101 around the optical axis (hereinafter simply referred to as roll) will be described. Reference numeral 110 denotes a guide member. Reference numeral 111 denotes a roll prevention member disposed between the guide member 110 and the shift barrel 101. Reference numerals 112a, 112b, and 112c denote second balls. The second balls 112a to 112c are disposed in the first guide groove portions 111a, 111b, and 111c formed in the roll preventing member 111. The second balls 112a to 112c are in contact with the long holes 110b and 110c formed in the guide member 110 or the flat portion 110a, respectively.

  The first guide groove portions 111a to 111c and the long holes 110b and 110c are formed so as to extend in the direction of arrow A in the figure, and the guide member 110 and the roll prevention member 111 roll the second balls 112a to 112c. However, relative movement is possible in the direction of arrow A. Reference numerals 113a, 113b, and 113c denote third balls. The third balls 113a to 113c are disposed in the second guide groove portions 111d, 111e, 111f formed in the roll preventing member 111 and the third guide groove portions 101d, 101e, 101f formed in the shift barrel 101. Yes.

  The second guide groove portions 111d to 111f and the third guide groove portions 101d to 101f are formed to extend in the direction of arrow B in the drawing. The roll prevention member 111 and the shift barrel 101 are relatively movable in the direction of arrow B while rolling the third balls 113a to 113c. In this embodiment, the arrow A direction and the arrow B direction in FIG. 1 form an angle of 45 degrees with respect to the pitch direction and the yaw direction, respectively.

  Reference numerals 114 a and 114 b denote guide springs that urge the guide member 110 toward the roll prevention member 111 and the shift barrel 101 in the optical axis direction. Reference numeral 115 denotes a cover member that is positioned with respect to the base barrel 102 and is fixed by screws. The base barrel 102 and the cover member 115 constitute a fixed frame. The guide member 110 is positioned in the plane orthogonal to the optical axis by inserting the positioning pins 115d and 115e provided in the cover member 115 into the positioning hole 110d provided in the guide member 110 and the anti-rotation oblong hole 110e, respectively. The

  The guide springs 114a and 114b are compression coil springs. One end of the guide springs 114a and 114b is in contact with the root portions of the positioning pins 115d and 115e, and the other end is in contact with the guide member 110, so that the guide member 110 is attached to the shift barrel 101. Rush. The first balls 109a to 109c, the second balls 112a to 112c, and the third balls 113a to 113c are arranged so that the centers of gravity of the triangles having three balls as vertices are substantially equal.

  The resultant force of the urging forces of the guide springs 114a and 114b acts at a position substantially equal to the center of gravity of the three triangles formed by the first balls 109a to 109c, the second balls 112a to 112c, and the third balls 113a to 113c, respectively. . As a result, the forces applied to the nine balls are substantially equal. Reference numerals 103p and 106p denote drive magnets as driving means in the pitch direction, which are respectively arranged before and after the coil 105p provided in the shift barrel 101 (in the optical axis direction). As shown in FIG. 5, the S pole and the N pole are magnetized so as to be in opposite positions in the optical axis direction in each half of the direction orthogonal to the optical axis. Z is a neutral zone that is not magnetized.

  Reference numerals 104p and 107p denote drive yokes disposed on the back surfaces of the drive magnets 103p and 106p, respectively, and attached by magnetic attraction. The drive magnet 103p and the drive yoke 104p are provided on the base barrel 102. The drive magnet 106p and the drive yoke 107p are provided on the cover member 115. Reference numeral 105 p denotes an air core type coil having an air core portion, which is provided in the shift barrel 101. Between the drive magnets 103p and 106p, it arrange | positions so that two magnetic poles arrange | positioned at the upper and lower sides of the drive magnets 103p and 106p may be opposed. That is, the two drive magnets 103p and 106p are provided facing each other in the optical axis direction with the air-core type coil 105p interposed therebetween. A magnetic circuit is formed by the drive magnets 103p (103y) (106p) and the drive yokes 104p (104y) (107p).

