JP2012163890A - Lens barrel and imaging apparatus - Google Patents

Abstract

A mechanism for improving the optical performance of a lens unit by removing both the tilt component and the eccentric component of the lens unit that retracts from a photographic optical axis when the lens barrel is retracted.
A lens barrel includes a base tube that rotatably supports a lens unit between a shooting position and a retracted position via a rotating shaft, and a direction of a shooting optical axis with respect to the base tube. And a holding cylinder 14 that holds the base cylinder 48. One end of the rotation shaft is fitted and fixed to the base cylinder 48, and the other end is fitted and fixed to the fitting hole 51 b of the inclination adjusting member 51. Then, the tilt adjusting member 51 is moved in the direction perpendicular to the photographing optical axis with respect to the base cylinder 48 to remove the tilt component with respect to the photographing optical axis of the lens unit 3 via the rotation shaft 50, and then the tilt adjusting member. 51 is fixed to the base cylinder 48, the base cylinder 48 is moved in a direction perpendicular to the imaging optical axis with respect to the holding cylinder 14 to remove the eccentric component with respect to the imaging optical axis of the lens unit 3, and then the base cylinder 48 is removed. It is fixed to the holding cylinder 14.
[Selection] Figure 6

Description

  The present invention relates to a zoom lens barrel mounted on an imaging apparatus such as a digital camera, and a photographing apparatus including the lens barrel.

  In a zoom lens barrel mounted on an imaging device such as a digital camera, a plurality of lens units that hold the lens are moved in the optical axis direction by the rotation of the cam barrel, and the movement in the rotational direction is restricted by the straight advance barrel. ing.

  By the way, in recent years, the lens barrel tends to increase in size due to an increase in the number of lens units and an increase in the total length of the lens barrel in response to a request for higher photographing magnification. On the other hand, there is also a demand for a thin digital camera, and it is required to shorten the dimension in the optical axis direction when the lens barrel is retracted as much as possible.

  Therefore, when the lens barrel is retracted, by retracting the remaining lens units to the retracted position with some of the lens units retracted from the imaging optical axis, the lens barrel is retracted. A technique for shortening the dimension in the optical axis direction has been proposed (Patent Document 1). In this proposal, the lens unit is driven with high accuracy by adjusting the inclination of the lens unit retracted from the photographing optical axis when the lens barrel is retracted, thereby improving the optical accuracy during photographing.

JP 2004-233916 A

  However, in Patent Document 1, the tilt component is removed by rotating the eccentric pin and tilting the rotation shaft to adjust the tilt of the lens unit retracted from the photographing optical axis. The eccentric component cannot be removed. For this reason, there is a possibility that the optical performance of the lens unit that has returned from the retracted position to the photographing optical axis during photographing is deteriorated.

  Therefore, the present invention provides a mechanism for improving the optical performance of the lens unit by removing both the tilt component and the eccentric component of the lens unit that retracts from the photographic optical axis when the lens barrel is retracted. The purpose is to do.

  In order to achieve the above object, the present invention provides a zoom lens barrel that changes an imaging magnification by moving in the optical axis direction between an imaging position and a retracted position, the lens unit, and the lens unit. A base cylinder that rotatably supports a photographing axis and a retracted position via a pivot shaft, an inclination adjusting member that is incorporated in the photographing optical axis direction with respect to the base cylinder, and holds the base cylinder A holding cylinder, and one end of the rotating shaft is fitted and fixed to the base cylinder, and the other end is fitted and fixed to the inclination adjusting member, and the inclination adjusting member is attached to the base After the adjustment to remove the tilt component with respect to the photographing optical axis of the lens unit via the rotating shaft by moving in a direction perpendicular to the photographing optical axis with respect to the tube, the tilt adjusting member is attached to the base tube. The tilt adjustment member is fixed. The base cylinder is adjusted to remove the eccentric component of the lens unit with respect to the photographing optical axis by moving the base cylinder in a direction perpendicular to the photographing optical axis with respect to the holding cylinder, and then the base cylinder is moved to the holding cylinder. It is characterized by being fixed to.

  According to the present invention, it is possible to remove both the tilt component and the eccentric component with respect to the photographing optical axis of the lens unit retracted from the photographing optical axis when the lens barrel is retracted, so that the optical performance of the lens unit can be improved. it can.

