JP2012053411A - Lens barrel and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel and imaging apparatus, which can surely retreat lens groups while ensuring design flexibility of the lens barrel.SOLUTION: A lens barrel includes: a barrel which has multiple cylindrical bodies overlapping telescopically to be extended and withdrawn, and collapses by withdrawing the extended multiple cylindrical bodies; an optical system with multiple lens groups contained in the barrel; a lens frame for holding the lens group which is located at the rearmost end along an optical axis in a state in which the multiple cylindrical bodies are extended and retreated to a position located out of the optical axis accompanying the collapse of the barrel; and a cam ring which rotates within a plane perpendicular to the optical axis. The cam ring rotates by being brought into contact with any of the multiple cylindrical bodies that retreat along the optical axis accompanying the collapse of the barrel, and has an engaging section that allows the lens frame to retreat by engaging with a part of the lens frame.

Description

  The present invention relates to a lens barrel and an imaging device.

  Currently, digital cameras are widely used. In digital cameras, there is a demand for ever-increasing image quality along with downsizing and thinning. As one of digital cameras that meet this need, an imaging apparatus having a retractable lens barrel has been proposed. Such a lens barrel has a plurality of cylindrical bodies arranged coaxially, and includes a barrel that is extended and retracted. The lens barrel houses an optical system. The lens barrel can be shortened by retracting a plurality of cylinders at times other than when photographing, and thus the imaging apparatus can be miniaturized.

  As the lens barrel, a variable power lens group that performs variable power adjustment, a focus lens group that performs focus adjustment, and other lens groups are housed side by side in the direction of the optical axis in a lens barrel, and further, light quantity control such as a shutter or a diaphragm A member is provided. The imaging apparatus includes a solid-state imaging device, and obtains an image by forming an image of light incident on the lens barrel on an imaging surface of the solid-state imaging device.

  Currently, as a lens barrel, in order to avoid the lens groups from interfering when retracted, part of the plurality of lens groups is retracted to a position off the optical axis, and the lens barrel is further shortened. Something that makes it possible has been proposed. For example, Patent Document 1 describes a digital camera including a lens barrel that retracts a lens group that performs zoom adjustment to a position that deviates from the optical axis.

  Such a lens barrel includes a barrel that accommodates a plurality of coaxially arranged cylindrical bodies, and a cam is formed in a fixed cylindrical body that is disposed rearward with respect to the optical axis direction. The retracted lens group is held by the lens frame, and the lens frame moves the lens group by a cam. At this time, the retract timing of the retracted lens group is defined by the shape of the cam groove formed on the inner surface of the cylinder and the inclination angle with respect to the axial direction. However, in such a configuration, when the number of lens groups accommodated in the lens barrel increases, the positional relationship between the retracted lens group and the other lens groups becomes complicated, and the cam groove prevents the lens groups from interfering with each other. It becomes difficult to design. For this reason, the design freedom of the lens barrel cannot be improved.

JP 2004-317943 A

  Provided are a lens barrel and an imaging apparatus capable of securely retracting a lens group while ensuring a degree of freedom in designing the lens barrel.

A lens barrel that includes a plurality of cylinders that can be extended and retracted in a nested manner, and retracts by retracting the plurality of cylinders that have been extended.
An optical system including a plurality of lens groups housed in the lens barrel;
The lens group disposed at the rearmost position along the optical axis in a state in which the plurality of cylindrical bodies are extended, and holds the lens group retracted to a position deviated from the optical axis when the lens barrel is retracted. A lens frame,
A cam ring that rotates in a plane perpendicular to the optical axis;
With
The cam ring rotates in contact with any one of the plurality of cylinders retracting along the optical axis as the lens barrel retracts, and engages a part of the lens frame. And a lens barrel having an engaging portion for retracting the lens frame.

  According to the configuration of the lens device described above, the driving force of the cylindrical body that moves backward along the optical axis when retracted is converted into the driving force in the circumferential direction by the cam ring, and the lens group is moved by the driving force in the circumferential direction of the cam ring. By rotating, the lens group is retracted. For this reason, it is not necessary to form a cam groove on the inner peripheral surface of the cylinder, and the lens group closest to the imaging surface can be retracted without depending on the complicated design of the shape and inclination angle of the cam groove. is there. In such a configuration, even when the number of lens groups accommodated in the lens barrel is increased, the degree of freedom in designing the lens barrel is improved without being influenced by other lens groups. Can be made.

