JP2013134325A - Lens barrel, imaging apparatus, and optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel which can be miniaturized and can stably drive a correction lens.SOLUTION: Image blur correction means of a lens barrel includes magnets 43p and 43y and coil units 45p and 45y moving a four group holding frame 43 holding a correction lens L4c relatively to a four group base plate 42, springs 47a and 47b urging the four group holding frame 43 to the four group base plate 42, and three balls 46a to 46c held between the four group holding frame 43 and the four group base plate 42. Three balls 46a to 46c are arranged so that a triangle formed by connecting three balls 46a to 46c is asymmetrical with respect to a straight line orthogonal to an optical axis B; the centroid of the four group holding frame 43 is located in the triangle, when the four group holding frame 43 is positioned to make the center of the correction lens L4c coincident with the optical axis B; and the springs 47a and 47b are arranged to be parallel with the optical axis B in a position where the springs 47a and 47b are asymmetrical with respect to the straight line.

Description

  The present invention relates to a lens barrel, and an imaging device and an optical device including the lens barrel.

  2. Description of the Related Art Conventionally, an imaging device such as a digital camera has been provided with an image blur correction device that corrects image blur due to camera shake or the like that is likely to occur in hand-held shooting. As an example of the image blur correction device, an image blur correction lens is included in an imaging lens. An optical image stabilization unit having a structure including the above is known. As the optical image stabilization unit, the first direction in the plane perpendicular to the optical axis or the second direction orthogonal to the first direction without rotating the image blur correction lens around the optical axis. There is known one that eliminates the image blur by shifting to (see Patent Document 1).

  FIG. 11 is an exploded perspective view showing a schematic structure of an optical image stabilization unit included in the imaging apparatus described in Patent Document 1. FIG. 12 is a front view showing a structure in which some constituent members (the yoke holding member 160 and the flexible wiring board 150) are removed from the optical image stabilization unit shown in FIG.

  In the optical image stabilization unit shown in FIGS. 11 and 12, the movable holding member 110 that holds the lens G <b> 5 is slidable on the substantially rectangular base 100 by the four protrusions 118 a to 118 d formed on the movable holding member 110. It is in contact. The movable holding member 110 is urged toward the base 100 by two urging springs 120 and is moved in a plane orthogonal to the optical axis AX. The movable holding member 110 is driven in a first direction (S4 direction) by a first driving mechanism including a first magnet 131 and a first coil 132, and is moved by a second driving mechanism including a second magnet 141 and a second coil 142. It is driven in two directions (S3 direction). The first drive mechanism and the second drive mechanism are arranged at positions that are line-symmetric with respect to the first straight line S1 orthogonal to the optical axis AX.

JP 2010-85448 A

  However, in the optical image stabilization unit shown in FIGS. 11 and 12, a space for providing the four protrusions 118a to 118d is required, so that the lens unit including the movable lens group such as the lens G5 becomes large, and the entire camera. Is one of the factors that increase

  In the case where the four protrusions 118a to 118d are provided as shown in FIG. 12, the spring force of the two biasing springs 120 is combined when the movable holding member 110 is stationary (hereinafter referred to as “biasing spring force synthesis”). The point) is coincident with the position of the optical axis AX. Therefore, even if the movable holding member 110 is shifted, the biasing spring force composite point remains inside the quadrangle formed by the four protrusions 118a to 118d, so that the movable holding member 110 can be stably shifted. .

  However, if, for example, one protrusion, for example, the protrusion 118b as shown in FIG. 13 is excluded from the four protrusions 118a to 118d, the biasing spring force composite point is that of the triangle T formed by the three protrusions 118a to 118c. It will be located near the outside. FIG. 13 is a front view showing a structure in which the protrusion 118b is excluded from the structure of FIG. 12 as one protrusion.

  In such a structure, when the movable holding member 110 is shifted, the balance with which the movable holding member 110 comes into contact with the base 100 is lost, and one of the movable holding members 110 is lifted to appropriately correct the image blur. Can not be. That is, in the optical image stabilization unit shown in FIGS. 11 and 12, the degree of freedom of component arrangement is not large.