It is the external appearance perspective view which looked at the digital camera which is an example of the embodiment of the imaging device of the present invention from the front side. FIG. 2 is a view of the digital camera shown in FIG. 1 as viewed from the back side. It is a block diagram for demonstrating the control system of a digital camera. It is sectional drawing in the state which has a lens-barrel in a retracted position. It is sectional drawing in the state which has a lens-barrel in a wide position. It is a disassembled perspective view which shows the relationship between an inner side linear cylinder, a base cylinder, an inclination adjustment member, and a 3rd lens unit. (A) is the figure which looked at the state which incorporated the inclination adjustment member and the 3rd lens unit in the base cylinder from the to-be-photographed object side, (b) is the figure which fractured | ruptured a part of right view of FIG. It is. It is the perspective view seen from the diagonally right upper part of Fig.7 (a). It is the figure which looked from the to-be-photographed object side of the imaging | photography optical axis direction the state which incorporated the base pipe | tube in the inner side straight advance cylinder after the inclination adjustment of the 3rd lens unit was completed. It is the perspective view seen from the diagonally upper right of FIG.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of an external appearance of a digital camera as an example of an embodiment of an imaging apparatus according to the present invention, and FIG. 2 is a view of the digital camera shown in FIG.

  As shown in FIGS. 1 and 2, the digital camera 15 according to the present embodiment includes a finder 20, an auxiliary light source 19, a strobe 21, and a lens barrel 30 used when performing photometric distance measurement on the front side. ing. The lens barrel 30 is of a zoom type that moves in the optical axis direction between the photographing position and the retracted position to change the photographing magnification.

  On the top surface of the digital camera 15, a release button 16, a power switch button 18, and a zoom switch 17 are arranged. Further, as shown in FIG. 2, operation button groups 24 to 29, a display 23 such as an LCD, and a viewfinder eyepiece 22 are disposed on the back side of the digital camera 15.

  FIG. 3 is a block diagram for explaining a control system of the digital camera 15. As shown in FIG. 3, a CPU 46, a ROM 45, a RAM 47, a release button 16, operation button groups 24 to 29, and a display 23 are connected to the bus 44. Further, the power switch button 18, zoom switch 17, memory 40, compression / decompression unit 41, memory card drive 42, and drive circuit 43 are connected to the bus 44.

  Connected to the drive circuit 43 are a zoom mechanism 31 for zooming the lens barrel 30, a focus drive mechanism 32 for driving the focus lens 5, a shutter drive mechanism 34 for driving the shutter 33, and an aperture drive mechanism 36 for driving the aperture 35. Is done.

  The drive circuit 43 is connected to the image sensor 11 such as a CCD sensor or a CMOS sensor and the flash 21. Drive of each unit connected to the drive circuit 43 is controlled via the drive circuit 43 based on a signal from the CPU 46.

  The ROM 45 stores various control programs and the like, and the RAM 47 stores data necessary for the various control programs. The analog signal processing unit 37 performs analog processing on the image data output from the image sensor 11 and outputs the analog data to the A / D conversion unit 38.

  The A / D conversion unit 38 converts analog data captured from the image sensor 11 into digital data and outputs the digital data to the digital signal processing unit 39. The digital signal processing unit 39 performs predetermined processing on the digital data converted by the A / D conversion unit 38 and outputs the processed data to the memory 40 as image data.

  The image data stored in the memory 40 is subjected to compression processing such as JPEG or TIFF by the compression / decompression unit 41, and then output to and stored in a memory card attached to the memory card drive 42.

  Further, the image data stored in the memory 40 or the image data stored in the memory card drive 42 can be expanded by the compression / decompression unit 41 and then displayed on the display 23 via the bus 44.

  Next, the lens barrel 30 will be described with reference to FIGS.

  4 is a cross-sectional view of the lens barrel 30 in the retracted position, and FIG. 5 is a cross-sectional view of the lens barrel 30 in the wide position.

  As shown in FIGS. 4 and 5, the lens barrel 30 includes a first lens unit that holds the first group lens, a second lens unit 2 that holds the second group lens, and a third lens that holds the third group lens. Unit 3 is provided. The lens barrel 30 includes a fourth lens unit 4 that holds a fourth group lens, and a fifth lens unit 5 that holds a fifth group lens. The fifth lens unit of the fifth lens unit 5 is a focus lens. It is said that.

  Here, in this embodiment, as shown in FIG. 4, when the lens barrel 30 is retracted to the retracted position, the third lens unit 3 that is a part of the plurality of lens units 1 to 5 is removed from the photographing optical axis. The lens barrel 30 is retracted radially outward to shorten the dimension in the optical axis direction when the lens barrel 30 is retracted. A mechanism for retracting the third lens unit 3 from the photographing optical axis will be described later with reference to FIGS.