  When the coil 105p is energized, the gap constraint in the magnetic circuit (103p, 104p) and the magnetic flux generated by the coil 105p magnetically interfere to generate a so-called Lorentz force. As a result, a driving force is applied to the shift barrel 101, and the shift barrel 101 is driven in the pitch direction. That is, the drive actuators 104p and 107p, the drive magnets 103p and 106p, and the coil 105p constitute a first actuator that moves the shift barrel 101 in a pitch direction (vertical direction) orthogonal to the optical axis.

  The width in the pitch direction of the inner periphery of the coil 105p (the width of the air core portion) is such that the neutral zone is not applied when driving to the end so that the thrust does not drop even when driven to the end. Note that the suffix p of each symbol indicates a component for correcting image blur due to rotational shake in the pitch direction. On the other hand, a subscript is attached to a component for correcting image blur due to rotational shake in the yaw direction (a direction perpendicular to the optical axis and in the horizontal direction). The drive configuration in the yaw direction is the same as the drive configuration in the pitch direction. In addition, regarding the direction orthogonal to the optical axis (or in the plane orthogonal to the optical axis) which is the moving direction of the shift barrel 101 and other members (or in the plane orthogonal to the optical axis), “orthogonal” is, of course, completely orthogonal to the optical axis. This includes the case of deviation from perfect orthogonality within the tolerance range (when it can be regarded as orthogonal).

  The drive yokes 104y and 107y, the drive magnets 103y and 106y, and the coil 105y constitute a second actuator that moves the shift barrel 101 in the yaw direction orthogonal to the optical axis. The width of the inner periphery of the coil 105y in the yaw direction is such that it does not reach the neutral zone when driven to the end so that the thrust does not drop even when driven to the end.

  Next, a method for fixing the drive magnet and the drive yoke will be described. As shown in FIG. 5, the drive magnets 103p and 103y and the drive yokes 104p and 104y are inserted from the front and rear (in the optical axis direction) of the base barrel 102, respectively. Then, it is regulated in the optical axis direction by positioning portions 102d and 102e provided in the base barrel 102, and is fixed to the base barrel 102 by mutual attractive force.

  In the present embodiment, the drive magnets 103p and 103y and the drive yokes 104p and 104y are inserted from the front and rear of the base barrel 102, but may be inserted from the rear in an attracted state.

  The drive yokes 107p and 107y and the drive magnets 106p and 106y are put in the cover member 115 in the attracted state in the direction of the arrow in FIG. 6, and are positioned by the positioning portion 115b. The drive magnets 106p and 106y are fixed to the cover member 115 by an attractive force with the drive magnets 103p and 103y provided on the base barrel 102. 116 is screwed to the cover member by a pressing metal plate of a shift FPC (not shown), and also serves to prevent the drive magnets 106p and 106y and the drive yokes 107p and 107y from falling off from the cover member 115. Reference numeral 115 a denotes a drop-off preventing portion provided on the cover member 115. The drop-off prevention part 115a is formed of a plate-like or bar-like protrusion. The drop-off prevention unit 115a prevents the drive magnets 103p and 103y from being detached from the member (drive yoke) 104p. In other words, the drop prevention portion 115a is provided at a distance from the drive magnet 103p so that the drive magnet 103p does not fall off the member (drive yoke 104p).

  As shown in FIG. 7, the longitudinal width of the drop-off preventing portion 115 a is larger than the longitudinal direction of the drive magnets 103 p and 103 y provided on the base member 102 and the drive magnets 106 p and 106 y provided on the cover member 115. The drop-off prevention portion 115a is integrated with the side of the holding portion 115ab of the drive magnet 106p of the cover member 115. The width in the direction orthogonal to the optical axis of the drop-off prevention portion 115a is such a size as to include the width of the neutral zone Z of the drive magnets 103p, 103y, 106p, and 106y. The drop-off prevention unit 115a is disposed in the direction perpendicular to the optical axis, passes through the inside of the coils 105p and 105y provided in the shift barrel 101, and faces the drive magnets 103p and 103y. The drop-off prevention unit 115a is not in contact with the drive magnets 103p and 103y during normal shooting.