  The present invention provides a lens barrel that can be miniaturized, can improve the degree of freedom of component arrangement, and includes an image blur correction device that can stably drive a correction lens. With the goal.

  The lens barrel according to the present invention is a lens barrel including an image shake correction device, and the image shake correction device includes a base member, a holding member that holds an image shake correction lens, the base member, and the The three balls disposed between the holding member, the base member and the holding member, and the base member and the holding member so that the three balls are clamped by the base member and the holding member. Two urging members for urging the holding member with respect to the member, and a symmetric arrangement with respect to a straight line perpendicular to the optical axis of the optical system excluding the image blur correction lens, the holding member Two driving means that move relative to the base member in a plane orthogonal to the optical axis, and the three balls are formed by connecting the three balls to each other. Asymmetric shape with respect to the straight line And when the holding member is positioned so that the center of the image shake correction lens coincides with the optical axis, the image shake correction lens and the driving means are provided. The center of gravity of the holding member is located inside the triangle, and the two urging members are arranged so as to be parallel to the optical axis at a position that is asymmetric with respect to the straight line.

  According to the present invention, the lens barrel can be reduced in size, and the degree of freedom of component placement can be improved and the correction lens can be driven stably.

It is sectional drawing of the digital camera which concerns on embodiment of this invention. FIG. 2 is an assembled perspective view of the lens barrel shown in FIG. 1. FIG. 2 is an exploded perspective view of a first optical axis unit of the lens barrel shown in FIG. 1. It is a disassembled perspective view of the 2nd optical axis unit of the lens-barrel shown in FIG. FIG. 2 is an assembled perspective view of a fourth group unit of the lens barrel shown in FIG. 1. FIG. 2 is an exploded perspective view of a fourth group unit of the lens barrel shown in FIG. 1. It is a front view of the 4 group unit of the lens barrel shown in FIG. FIG. 7 is an exploded perspective view of a diaphragm / shutter constituting the fourth group unit shown in FIG. 6. FIG. 7 is a front view of a diaphragm / shutter constituting the fourth group unit shown in FIG. 6. It is a front view for demonstrating how to apply the spring in the 4 group unit shown in FIG. It is a disassembled perspective view which shows schematic structure of the optical image stabilization unit with which the conventional imaging device is provided. FIG. 12 is a front view illustrating a structure in which some components are removed from the optical image stabilization unit illustrated in FIG. 11. It is a front view which shows the structure which excluded one protrusion from the structure shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, a digital camera provided with the lens barrel according to the present invention will be taken up, and in particular, the configuration of the lens barrel and image blur correction device provided in the digital camera will be described in detail.

<Configuration of lens barrel of digital camera>
FIG. 1 is a cross-sectional view of a digital camera according to an embodiment of the present invention. 1A shows a state in which the lens barrel is retracted, and FIG. 1B shows a state in which the lens barrel is extended. FIG. 2 is an assembled perspective view of the lens barrel shown in FIG. 3 is an exploded perspective view of the first optical axis unit of the lens barrel shown in FIG. FIG. 4 is an exploded perspective view of the second optical axis unit of the lens barrel shown in FIG. The configuration of the lens barrel will be described with reference to FIGS.

  The lens barrel has a six-group lens optical system including a first group lens L1, a second group lens L2, a third group lens L3b, a fourth group lens L4a, L4b, L4c, a fifth group lens L5, and a sixth group lens L6. ing. The lens barrel further includes a prism L3a that guides light incident from the optical axis A direction in the optical axis B direction that intersects the optical axis A at approximately 90 °.