  ADVANTAGE OF THE INVENTION According to this invention, the lens barrel and imaging device which can perform retraction | saving of a lens group reliably, ensuring the design freedom of a lens barrel can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external perspective view illustrating an example of an imaging apparatus for describing an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating the internal structure of the imaging apparatus in FIG. 1 in a state where a lens barrel is extended to a telephoto end. FIG. 2 is a cross-sectional view illustrating the internal structure of the imaging apparatus in FIG. 1 in a state where a lens barrel is extended to a wide end. FIG. 2 is a cross-sectional view showing the internal structure of the imaging apparatus of FIG. 1 in a state where the lens barrel is retracted to the retracted end. FIG. 2 is an exploded perspective view showing the lens barrel of FIG. 1. The perspective view which shows a 5 group unit. Explanatory drawing of the drive mechanism of a 3rd lens group. Explanatory drawing of the drive mechanism of a 5th lens group. Explanatory drawing of the drive mechanism of a 5th lens group. The figure which shows the state of the retracted 3rd lens group and 5th lens group at the time of retracting of a lens barrel. Explanatory drawing of a structure of an imaging unit.

  FIG. 1 shows an example of an imaging apparatus. FIG. 1 shows the lens barrel retracted to the retracted end when not in use.

  The imaging apparatus 1 includes a lens barrel 2 that houses an optical system, and an imaging unit 600 that includes a solid-state imaging device such as a CCD or CMOS.

  The lens barrel 2 includes a main body 6 having a first cylinder 3, a second cylinder 4, a third cylinder 5, and a housing cylinder 30 that is fitted on the outermost third cylinder 5. Contains. The third cylinder 5 is extended relative to the main body 6, the second cylinder 4 is extended relative to the third cylinder 5, and the first cylinder 3 is extended relative to the second cylinder 4. Is included. As the first cylinder 3, the second cylinder 4, and the third cylinder 5 are extended and retracted, the lens barrel 2 is extended and retracted.

  The imaging unit 600 is attached to the rear side (image side) of the lens barrel 2.

  2 and 3 show the internal structure of the imaging apparatus 1. 2 shows the lens barrel 2 extended to the telephoto end, and FIG. 3 shows the lens barrel 2 extended to the wide end.

  The optical system housed in the lens barrel 2 includes a first lens group 101, a second lens group 201, a shutter 701, a third lens group 301, a fourth lens group 401, and a fifth lens group 501. The optical elements are arranged in this order from the front side (subject side).

  The first group unit 100 including the first lens group 101 is accommodated in the first cylinder 3. The second group unit 200 including the second lens group 201 is accommodated in the second cylinder 4. The shutter unit 700 including the shutter 701, the third group unit 300 including the third lens group 301, and the fourth group unit 400 including the fourth lens group 401 are all accommodated in the third cylinder 5. The fifth group unit 500 including the fifth lens group 501 is attached to the rear part of the main body 6, and the fifth lens group 501 is accommodated in the accommodating cylinder 30 of the main body 6.

  The first lens group 101, the second lens group 201, and the third lens group 301 constitute a zoom optical system for adjusting the zoom magnification, that is, the focal length. The first lens group 101 and the second lens group 201 are variable power lens groups, and the third lens group 301 is a correction system lens group. As the lens barrel 2 is extended and retracted, the first lens group 101 and the second lens group 201 move back and forth along the optical axis, thereby changing the focal length. In synchronism with this, the third lens group 301 also advances and retreats along the optical axis, thereby suppressing the change in the focal position due to zooming.

  The shutter 701 controls exposure by opening and closing. In some cases, the opening can be varied to double as an aperture. The shutter 701 is disposed adjacent to the subject side of the third lens group 301 so that a substantially constant distance is provided between the shutter 701 and the third lens group 301 as the lens barrel 2 is extended and retracted. Advancing and retreating along the optical axis.

  The fourth lens group 401 constitutes a focus optical system for adjusting the focus position (focus adjustment). The fourth lens group 401 advances and retreats along the optical axis as the lens barrel 2 is extended and retracted. Furthermore, the fourth lens group 401 is driven by a focusing motor 403 provided in the fourth group unit 400 to move forward and backward along the optical axis, thereby changing the focal position.

  The fifth lens group 501 constitutes an optical system for finally forming an image. The position of the fifth lens group 501 remains unchanged regardless of the extension of the lens barrel 2 while the lens barrel 2 is extended from the tele end to the wide end.

  The solid-state imaging device 601 included in the imaging unit 600 is disposed at the imaging point of the optical system.

  FIG. 4 shows the internal structure of the imaging apparatus 1. In FIG. 4, the lens barrel 2 is shown retracted to the retracted end.

  When the lens barrel 2 is retracted to the retracted end, the third lens group 301 and the fifth lens group 501 are other optical elements (first lens group 101, second lens group 201, shutter 701, fourth lens). The group 401) is retracted to a position off the optical axis.

  A shutter 701 is disposed in a space generated by retracting the third lens group 301, and the third lens group 301 and the shutter 701 are arranged in a direction perpendicular to the optical axis. A fourth lens group 401 is disposed in a space generated by retracting the fifth lens group 501, and the fifth lens group 501 and the fourth lens group 401 are also arranged in a direction orthogonal to the optical axis.