  The thickness of the drive magnets 103p and 103y is 1 to 4 mm. The distance between the drop-off prevention unit 115a and the magnet 103p is as follows. The distance in the optical axis direction between the drop-off prevention unit 115a and the magnet 103p is set to 35 μm to 173 μm. The drive magnet 103p and the drop-off prevention portion 115a have a clearance in the optical axis direction so as not to be double-fitted. As the following parts vary within the tolerance, the clearance in the optical axis direction also changes. The tolerance of the thickness of the drive magnet 103p is preferably ± 20 μm to 100 μm. The tolerance of the receiving surface of the drive magnet 103p of the fixed frame (101, 115) is preferably ± 20 μm to 100 μm. The tolerance of the length dimension in the optical axis direction of the drop-off preventing portion 115a is preferably ± 20 μm to 100 μm.

  The square mean of these tolerances is calculated to be ± 35 μm to 173 μm. In order to prevent the drive magnet 103p and the drop-off prevention part 115a from coming into contact with each other even when the tolerances vary as described above, the clearance in the optical axis direction between the drive magnet 103p and the drop-off prevention part 115a is set to 35 μm to 173 μm. Yes. An external impact is applied to the shift unit (anti-vibration unit) 4 so that the drive magnets 103p and 103y provided on the base barrel 102 are likely to be detached from the base barrel 102. At this time, the drive magnets 103p and 103y abut against a drop-off preventing portion 115a provided on the cover member 115. The drop-off prevention member 115a serves as a stopper in the optical axis direction, and prevents the drive magnets 103p and 103y from coming off the base barrel 102.

  Although the preferable clearance in the optical axis direction between the drive magnet 103p and the drop-off preventing portion 115a has been described above, it is not particularly limited thereto. The idea of the drop-off prevention unit is that the drive magnet and the drive yoke can be magnetically attracted again by the contact with the drop-off prevention unit when the drive magnet is about to come off from the drive yoke, thereby preventing the drop off. Therefore, even if the drive magnet is detached from the drive yoke, the clearance in the optical axis direction between the drive magnet and the drop-off prevention part is set so that the attracted state can be recovered again by the magnetic attractive force with the drive yoke. It ’s fine.

  In this embodiment, the drive magnet and the drop-off prevention part are provided with a clearance in the optical axis direction so as not to be double-fitted. You may make a part contact. The drop-off prevention part 115a passes through the air core parts of the air core type coils 105p and 105y provided in the shift barrel 101, which is an originally vacant space, so that the vibration isolation unit 4 does not increase in size. Furthermore, since the width of the drop-off prevention part 115a in the direction perpendicular to the optical axis is such that it includes the width of the neutral zone Z of the drive magnets 103p, 103y, 106p, 106y, the coil does not increase in size. In other words, the drive magnets 103p and 103y are prevented from falling off the base barrel 102 without increasing the size of the shift unit 4. Although the drop-off preventing portion 115a may be separated from the cover member 15, in this embodiment, since it is formed integrally with the cover member 115, the manufacturing is facilitated without increasing the number of work steps.

  Next, a configuration for detecting the position of the shift barrel 101 in a plane orthogonal to the optical axis will be described. A hall sensor (hall element) 120 provided in the base barrel 102 converts the magnetic flux density into an electrical signal and is fixed by soldering to an unillustrated FPC. The hall sensor 120 is press-fitted into the base barrel 102 and is fixed to the base barrel 102 by being pressed by a sensor pressing plate 117. Sensor magnets 121p and 121y and sensor yokes 122p and 122y fixed to the shift lens barrel 101 are arranged at positions facing the Hall element 120. For this reason, when the shift barrel 101 is driven in the vertical or horizontal direction, the magnetic flux density detected by the Hall element 120 changes. By detecting this change in magnetic flux density as an electrical signal from the Hall element 120 by appropriate signal processing, it is possible to detect the position in the direction perpendicular to the optical axis of the shift barrel 101. Reference numeral 118 denotes an FPC guide for guiding an FPC of a diaphragm unit (not shown) to be brought out behind the vibration isolation unit, and is formed separately from the base barrel 102 and fixed to the base barrel 102 with screws. .