  The first group lens L1 is held by the first group lens barrel 1, and the three cam pins 1a provided below the outer peripheral surface of the first group lens barrel 1 are cam grooves 8a formed on the inner peripheral surface of the cam tube 8. Engage with. The other three cam pins 1b formed in the first group barrel 1 are inserted into the cam groove 8b formed in the inner peripheral surface of the cam barrel 8 so that a slight gap is formed. . Further, rectilinear keys (not shown) are formed at three locations on the inner peripheral surface of the first group barrel 1 and engage with rectilinear grooves 7 a formed on the outer peripheral surface of the rectilinear barrel 7.

  The second group lens L2 is held by the second group holding frame 2, and the three cam pins 2a provided on the outer periphery of the second group holding frame 2 are engaged with cam grooves 8c formed on the inner peripheral surface of the cam cylinder 8. To do. The second group holding frame 2 has rectilinear keys formed at the same positions as the cam pins 2 a, and these rectilinear keys engage with rectilinear grooves (not shown) formed in the rectilinear cylinder 7.

  A groove (not shown) is formed below the inner peripheral surface of the cam cylinder 8, and this groove engages with a plurality of protrusions 7 d formed below the outer peripheral surface of the rectilinear cylinder 7. The cam cylinder 8 is rotatably supported by the rectilinear cylinder 7 and moves integrally with the rectilinear cylinder 7. Further, three cam pins 8 e provided below the outer peripheral surface of the cam cylinder 8 engage with cam grooves 9 a formed on the inner peripheral surface of the fixed cylinder 9.

  The rectilinear cylinder 7 supports the first group barrel 1 and the second group holding frame 2 in a non-rotatable manner. Four rectilinear keys 7e are formed at the lower end of the outer peripheral surface of the rectilinear cylinder 7, and these four rectilinear keys 7e engage with rectilinear grooves (not shown) formed on the inner peripheral surface of the fixed cylinder 9. To do.

  A gear part (not shown) is formed below the outer peripheral surface of the cam cylinder 8, and this gear part is connected to a cam cylinder driving device constituted by a DC motor 14 and a plurality of gear parts 15. When the cam cylinder 8 is rotated by the output of the cam cylinder driving device, the cam cylinder 8 moves in the direction of the optical axis A while rotating by the action of the cam pin 8e of the cam cylinder 8 and the cam groove 9a of the fixed cylinder 9.

  The first group barrel 1 has an engaging action between the cam pin 1a of the first group barrel 1 and the cam groove 8a of the cam barrel 8, and the straight movement key 1c of the first group barrel 1 and the straight movement groove 7a of the straight barrel 7. Due to the engaging action, it moves in the direction of the optical axis A without rotating. Further, the second group holding frame 2 has an engaging action between the cam pin 2a of the second group holding frame 2 and the cam groove 8c of the cam cylinder 8, and a straight movement key (not shown) of the second group holding frame 2 and the straight movement cylinder 7. It moves in the direction of the optical axis A without rotating due to the action of a rectilinear groove (not shown).

  The prism L3a and the third group lens L3b are held by the third group holding frame 3. The positioning part 3a and the steadying part 3b formed on the third group holding frame 3 respectively engage with two guide shafts (hereinafter referred to as “guide bars”) 12a and 12b arranged on the fixed base plate 10. Thereby, the third group holding frame 3 is supported by the fixed base plate 10 so as to be movable in the optical axis B direction. Further, a gear portion 3 c is formed in the third group holding frame 3, and the gear portion 3 c is connected to a third group driving device constituted by a stepping motor 16 and a plurality of gear parts 17. When the third group holding frame 3 is driven by the output from the third group driving device, the third group holding frame 3 is rotated by the engaging action of the positioning portion 3a and the steady rest portion 3b and the guide bars 12a and 12b. Without moving in the direction of the optical axis B.

  The fourth group lens L4a is held by an aperture / shutter 41 that is a light amount adjustment unit. The fourth group lens L4b is held by the fourth group base plate 42 (base member). The fourth group lens L4c, which is an image blur correction lens, is held by a fourth group holding frame 43, which is a holding member. The positioning portion 42a and the steadying portion 42b formed on the fourth group base plate 42 engage with the guide bars 12a and 12b arranged on the fixed base plate 10, respectively. Thereby, the 4th group ground plane 42 is supported by the fixed ground plane 10 so that a movement in the optical axis B direction is possible.