  Hereinafter, the retracting mechanism of the lens barrel 2, that is, the feeding and retracting mechanisms of the first cylindrical body 3, the second cylindrical body 4, and the third cylindrical body 5, will be described. The advance / retreat mechanism of the optical elements (the first lens group 101, the second lens group 201, the third lens group 301, the fourth lens group 401, and the shutter 701) that moves forward and backward along the optical axis will be described.

  FIG. 5 shows the lens barrel 2 in an exploded manner.

  First, the feeding and feeding mechanism for the main body 6 of the third cylinder 5 will be described.

  The third cylinder 5 includes an outer cylinder 10 and an inner cylinder 11 that is rotatably fitted in the outer cylinder 10.

  Three cam followers 12 are formed at equal intervals in the circumferential direction on the outer peripheral surface of the rear end portion of the outer cylinder 10, and a plurality of gear teeth 13 are formed between two adjacent cam followers 12. ing.

  An annular flange 14 that extends outward is formed at the rear end of the inner cylinder 11. Three guide projections 15 are formed on the outer peripheral edge of the flange 14 at equal intervals in the circumferential direction.

  The main body 6 includes a housing cylinder 30 that is externally fitted to the third cylindrical body 5, and a flange 31 that extends outward from the outer peripheral edge of the rear end portion of the housing cylinder 30.

  Three cam grooves 32 are formed on the inner peripheral surface of the housing cylinder 30 at equal intervals in the circumferential direction. These cam grooves 32 are formed in a spiral shape turning around the optical axis, and the cam followers 12 of the outer cylinder 10 of the third cylinder 5 are engaged with each other.

  Further, three guide grooves 33 are formed on the inner peripheral surface of the housing cylinder 30 at equal intervals in the circumferential direction. These guide grooves 33 are formed in a straight line along the optical axis, and the guide protrusions 15 of the inner cylinder 11 of the third cylinder 5 are engaged with each other.

  In addition, the housing cylinder 30 is formed with a window that communicates the inside and the outside, and a gear (not shown) is disposed there. This gear meshes with gear teeth 13 formed on the outer cylinder 10 of the third cylinder 5. A retractable motor 34 that rotationally drives the gear is attached to the flange 31.

  When the motor 34 is operated, the outer cylinder 10 of the third cylinder 5 is rotationally driven through the gear. The outer cylinder 10 engages the cam follower 12 with the cam groove 32 of the housing cylinder 30 of the main body 6, and the cam follower 12 follows the spiral cam groove 32 as the outer cylinder 10 rotates. Thereby, the outer cylinder 10 advances and retreats along the optical axis while rotating. As a result, the third cylinder 5 is fed out and fed into the main body 6.

  The inner cylinder 11 of the third cylinder 5 is rotatable with respect to the outer cylinder 10, and the guide protrusion 15 is engaged with a linear guide groove 33 formed in the housing cylinder 30 of the stationary main body 6. Thus, the rotation with respect to the main body 6 is restricted. Therefore, the inner cylinder 11 advances and retreats along the optical axis without rotating.

  Next, the advancing / retreating mechanism of the third lens group 301 and the fourth lens group 401 accommodated in the third cylinder 5 and the shutter 701 will be described.

  The shutter unit 700 including the shutter 701, the third group unit 300 including the third lens group 301, and the fourth group unit 400 including the fourth lens group 401 are accommodated in the third cylinder 5 in this order from the front side. . The third group unit 300 is assembled to the fourth group unit 400, and advances and retreats along the optical axis integrally with the fourth group unit 400.

  The shutter unit 700 includes a holder 702 that holds the shutter 701. The holder 702 includes a holding cylinder 710 and an annular flange 711 that extends outward from the rear end portion of the holding cylinder 710. The front end of the holding cylinder 710 is provided with a lid 712, and the shutter 701 is provided in an opening formed at the center of the lid 712. Three flanges 711 are formed with three claws 713 extending forward along the optical axis at equal intervals in the circumferential direction, and cam followers 714 are provided at the tips of the claws 713.

  The fourth group unit 400 including the fourth lens group 401 includes a holder 402 that holds the fourth lens group 401. The holder 402 has a holding cylinder 410 and an annular flange that extends outward from the rear end of the holding cylinder 410. 411. The front end of the holding cylinder 410 is provided with a lid 412, and the fourth lens group 401 is disposed in an opening formed in the center of the lid 412. Three claws 413 are formed on the outer peripheral edge of the flange 411 so as to extend forward along the optical axis at equal intervals in the circumferential direction. A cam follower 414 is provided at the tip of each claw 413.