  Embodiment 2 of the lens barrel of the present invention will be described. The lens barrel of the second embodiment includes a shift barrel (correction lens frame) 201 that holds the lens L4A and moves in a plane orthogonal to the optical axis. The shift barrel 201 includes a base barrel 202 that supports the shift barrel 201 so as to be movable in a plane perpendicular to the optical axis and sandwiching the shift barrel 201 from the optical axis direction, and a fixed frame including a cover member 215. The cover member 215 is fixed to the base barrel 202 with screws. Drive means for driving the shift barrel 201 in a plane orthogonal to the optical axis is provided. The driving means includes an air-core type coil 205P, a drive magnet 203P, and a pair of drive yokes 204P and 207P facing in the optical axis direction. The coil 205P is provided in the shift barrel 201, and the drive magnet 203P and the drive yoke 204P constitute a magnetic circuit and are provided in the base barrel 202.

  The drive yoke 207P is provided on the cover member 215, and the coil 205P provided on the shift barrel 201 is disposed to face the drive magnet 203P. The cover member 215 is provided with a drop-off prevention member 215a disposed so as to pass through the air core portion of the coil provided in the shift barrel 201 from a position facing the drive magnet 203P provided in the base barrel 202. . The drop-off preventing member 215a is in contact with the drive magnet 203P to prevent the drive magnet 203P from coming off the base barrel 202 when the drive magnet 203P is about to be detached from the base barrel 202.

[Example 2]
In the second embodiment, the configuration other than the first actuator in the pitch direction and the second actuator in the yaw direction as the driving unit is the same as that in the first embodiment, and thus the description thereof is omitted. FIG. 9 shows a cross-sectional view of a drop-off prevention portion of the vibration isolation unit that is Embodiment 2 of the present invention. Reference numeral 203p denotes a drive magnet as drive means, which is held by the base barrel 202. As shown in FIG. 9, the S pole and the N pole are magnetized so as to be in opposite positions in the optical axis direction in each half of the direction orthogonal to the optical axis. Z is a neutral zone that is not magnetized.

  Reference numeral 204p denotes a back yoke disposed on the back surface of the drive magnet 203p. An upper yoke 207p fixed to the cover member 215 forms a magnetic circuit together with the drive magnet 203p and the back yoke 204p. Reference numeral 205p denotes a coil, which is arranged to face two magnetic poles arranged above and below the drive magnet 203p.

  When the coil 205p is energized, the gap constraint in the magnetic circuit and the magnetic flux generated by the coil 205p interfere magnetically to generate a so-called Lorentz force, which gives a driving force to the shift barrel 201, The shift barrel 201 is driven in the pitch direction. That is, the back actuator 204p, the upper yoke 207p, the drive magnet 203p, and the coil 205p constitute a first actuator that moves the shift barrel 201 in a pitch direction (vertical direction) orthogonal to the optical axis. The second actuator (not shown) that moves the shift barrel 201 in the yaw direction (horizontal direction) orthogonal to the optical axis has the same configuration.

  Reference numeral 215a denotes a dropout prevention unit. The width in the longitudinal direction of the drop-off prevention part 215a is larger than the longitudinal direction of the drive magnets 203p, 203y (not shown), and is integrated by the side of the holding part of the upper yoke 207p of the cover member 215. The width in the direction perpendicular to the optical axis of the drop-off prevention portion 215a is such a size as to include the width of the neutral zone Z of the drive magnets 203p and 203y (not shown). The drop-off prevention unit 215a is disposed toward the drive magnets 203p and 203y (not shown) through the air cores of the coils 205p and 205y (not shown). The dropout prevention portion 215a is not in contact with the normal drive magnets 203p and 203y (not shown).