  Further, the rack 20 (see FIG. 5) is arranged on the fourth group base plate 42. The rack 20 functions as a connecting member and is screwed into a screw of the stepping motor 18 that is a drive source. When the rack 20 is driven by the output of the stepping motor 18, the fourth group base plate 42 is not rotated in the direction of the optical axis B by the engaging action of the positioning part 42a and the steadying part 42b and the guide bars 12a and 12b. Moving. The sensor holder 44 shown in FIG. 1 will be described later with reference to FIG.

  The fifth group lens L5 is held by the fifth group holding frame 5. The positioning part 5a and the steadying part 5b formed on the fifth group holding frame 5 are engaged with guide bars 12a and 12b arranged on the fixed base plate 10, respectively. Accordingly, the fifth group holding frame 5 is supported by the fixed base plate 10 so as to be movable in the optical axis B direction. Further, the fifth group holding frame 5 is urged by a fifth group spring 13 so as to contact a contact portion (not shown) of the fixed ground plate 10.

  The sixth group lens L6 is held by the sixth group holding frame 6. The positioning part 6 a and the steadying part 6 b formed on the sixth group holding frame 6 are respectively engaged with guide bars 12 a and 12 b arranged on the fixed base plate 10. Accordingly, the sixth group holding frame 6 is supported by the fixed base plate 10 so as to be movable in the optical axis B direction.

  A rack (not shown) is disposed on the sixth group holding frame 6 and is screwed into the screw of the stepping motor 19. When the rack of the sixth group holding frame 6 is driven by the output of the stepping motor 19, the sixth group holding frame 6 is rotated by the engaging action of the positioning portion 6a and the steady rest portion 6b and the guide bars 12a and 12b. Without moving in the direction of the optical axis B.

  An image sensor S and an optical filter F are held on the fixed ground plane 10. The fixed cylinder 9 and the cover 11 are fixed to the fixed base plate 10 by screws (not shown).

  In the lens barrel having the above-described structure, when the lens barrel is retracted, the 6th group holding frame 6 is first moved to the image plane side, and then the 4th group base plate 42 is moved while extruding the 5th group holding frame 5, and finally 3 The group holding frame 3 moves from the inside of the fixed cylinder 9. Then, the first group barrel 1, the second group holding frame 2, the rectilinear cylinder 7, and the cam cylinder 8 are moved into a space generated by the third group holding frame 3 being retracted from the inside of the fixed cylinder 9. At the time of shooting (during feeding), on the contrary, the third group holding frame 3 is formed in the space formed by the movement of the first group barrel 1, the second group holding frame 2, the rectilinear barrel 7, and the cam barrel 8 toward the subject. And the fourth group base plate 42, the fifth group holding frame 5, and the sixth group holding frame 6 move to predetermined positions.

<Configuration of 4 group unit>
The fourth group unit is a unit having a fourth group lens L4a, L4b, L4c and a diaphragm / shutter 41 for holding them as a central component, a fourth group base plate 42, and a fourth group holding frame 43 as central components, and an image blur correction mechanism. And a shutter / aperture mechanism. The configuration of this 4-group unit will be described with reference to FIGS.

  5 is an assembled perspective view of the fourth group unit, FIG. 6 is an exploded perspective view of the fourth group unit, and FIG. 7 is a front view of the fourth group unit. The front view of the fourth group unit in FIG. 7 is drawn in a direction in which the sixth group holding frame 6 is viewed from the third group holding frame 3 along the axial direction of the optical axis B. At this time, since the spring 47a is located on the back side of the rack 20, the spring 47a cannot be seen due to the illustration of the rack 20. Therefore, FIG. 7A shows a front view in which the rack 20 is not shown, and FIG. 7B shows a front view in which the rack 20 is shown.