  Three first cam grooves 16 and three second cam grooves 17 are formed at equal intervals in the circumferential direction on the inner peripheral surface of the outer cylinder 10 of the third cylinder 5. These cam grooves 16 and 17 are formed in a spiral shape turning around the optical axis.

  Three first guide grooves 18 and three second guide grooves 19 are formed in the inner cylinder 11 of the third cylinder 5 at equal intervals in the circumferential direction. These guide grooves 18 and 19 are formed in a straight line along the optical axis, and are formed so as to penetrate the inner cylinder 11 from the inside to the outside. The first guide groove 18 overlaps in a partial section with a partial section of the first cam groove 16 of the outer cylinder 10, and the overlapping section has a relative rotation between the outer cylinder 10 and the inner cylinder 11. As a result, it moves back and forth along the optical axis. The second guide groove 19 overlaps with a part of the second cam groove 17 of the outer cylinder 10 in a part of the second guide groove 19, and relative rotation occurs between the outer cylinder 10 and the inner cylinder 11 in the overlapping part. It moves back and forth along the optical axis.

  The shutter unit 700 engages the cam follower 714 with the first cam groove 16 of the outer cylinder 10 through the first guide groove 18 of the inner cylinder 11. When the outer cylinder 10 rotates as the third cylinder 5 is extended and retracted, the overlapping section between the first guide groove 18 and the first cam groove 16 moves back and forth along the optical axis, and the cam follower 714 is moved there. The engaged shutter unit 700 advances and retreats along the optical axis in the third cylinder 5 in conjunction with the back and forth movement of the overlapping section.

  Similarly, the fourth group unit 400 engages the cam follower 414 with the second cam groove 17 of the outer cylinder 10 through the second guide groove 19 of the inner cylinder 11. When the outer cylinder 10 rotates as the third cylinder 5 is extended and retracted, the overlapping section between the second guide groove 19 and the second cam groove 17 moves back and forth along the optical axis, and the cam follower 414 is moved there. The engaged fourth group unit 400 moves back and forth along the optical axis in the third cylinder 5 in conjunction with the longitudinal movement of the overlapping section.

  Of the first cam groove 16 and the first guide groove 18 that drive the shutter unit 700 forward and backward, a linear first guide groove 18 is formed in the inner cylinder 11 that is allowed only to advance and retract. The shutter unit 700 having the cam follower 714 engaged with the groove 18 is restrained by the inner cylinder 11 and advances and retreats along the optical axis without rotating. Similarly, the fourth group unit 400 advances and retreats along the optical axis without rotating.

  Subsequently, the feeding and feeding mechanism of the second cylinder 4 with respect to the third cylinder 5 will be described.

  The second cylinder is composed of an outer cylinder 40, a cam cylinder 41 accommodated in the outer cylinder 40, and an inner cylinder 42 that is rotatably fitted in the cam cylinder 41.

  Three engagement recesses 43 are formed at the rear end portion of the outer cylinder 40 at equal intervals in the circumferential direction.

  The outer diameter of the cam cylinder 41 is smaller than the inner diameter of the outer cylinder 40, and a gap is placed between the inner peripheral surface of the outer cylinder 40 and the outer peripheral surface of the cam cylinder 41. Three engagement protrusions 44 are formed at equal intervals in the circumferential direction at the rear end portion of the cam cylinder 41, and a cam follower 45 is formed at the tip of each engagement protrusion 44. Each engagement protrusion 44 engages with the engagement recess 43 of the outer cylinder 40, whereby the cam cylinder 41 and the outer cylinder 40 are joined together. The cam follower 45 formed at the tip of each engagement protrusion 44 protrudes from the outer peripheral surface of the outer cylinder 40.

  Three guide grooves 20 are formed on the inner peripheral surface of the outer cylinder 10 of the third cylinder 5 at equal intervals in the circumferential direction. These guide grooves 20 are formed in a straight line along the optical axis.

  Further, three cam grooves 21 are formed in the inner cylinder 11 of the third cylinder 5 at equal intervals in the circumferential direction. These cam grooves 21 are formed in a spiral shape turning around the optical axis, and are formed so as to penetrate the inner cylinder 11 from the inside to the outside. The cam groove 21 overlaps with a partial section of the guide groove 20 of the outer cylinder 10 in the partial section, and the overlapping section is aligned with the optical axis due to relative rotation between the outer cylinder 10 and the inner cylinder 11. Move back and forth along.

  The cam cylinder 41 of the second cylinder 4 engages the cam follower 45 with the guide groove 20 of the outer cylinder 10 of the third cylinder 5 through the cam groove 21 of the inner cylinder 11 of the third cylinder 5. When the outer cylinder 10 rotates as the third cylinder 5 is extended and retracted, the overlapping section between the guide groove 20 and the cam groove 21 moves back and forth along the optical axis, and the cam follower 45 is engaged therewith. The cam cylinder 41 advances and retreats along the optical axis in conjunction with the back and forth movement of the overlapping section. As a result, the second cylinder 4 is extended and retracted with respect to the third cylinder 5.