  When an impact is applied to the shift unit from the outside and the drive magnets 203p and 203y (not shown) are about to be detached from the base barrel 202, the drive magnets 203p and 203y (not shown) abut against the drop-off preventing portion 215a. Further, since it becomes a stopper in the optical axis direction, the drive magnets 203p and 203y (not shown) are prevented from being detached from the base barrel. According to the present embodiment, the drop-off preventing portion can be formed even in the small drive means on one side of the drive magnet.

  The drop-off prevention unit 215a passes through the air cores of coils 205p and 205y (not shown), which are originally vacant spaces, and prevents the vibration isolation unit from becoming large. Further, the width in the driving direction of the drop-off prevention part is such a size as to include the width of the neutral zone Z of the drive magnets 203p, 203y (not shown). As a result, the drive magnets 203p and 203y (not shown) are prevented from falling off from the base barrel 202 while preventing the coil from becoming larger, that is, preventing the shift unit from becoming larger. Although the drop-off prevention portion may be a separate body, in this embodiment, since it is formed integrally with the cover member 215, the number of work steps is not increased and the cost is not increased. 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.

  As described above, according to the present invention, even if the magnet is about to be detached from the fixed frame due to an impact, the drop-off prevention portion serves as a stopper in the optical axis direction, thereby preventing the drop-off from the fixed frame. Since the dropout prevention part only protrudes from the fixed frame, new work is not added to prevent the dropout prevention. Furthermore, since the drop-off prevention part passes through the air core part of the coil, the vibration-proof unit can be prevented from dropping without increasing the size of the vibration isolation unit.

Reference Signs List 101 shift barrel 102 base barrel 103 drive magnet 104 drive yoke 105 coil 106 drive magnet 107 drive yoke 109 first ball 110 guide member 111 roll prevention member 112 second ball 113 third ball 114 guide spring 115 cover member 116 FPC holding sheet metal 117 Sensor holding sheet metal 118 FPC guide

Claims (9)

A shift barrel that holds the lens and moves in a plane perpendicular to the optical axis;
A fixed frame that supports the shift lens barrel so as to be movable in a plane perpendicular to the optical axis so as to oppose the optical axis direction;
Driving means for driving the shift barrel in a plane perpendicular to the optical axis;
The driving means has an air-core type coil and a drive magnet,
The fixing frame is provided with a drop-off prevention member disposed through the air core portion of the coil from a position facing the drive magnet.
The lens barrel, wherein the drop-off preventing member comes into contact with the drive magnet when the drive magnet is about to be detached from a member to which the drive magnet is attached. 2. The lens barrel according to claim 1, wherein the drop-off prevention member is provided at a distance from the drive magnet so that the drive magnet is not detached from the member. The member is a drive yoke, and the drive magnet is attached to the drive yoke by magnetic attraction;
The distance is set so that the attracted state can be recovered again by the magnetic attractive force between the drive magnet and the drive yoke even if the drive magnet is detached from the drive yoke. Lens barrel. The lens barrel according to claim 3, wherein the interval is 35 μm to 173 μm. The lens barrel according to claim 1, wherein the drop-off preventing member is in contact with the drive magnet and restricts the movement of the drive magnet in the optical axis direction. 6. The lens barrel according to claim 1, wherein two drive magnets are provided and are opposed to each other in the optical axis direction with the air-core coil interposed therebetween. The lens barrel according to claim 1, wherein the drop-off preventing member is a plate-like or bar-like protrusion.   The lens barrel according to any one of claims 1 to 7, wherein a width of the drop-off prevention member in a direction perpendicular to the optical axis is a size including a neutral zone of the drive magnet.   An optical apparatus comprising the lens barrel according to claim 1.