  A fourth group holding frame 43 that holds a fourth group lens L4c (hereinafter referred to as “correction lens L4c”) that is an image blur correction lens holds two magnets 43p and 43y. The subscripts “p” and “y” used in the reference numerals “43p” and “43y” correspond to the P direction and the Y direction shown in FIG. 7, respectively. Orthogonal.

  The fourth group holding frame 43 is provided with hook locking portions 43a and 43b at two locations, and springs 47a and 47b as urging members for applying a tensile force are hooked on the hook locking portions 43a and 43b, respectively. (See FIG. 6). For example, coil springs are preferably used as the springs 47a and 47b.

  Two coil units 45p and 45y comprising a coil and a bobbin are fixed to the recess of the fourth group base plate 42 by adhesion so as to face the magnets 43p and 43y. Metal pins electrically connected to each coil are embedded in each bobbin, and each coil is driven by energizing each metal pin from a later-described fourth group FPC 49 (flexible printed circuit board). Is called. That is, when the energization to the coil unit 45p is turned on / off, the fourth group holding frame 43 is driven in the P direction by the electromagnetic driving force generated by the magnet 43p and the coil unit 45p. Also, the fourth group holding frame 43 is driven in the Y direction by the electromagnetic driving force generated by the magnet 43y and the coil unit 45y by turning on / off the energization to the coil unit 45y.

  The other end of the spring 47 a hung on the hook locking portion 43 a of the fourth group holding frame 43 is hooked on a hook locking portion 42 c provided on the fourth group base plate 42. The other end of the spring 47 b hung on the hook locking portion 43 b of the fourth group holding frame 43 is hooked on a hook locking portion (not shown) provided on the fourth group base plate 42. Three non-magnetic balls 46a, 46b, 46c are arranged between the fourth group base plate 42 and the fourth group holding frame 43 (see FIG. 6).

  The fourth group holding frame 43 is pressed against the fourth group base plate 42 via the balls 46a, 46b, and 46c by the urging force of the springs 47a and 47b. In other words, the balls 46 a, 46 b, 46 c are held between the fourth group base plate 42 and the fourth group holding frame 43 by the urging force of the springs 47 a, 47 b. Thus, since the fourth group holding frame 43 is supported by the fourth group base plate 42 via the balls 46a, 46b, 46c, the fourth group holding frame 43 can move freely within a plane perpendicular to the optical axis B. In the digital camera according to the present embodiment, image blur on the image sensor S is suppressed and corrected by moving the fourth group holding frame 43 relative to the fourth group base plate 42 in a plane perpendicular to the optical axis B. I do.

  An actuator 416 of the diaphragm / shutter 41 is connected to the fourth group FPC 49 by soldering. The fourth group FPC 49 includes lands 49a and 49b connected to the coil units 45p and 45y by soldering. On the back side of the fourth group FPC 49, two Hall elements (not shown) for detecting a change in the magnetic field are mounted on each of the coil units 45p and 45y.

  The magnets 43p and 43y held by the fourth group holding member 43 are magnetized in the directions shown in FIG. 7 (S pole, N pole). Changes in the magnetic fields of the magnets 43p and 43y accompanying the movement of the fourth group holding frame 43 in the P direction and the Y direction are detected by each Hall element, and the amount of movement of the fourth group holding frame 43 is calculated based on the detected amount of change. Is done. Therefore, the positional accuracy of the magnets 43p and 43y and each Hall element is important. In the present embodiment, each Hall element is positioned with high accuracy by being press-fitted into the sensor holder 44.

  The fourth group FPC 49 is fixed to the sensor holder 44 by engaging the positioning holes 49 c formed in the fourth group FPC 49 and the positioning protrusions 44 a (see FIG. 6) formed in the sensor holder 44. The sensor holder 44 is attached to the fourth group base plate 42.

[Detailed Structure of Shutter / Shutter 41]
FIG. 8 is an exploded perspective view of the diaphragm / shutter 41. FIG. 9 is a front view of the diaphragm shutter 41. The diaphragm / shutter 41 is fixed to the fourth group base plate 42 by screws 48a and 48b functioning as fixing members (see FIG. 6). The screws 48a and 48b are bosses 417a and 417b formed on the diaphragm / shutter 41, respectively. Mates with.