  Of the spiral cam groove 21 and the linear guide groove 20 for driving the cam cylinder 41 forward and backward, the linear guide groove 20 is formed in the outer cylinder 10 of the rotating third cylinder body 5. The cam cylinder 41 having the cam follower 45 engaged with the guide groove 20 is restrained by the outer cylinder 10 of the third cylinder 5 and advances and retreats along the optical axis while rotating together with the outer cylinder 10 of the third cylinder 5.

  On the other hand, the inner cylinder 42 of the second cylinder 4 is rotatable with respect to the cam cylinder 41, and the inner cylinder 42 is always a holder of the shutter unit 700 regardless of whether the second cylinder 4 is extended or retracted. The front end of the holding cylinder 710 of 702 is fitted. As described above, the shutter unit 700 only advances and retreats along the optical axis without rotating, and thus the inner cylinder 42 also advances and retreats along the optical axis without rotating.

  Next, the advance / retreat mechanism of the second lens group 201 accommodated in the second cylinder 4 will be described.

  The second group unit 200 including the second lens group 201 includes a holder 202 that holds the second lens group 201, and the holder 202 has a circular holding plate 210. The second lens group 201 is disposed in an opening formed in the center of the holding plate 210. On the outer peripheral edge of the holding plate 210, three claws 211 extending rearward along the optical axis are formed at equal intervals in the circumferential direction, and a cam follower 212 is provided on each claw 211.

  Three cam grooves 46A are formed on the inner peripheral surface of the cam cylinder 41 of the second cylinder 4 at equal intervals in the circumferential direction. These cam grooves 46A are formed in a spiral shape that pivots about the optical axis.

  Three guide grooves 47 are formed in the inner cylinder 42 of the second cylinder 4 at equal intervals in the circumferential direction. These guide grooves 47 are formed linearly along the optical axis, and are formed so as to penetrate the inner cylinder 42 from the inside to the outside. The guide groove 47 overlaps with a part of the cam groove 46 </ b> A of the cam cylinder 41 in a part of the guide groove 47, and the overlap part is lighted by relative rotation between the cam cylinder 41 and the inner cylinder 42. Move back and forth along the axis.

  The second group unit 200 engages the cam follower 212 with the cam groove 46 </ b> A of the cam cylinder 41 of the second cylinder 4 through the guide groove 47 of the inner cylinder 42 of the second cylinder 4. When the cam cylinder 41 rotates as the second cylinder 4 is extended and retracted, the overlapping section between the guide groove 47 and the cam groove 46A moves back and forth along the optical axis, and the cam follower 212 is engaged therewith. The second group unit 200 moves back and forth along the optical axis in the second cylinder 4 in conjunction with the back and forth movement of the overlapping section.

  Of the cam grooves 46A and guide grooves 47 that drive the second group unit 200 to advance and retract, a linear guide groove 47 is formed in the inner cylinder 42 that is allowed only to advance and retract, and the cam follower 212 is engaged with the guide groove 47. The combined second group unit 200 is restrained by the inner cylinder 42 and advances and retreats along the optical axis without rotating.

  The feeding and feeding mechanism of the first cylinder 3 with respect to the second cylinder 4 will be described.

  The first cylinder 3 includes a first group unit 100 including a first lens group, an outer cylinder 120, a barrier unit 130, and a decorative ring 140. The barrier unit 130 and the decorative ring 140 are attached to the front end along the optical axis of the outer cylinder 120, and move forward and backward together with the outer cylinder 120.

  The first group unit 100 including the first lens group 101 includes a cylindrical holder 102 that holds the first lens group 101, and the holder 102 has a lid 110. The first lens group 101 is disposed in an opening formed in the center of the lid 110. Three pawls 111 extending rearwardly along the optical axis at equal intervals in the circumferential direction are formed at the rear end along the optical axis of the holder 102. A cam follower 112 protruding to the side is provided.

  Three cam grooves 46 </ b> B are formed on the outer peripheral surface of the cam cylinder 41 of the second cylinder 4 at equal intervals in the circumferential direction. These cam grooves 46B are formed in a spiral shape that pivots about the optical axis. The cam follower 112 of the first group unit 100 is engaged with the cam groove 46 </ b> B on the outer peripheral surface of the cam cylinder 41. In addition, three guide projections 49 are formed on the front end portion along the optical axis of the cam cylinder 41 on the radially outer side of the cam cylinder 41 at equal intervals in the circumferential direction.