  The diaphragm shutter 41 has a structure in which two shutter blades 413 and 414 are disposed between a shutter base plate 411 and a shutter cover 412. The shutter base plate 411 is provided with three locking portions 411b. The locking portions 411b are locked to the locking portions 412a formed on the shutter cover 412, so that the shutter cover 412 is fixed to the shutter base plate. 411 is fixed. The shutter base plate 411 is provided with guide shafts 411a at two locations, and the guide shafts 411a are inserted into elongated holes 413a and 414a formed at two locations on the shutter blades 413 and 414, respectively.

  The shutter blades 413 and 414 are driven by an actuator 416, and a drive arm 415 is fixed to the rotation shaft of the actuator 416. Drive shafts 415a and 415b are formed at both ends of the drive arm 415, and the drive shafts 415a and 415b are inserted into elongated holes 413b and 414b formed in the shutter blades 413 and 414, respectively.

  The drive arm 415 is rotated by the output of the actuator 416. Then, the shutter blade 413 moves without rotating by the action of the long hole 413a of the shutter blade 413 and the guide shaft 411a of the shutter base plate 411 and the action of the long hole 413b of the shutter blade 413 and the drive shaft 415a of the drive arm 415. To do. Further, the shutter blade 414 rotates by the action of the long hole 414a of the shutter blade 414 and the guide shaft 411a of the shutter base plate 411 and the action of the long hole 414b of the shutter blade 414 and the drive shaft 415b of the drive arm 415. Without moving, the shutter blade 413 moves in the opposite direction. Thus, the aperture formed by the shutter blades 413 and 414 is adjusted to realize the aperture function, and the shutter is realized by driving the aperture from the open state to the closed state.

<Stability of the fourth group holding frame 43 with respect to the fourth group base plate 42>
The stability of the fourth group holding frame 43 holding the correction lens L4c with respect to the fourth group base plate 42 will be described with reference to FIG.

  The fourth group holding frame 43 is formed of a mold member (resin). Here, as described above, since the correction lens L4c and the magnets 43p and 43y are provided, the weight (weight) of the fourth group holding frame 43 is mainly governed by the weight of the correction lens L4c and the magnets 43p and 43y. ing. Therefore, when the image blur correction is started, the center of the correction lens L4c coincides with the optical axis B by the driving force of the magnets 43p and 43y and the coil units 45p and 45y in the fourth group holding frame 43 against the weight. Lifted up.

  7A and 7B show a state where the fourth group holding frame 43 is lifted and positioned so that the center of the correction lens L4c coincides with the optical axis B. FIG. At this time, the center of gravity 43g of the fourth group holding frame 43 that holds the correction lens L4c and to which the magnets 43p and 43y are attached is at the position indicated by the triangle mark “▲” in FIGS. 7 (a) and 7 (b). . The three balls 46a, 46b, 46c are included inside a triangle 46d (hereinafter simply referred to as “triangle 46d”) in which the center of gravity 43g of the fourth group holding frame 43 is formed by the three balls 46a, 46b, 46c. It is arranged to be.

  Further, the springs 47a and 47b are hooked between the fourth group holding frame 43 and the fourth group base plate 42 in parallel with the optical axis B direction so that the fourth group holding frame 43 and the fourth group base plate 42 are pressed against each other. Two balls 46 a, 46 b, 46 c are sandwiched between the fourth group holding frame 43 and the fourth group base plate 42. Here, if the triangle 46d has a structure in which the point 47c where the spring forces of the springs 47a and 47b are combined is not included in the triangle 46d, the fourth group holding frame 43 falls down at the point 47c, and the fourth group holding frame. 43 cannot be moved in a plane orthogonal to the optical axis B. Accordingly, the positions of the three balls 46a, 46b, 46c and the springs 47a, 47b are set so that the point 47c where the spring forces of the springs 47a, 47b are combined is included in the triangle 46d. Further, when the center of gravity 46g of the triangle 46d and the point 47c where the spring forces of the springs 47a and 47b are combined with each other, the fourth group holding frame 43 can be held most stably.

  As shown in FIGS. 6 and 7, the fourth group ground plane 42 has a substantially rectangular (substantially rectangular) surface substantially parallel to the optical axis A. In this embodiment, in order to optimally arrange the fourth group holding frame 43 with respect to the fourth group base plate 42, the magnets 43p and 43y and the coils 45p and 45y are parallel to the optical axis A and the optical axis of the correction lens L4c. They are arranged at positions that are symmetric with respect to the symmetry axis Z, which is a straight line passing through B. Therefore, it is desirable that the three balls 46a, 46b, and 46c be arranged so that the triangle 46d also has a symmetrical shape with respect to the symmetry axis Z. For the same reason, it is desirable that the springs 47a and 47b are also arranged at symmetrical positions with respect to the symmetry axis Z.

  However, in the present embodiment, since the shape of the surface substantially parallel to the optical axis A in the fourth group base plate 42 is substantially rectangular, the ratio of the fourth group lens L4b to the fourth group base plate 42 is large, and the ball 46c is symmetrical. It is difficult to arrange on the axis Z. That is, it is difficult to arrange the three balls 46a, 46b, 46c so that the triangle 46d is an isosceles triangle having a symmetric shape with respect to the symmetry axis Z. Therefore, the triangle 46d is asymmetric with respect to the symmetry axis Z. It must be a simple shape.

  Therefore, when determining the arrangement of the three balls 46a, 46b, and 46c, first, consider the arrangement of the three balls 46a, 46b, and 46c when the springs 47a and 47b are arranged at positions symmetrical with respect to the symmetry axis Z. FIG. 10 is a front view for explaining how to hang springs 47a and 47b in the fourth group unit.

  The springs 47a and 47b are disposed on the short side of the fourth group base plate 42 that is substantially rectangular. As shown in FIG. 10A, when the springs 47a and 47b are arranged on the ball 46c side (+ Z side), a point 47c where the spring forces of the springs 47a and 47b are combined is a line connecting the balls 46b and 46c. In order to approach the minute, a force is applied to the outside of the triangle 46d even though it is inside. Therefore, as shown in FIG. 10B, it is understood that the springs 47a and 47b are preferably arranged on the balls 46a and 46c side (−Z side).

  However, in the present embodiment, as shown in FIGS. 7A and 7B, the fourth group base plate 42 is formed with a positioning portion 42 a for inserting the guide bar 12 a and a rack holding portion 42 e for holding the rack 20. Therefore, it is difficult to arrange the springs 47a and 47b on the -Z side. On the other hand, since the guide bars 12a and 12b are arranged on the −Z side from the cam cylinder 8 so as not to interfere with the cam cylinder 8, it is difficult to move the guide bar 12a to the + Z side. Further, the rack 20 is also closer to the guide bar 12a, because a sliding load such as a twisting is reduced. Therefore, it is difficult to separate the rack 20 from the guide bar 12a. Therefore, the spring 47a must be disposed on the + Z side from the positioning portion 42a of the fourth group base plate 42 and the rack holding portion 42e.

  Therefore, in the present embodiment, as shown in FIGS. 7A and 7B, in order to arrange the spring 47a on the −Z side as much as possible, a part of the spring 47a is partly attached to the rack holding portion 42e of the fourth group base plate 42. And the rack 20 are arranged so as to overlap in a plane orthogonal to the optical axis B. Further, the spring 47b is arranged in the middle of the screw 48b and the steadying portion 42b so that the spring 47b is arranged on the −Z side with respect to the spring 47a, and a point 47c where the spring forces of the springs 47a and 47b are combined is provided. It is positioned in the vicinity of the center of gravity 46g of the triangle 46d. That is, by arranging the springs 47a and 47b at positions that are asymmetric with respect to the symmetry axis Z, the fourth group holding frame 43 can be stably held.