  A guide groove 114 extending linearly along the optical axis is formed on the inner peripheral surface of the holder 102 of the first group unit 100. The guide protrusion 49 of the cam cylinder 41 engages with the guide groove 114. When the cam cylinder 41 rotates as the second cylinder 4 is extended and retracted, the first group unit 100 does not rotate relative to the cam cylinder 41 due to the restriction of the guide groove 114 and interlocks with the longitudinal movement of the cam cylinder 41. Then move forward and backward along the optical axis.

Next, the configuration of the fifth group unit will be described.
FIG. 6 is a perspective view showing the fifth group unit. The fifth group unit 500 includes a fifth lens group 501, a lens holding frame 502 that holds the fifth lens group 501, a rotating arm unit 504 that extends from the lens holding frame 502 perpendicular to the optical axis, And a support plate 540 supported by a rotating shaft 508. The fifth group unit 500 includes a side plate 530 to which the support plate 540 is attached.

  The side plate 530 constitutes a back plate that is attached to the rear of the housing cylinder 30. The side plate 530 is provided with an opening 534 at a position intersecting the optical axis. In the opening 534, an image pickup device provided in the image pickup unit 600 described later is arranged, and an image pickup surface of the image pickup device is exposed to the fifth lens group side.

  Further, the side plate 530 is formed with claws 532 extending vertically from the surface of the side plate 530 along the optical axis. A cam portion 532A formed in a tapered shape is provided at the tip of the claw 532.

  The support body 540 is provided with an opening at a position that intersects the optical axis. The support plate 540 is disposed in parallel to the side plate 530 with a gap in the optical axis direction. The support plate 540 is fixed to the side plate 530 with screws 542.

  The lens holding frame 502 is a frame-like member that holds the outer peripheral edge of the fifth lens group 501 while exposing the optical surface of the fifth lens group 501.

  A part of the rotation arm unit 504 is supported by a rotation shaft 508 parallel to the optical axis of the fifth lens group 501. Further, an engagement rib 510 is formed in the vicinity of a portion of the rotating arm portion 504 that is pivotally supported by the rotation shaft 508.

  The rotating shaft 508 is fixed to the support plate 540. A torsion coil spring 506 is attached to the rotation shaft 508. The torsion coil spring 506 biases the lens holding frame 502 in the rotation direction around the rotation shaft 508. Further, the torsion coil spring 506 biases the rotating arm portion 504 in a direction away from the support plate 540 along the rotation shaft 508.

  A cam ring 520 is disposed so as to surround the support plate 540 attached to the side plate 530.

  The cam ring 520 includes an annular portion 522, three claws 526 arranged at equal intervals in the circumferential direction of the annular portion 522, and an engaging portion 524 that projects to the inner diameter side of the annular portion 522. . The number of the claws 526 is not particularly limited. The cam ring 520 is attached to the rear end surface along the optical axis of the inner cylinder 11 of the third cylinder 5. The cam ring 520 is supported on a front surface along the optical axis of the side plate 530 so as to be rotatable in a plane perpendicular to the optical axis.

  The claw 526 projects vertically from the front surface along the optical axis of the annular portion 522. At the tip of the claw 526, a cam portion 526A formed in a tapered shape is provided.

Next, a mechanism for driving the third lens group and the fifth lens group to the retracted position will be described.
FIG. 7 is a diagram for explaining a driving mechanism of the third lens group. In FIG. 7, only the third group unit, the fourth group unit, and the fifth group unit are shown for simplification of explanation, and other members are omitted without being shown.

  The third group unit 300 includes a lens holding frame 302 that holds the third lens group 301, and a rotating arm unit 304 that extends perpendicularly to the optical axis from the lens holding frame 302. The rotation arm unit 304 is pivotally supported by the holder 402 so as to be rotatable about a rotation shaft 308. An engaging portion 310 is provided in the vicinity of a portion of the rotating arm portion 304 that is pivotally supported by the rotation shaft 308. A hole 416 is formed in the flange 411 of the fourth group unit 400. The claw 532 of the fifth group unit 500 is inserted into the hole 416.

As the lens barrel 2 is retracted, the third group unit 300 moves back along the optical axis as indicated by the arrow in the figure. Then, the claw 532 of the fifth group unit 500 is inserted longer through the hole 416. Then, the rotating arm portion 304 has the engaging portion 310 abuts on the cam portion 532A of the claw 532 and moves along the taper surface of the cam portion 532A, as shown by the arrow about the rotation shaft 308. Rotate. Thus, the third lens group 301 is moved away from the position on the optical axis of other optical systems such as the fourth lens group 401.

  8 and 9 are diagrams for explaining the drive mechanism of the fifth lens group. In FIG. 8, only the inner cylinder of the third cylinder and the fifth group unit are shown for simplification of explanation, and the other members are not shown in the figure.

  A slit 14 </ b> A is formed in the flange 14 of the inner cylinder 11. Further, the inner cylinder 11 has a groove 14B formed on the outer peripheral surface of the inner cylinder 11 along the optical axis from the opening portion of the slit 14A. The claw 526 of the fifth group unit 500 inserted through the slit 14A is received in the groove 14B.

  As shown in FIG. 9, as the lens barrel is retracted, the inner cylinder 11 of the third cylinder portion 5 is retracted along the optical axis as indicated by an arrow in the figure. Then, the claw 526 of the cam ring 520 is further inserted into the groove 14B. When the inner cylinder 11 is retracted as described above, only movement in the straight direction is allowed. For this reason, the cam ring 520 rotates in a direction perpendicular to the optical axis when the cam portion 526A of the claw 526 is guided along the groove 14B.

  At this time, as shown in FIG. 8, the engaging portion 524 of the rotating cam ring 520 engages with the engaging rib 510 of the lens holding frame 502 of the fifth lens group 501. Then, the lens holding frame 502 of the fifth lens group 501 rotates about the rotation shaft 508. Thus, the fifth lens group 501 is retracted away from the position on the optical axis of the other optical system.

  Further, the claw 526 of the cam ring 520 always includes the third cylindrical portion 5 including when the lens barrel 2 is used (including when the optical system is positioned at the tele end or the wide end) and when the lens barrel is retracted. Engages with the groove 14 </ b> B of the inner cylinder 11.

  The retraction of the third lens group and the fifth lens group described above is performed in synchronization with the retracting of the lens barrel.

  According to the configuration of this lens device, the retraction of the fifth lens group 501 converts the driving force of the cylinder 5 that moves backward along the optical axis in the retracted direction to the driving force in the circumferential direction by the cam ring 520 when retracted. This is realized by rotating the fifth lens group 501 by the circumferential driving force of 520. For this reason, it is not necessary to form a cam groove for retracting the lens group on the inner peripheral surface of the cylinder 5 or the housing cylinder 30, and imaging can be performed without complicated design of the shape and inclination angle of the cam groove. The lens group closest to the surface can be retracted. In the case of such a configuration, even if the number of lens groups accommodated in the lens barrel 2 increases and the positional relationship between the retracted lens group and the other lens group becomes complicated, the other lens group The degree of freedom in designing the lens barrel 2 can be improved without being affected by the above.

  The cam ring 520 is not limited to the shape of the inner cylinder 11 or the groove 14B described above, as long as the cam portion 526A of the claw 526 is in contact with any one of the cylinders that are retracted as the lens barrel retracts. .

  FIG. 10 is a diagram illustrating a state of the retracted third lens group and the fifth lens group when the lens barrel is retracted. In FIG. 10, the lens barrel 2 is viewed from the back side, and the fifth lens group unit 500 is not shown for the sake of explanation. As shown in FIG. 10, three notches 48 </ b> A, 48 </ b> B, and 48 </ b> C are formed on the inner peripheral surface of the cam cylinder 41 at equal intervals in the circumferential direction. Each of 48A, 48B, and 48C is formed by expanding a part of the inner peripheral surface of the cam cylinder 41 to the outer diameter side.

  The notch 48A accommodates a part of the lens holding frame 502 of the retracted fifth lens group 501 and the notch 48B accommodates a part of the lens retaining frame 302 of the retracted third lens group 301. The notch 48 </ b> C accommodates a part of the focusing motor 403 provided in the fourth group unit 400. In this way, when retracted, the third lens group 301, the fifth lens group 501, and the focusing motor 403 that are retracted can be accommodated in the space on the inner diameter side of the lens barrel 2, and at the retracted position, the third lens group 301, the fifth lens group 501, and the focusing motor 403 can be accommodated. The lens group 301 and the fifth lens group 501 do not interfere with each other. Further, the member accommodated in the notch 48C is not limited to the focus motor 403 but may be another member.

  Here, a state when photographing using the imaging device 1 is assumed. If the vertical direction in FIG. 10 is the vertical direction of the imaging apparatus 1 at the time of shooting, the notch 48C is positioned substantially below the central axis C of the lens barrel 2. The position of the notch 48A is shifted from the position of the notch 48C by approximately 120 degrees in the circumferential direction with respect to the central axis C. Further, the position of the notch 48B is shifted by approximately 120 degrees to the opposite side in the circumferential direction with respect to the center axis C with respect to the position of the notch 48C.

Next, the imaging unit will be described.
FIG. 11 is a diagram illustrating the configuration of the imaging unit.
The imaging unit 600 is attached to the back side of the housing cylinder 30 of the lens barrel 2. The imaging unit 600 includes an imaging element 601 disposed at an imaging point of the optical system of the lens barrel 2, and a substrate 602 to which the imaging element 601 is attached. The image sensor 601 is a solid-state image sensor such as a CCD or CMOS. The substrate 602 includes a drive circuit for driving the image sensor 601, a signal circuit for outputting an image signal from the image sensor 601, and other circuits.