  As shown in FIG. 9, most of the shutter base plate 411 is occupied by a space where the shutter blades 413 and 414 move and a space where the drive arm 415 rotates. Therefore, the boss 417b for fastening the screw 48b can be disposed only in the immediate vicinity of the rotation axis of the drive arm 415. That is, by arranging the springs 47a and 47b asymmetrically with respect to the symmetry axis Z, the screw 48b is arranged at an optimal position. In other words, by arranging the springs 47a and 47b asymmetrically with respect to the symmetry axis Z, it is possible to improve the degree of freedom in arranging parts other than the springs 47a and 47b.

<Other embodiments>
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to said embodiment, A various deformation | transformation and change are possible within the range of the summary. For example, in the above-described embodiment, the configuration in which the magnets 43p and 43y are attached to the fourth group holding frame 43 has been described. However, the coil units 45p and 45y may be attached to the fourth group holding frame 43. At this time, the magnets 43 p and 43 y are attached to the fourth group base plate 42. Regarding the center of gravity, the center of gravity of the fourth group holding frame 43 to which the coil units 45p and 45y are attached and the correction lens L4c is held may be considered.

  Furthermore, in the above-described embodiment, the digital camera as an image pickup apparatus having an image shake correction mechanism is taken up. However, the present invention is not limited to this, and an optical device such as a camera-equipped mobile phone or binoculars having an image pickup function capable of image shake correction It can also be applied to devices.

L4c 4th group lens 12a, 12b Guide bar 18 Stepping motor 20 Rack 41 Shutter combined with shutter 42 4th group base plate 42a Positioning part 42b Stabilizing part 42e Rack holding part 43 4th group holding frame 43p, 43y Magnet 45p, 45y Coil unit 46a, 46b , 46c Ball 47a, 47b Spring 48a, 48b Screw

Claims (7)

A lens barrel provided with an image blur correction device,
The image blur correction device includes:
A base member;
A holding member for holding an image blur correction lens;
Three balls disposed between the base member and the holding member;
Two urging forces that are engaged with the base member and the holding member, and that urge the holding member against the base member so that the three balls are sandwiched between the base member and the holding member. Members,
Arranged so as to be symmetric with respect to a straight line orthogonal to the optical axis of the optical system excluding the image blur correction lens, the holding member is positioned relative to the base member in a plane orthogonal to the optical axis. Two drive means to be moved,
The three balls are arranged so that a triangle formed by connecting the three balls has an asymmetric shape with respect to the straight line,
When the holding member is positioned so that the center of the image blur correcting lens coincides with the optical axis, the center of gravity of the holding member in the state in which the image blur correcting lens and the driving unit are provided is A lens barrel, wherein the lens barrel is located inside a triangle and is disposed so as to be parallel to the optical axis at a position that is asymmetric with respect to the straight line. Each of the two driving means is
A magnet attached to the holding member;
The lens barrel according to claim 1, further comprising a coil attached to the base member so as to face the magnet.   3. The lens barrel according to claim 1, wherein the base member has a substantially rectangular shape, and the urging member is disposed on a short side of the base member. The base member is
A positioning part and a steadying part into which two guide shafts for guiding the base member in the axial direction of the optical axis are respectively inserted;
Holding a holding member connected to a drive source that drives the base member in the axial direction of the optical axis,
When viewed from the axial direction of the optical axis, a part of one of the two urging members is disposed at a position overlapping the holding portion and the connecting member. The lens barrel according to any one of claims 1 to 3. A light amount adjustment unit for moving a plurality of blades in a plane perpendicular to the optical axis;
Two fixing members for fixing the light amount adjustment unit to the base member,
The lens barrel according to claim 4, wherein one of the two urging members is disposed between one of the two fixing members and the steadying portion.   An optical apparatus comprising the lens barrel according to any one of claims 1 to 4.   An imaging apparatus comprising the lens barrel according to any one of claims 1 to 5.

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