  In addition, the image pickup unit 600 is provided with a shake correction mechanism. The shake correction mechanism corrects image shake due to camera shake. The substrate 602 is provided with moving means for sliding the image sensor 601 in the X direction on the XY plane perpendicular to the optical axis, and moving means for sliding in the Y direction. Each moving means has a coil 604. The coil 604 is a flat ring-shaped coil and is disposed in the vicinity of the image sensor 601. The moving means includes a permanent magnet (not shown) disposed in the vicinity of the coil 604. When the coil 604 is energized, an electromagnetic force is generated by the magnetic field generated in the coil 604 and the magnetic field of the permanent magnet. The moving means displaces the position of the image sensor 601 by this electromagnetic force. In addition, a plate 606 made of a magnetic material is attached to the substrate 602 so as to face the permanent magnet and sandwich the coil 604. The plate 606 functions as a yoke.

  The side plate 530 of the fifth group unit 500 may be made of a magnetic material so as to function as a counter yoke. In this way, by attaching the side plate 530 to the substrate 602 to serve as the yoke of the shake correction mechanism, the plate 606 attached to the substrate 602 of the imaging unit 600 can be omitted, and the number of components can be reduced. it can. When the side plate 530 is an opposing yoke, for example, it is preferable that the material of the side plate 530 is SUS and the thickness of the side plate 530 is 0.4 mm or more.

This specification describes the following matters.
(1) A lens barrel that includes a plurality of cylinders that can be extended and retracted in a nested manner and that retracts and retracts the plurality of cylinders that are extended.
An optical system including a plurality of lens groups housed in the lens barrel;
The lens group disposed at the rearmost position along the optical axis in a state in which the plurality of cylindrical bodies are extended, and holds the lens group retracted to a position deviated from the optical axis when the lens barrel is retracted. A lens frame,
A cam ring that rotates in a plane perpendicular to the optical axis;
With
The cam ring rotates in contact with any one of the plurality of cylinders retracting along the optical axis as the lens barrel retracts, and engages a part of the lens frame. And a lens barrel having an engaging portion for retracting the lens frame.
(2) The lens barrel according to (1),
The plurality of lens groups include a variable power system lens group, a correction system lens group, and a focus optical system lens group, and the lens group held by the lens frame is the variable power system lens group among the plurality of lens groups. And a lens barrel other than the correction system lens group and the focus optical system lens group.
(3) The lens barrel according to (1) or (2),
The cam ring includes a claw protruding along the optical axis so that the cam ring is always engaged with one of the plurality of cylinders when the plurality of cylinders are extended.
(4) The lens barrel according to any one of (1) to (3);
An imaging device disposed at an imaging point of the optical system of the lens barrel.

DESCRIPTION OF SYMBOLS 1 Imaging device 2 Lens barrel 3 1st cylinder 4 2nd cylinder 5 3rd cylinder 6 Main body 10 Outer cylinder 11 (of 3rd cylinder) Inner cylinder 30 (of 3rd cylinder) Housing cylinder 40 (1st Outer cylinder 41 (second cylinder) cam cylinder 42 (second cylinder) inner cylinder 100 first group unit 101 first lens group 200 second group unit 201 second lens group 300 third group unit 301 3rd lens group 400 4th group unit 401 4th lens group 500 5th group unit 501 5th lens group 520 Cam ring 600 Imaging unit 700 Shutter unit

Claims (4)

A lens barrel that includes a plurality of cylinders that can be extended and retracted in a nested manner, and retracts by retracting the plurality of cylinders that have been extended.
An optical system including a plurality of lens groups housed in the lens barrel;
The lens group disposed at the rearmost position along the optical axis in a state where the plurality of cylindrical bodies are extended, and holds the lens group retracted to a position deviated from the optical axis when the lens barrel is retracted. A lens frame,
A cam ring that rotates in a plane perpendicular to the optical axis;
With
The cam ring rotates in contact with any one of the plurality of cylinders retracting along the optical axis as the lens barrel retracts, and engages a part of the lens frame. And a lens barrel having an engaging portion for retracting the lens frame. The lens barrel according to claim 1,
The plurality of lens groups include a variable power system lens group, a correction system lens group, and a focus optical system lens group, and the lens group held by the lens frame is the variable power system lens group among the plurality of lens groups. And a lens barrel other than the correction system lens group and the focus optical system lens group. The lens barrel according to claim 1 or 2,
The cam ring includes a claw protruding along the optical axis so that the cam ring is always engaged with one of the plurality of cylinders when the plurality of cylinders are extended. The lens barrel according to any one of claims 1 to 3,
An imaging device disposed at an imaging point of the optical system of the lens barrel.

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