  The element holder 12 holds the imaging element 11, and the fixed cam cylinder 10 is disposed on the subject side of the element holder 12. The element holder 12 is provided with a retracting lever (not shown) for retracting the third lens unit 3 from the photographing optical axis when the lens barrel 30 is retracted.

  A fixed cam groove 10a is formed in the inner peripheral portion of the fixed cam cylinder 10, and a follower pin of the second movable cam cylinder 8 that follows the fixed cam groove 10a is cam-engaged with the fixed cam groove 10a. When the second movable cam cylinder 8 is driven to rotate, the follower pin moves in the optical axis direction while rotating with respect to the fixed cam cylinder 10 following the fixed cam groove 10a.

  A second rectilinear cylinder 9 is disposed on the inner peripheral portion of the second movable cam cylinder 8, and the second rectilinear cylinder 9 is bayonet-coupled so as to be relatively rotatable with respect to the second movable cam cylinder 8, 2 Moves in the optical axis direction together with the moving cam cylinder 8. A key groove is formed on the outer peripheral portion of the second rectilinear cylinder 9 to be coupled to the rectilinear key 10b provided on the inner peripheral portion of the fixed cam cylinder 10, whereby the rotation of the second rectilinear cylinder 9 is restricted. The

  Further, a second cam groove 8a is formed in the inner peripheral portion of the second movable cam cylinder 8, and a follower pin of the first rectilinear cylinder 7 following the second cam groove 8a is formed in the second cam groove 8a. Engage with cam.

  A first moving cam cylinder 6 is arranged on the outer peripheral side of the first rectilinear cylinder 7, and the first moving cam cylinder 6 is bayonet-coupled to the first rectilinear cylinder 7 so as to be rotatable. The first rectilinear cylinder 7 has a key groove that is coupled to a rectilinear key provided in the second rectilinear cylinder 9, whereby the first rectilinear cylinder 7 is moved in the second state in a state where the rotation is restricted. Due to the cam engagement with the cam barrel 8, it is possible to move relative to the second movable cam barrel 8 in the optical axis direction.

  The first moving cam cylinder 6 is key-coupled to the second moving cam cylinder 8, and moves in the optical axis direction together with the first rectilinear cylinder 7 while rotating as the second moving cam cylinder 8 rotates. ing. A cam groove is formed in the inner peripheral portion of the first movable cam cylinder 6, and the follower pin of the first lens unit 1 that follows the cam groove is cam-engaged with the cam groove.

  Accordingly, the first lens unit 1 moves in the optical axis direction by the rotation of the first moving cam cylinder 6. When the first lens unit 1 moves in the optical axis direction, the first lens unit 1 is key-coupled to the first rectilinear cylinder 7 and its rotation is restricted.

  An inner cam cylinder 13 is disposed on the inner peripheral side of the second movable cam cylinder 8, and an inner rectilinear cylinder 14 is disposed on the inner peripheral side of the inner cam cylinder 13.

  The inner rectilinear cylinder 14 is bayonet-coupled to the inner cam cylinder 13 so as to be rotatable. A second cam groove 8b is formed in the inner peripheral portion of the second movable cam cylinder 8, and a follower pin of the inner rectilinear cylinder 14 that follows the second cam groove 8b is cammed in the second cam groove 8b. Engage.

  The inner rectilinear cylinder 14 has a key groove that is coupled to a rectilinear key provided in the second rectilinear cylinder 9, whereby the inner rectilinear cylinder 14 is in a state in which rotation is restricted, and the second movable cam cylinder. It becomes possible to move relative to the second moving cam cylinder 8 in the optical axis direction by cam engagement with the cam 8.

  The inner cam cylinder 13 is key-coupled to the second moving cam cylinder 8 and moves in the optical axis direction together with the inner rectilinear cylinder 14 while rotating as the second moving cam cylinder 8 rotates. In addition, a cam groove that the follower pin 2a of the second lens unit 2 follows is formed on the outer peripheral portion of the inner cam tube 13, and the third lens unit 3 and the fourth lens are formed on the inner peripheral portion of the inner cam tube 13. A cam groove that each follower pin of the unit 4 follows is formed.

  Thereby, the second lens unit 2, the third lens unit 3, and the fourth lens unit 4 are moved in the optical axis direction by the rotation of the inner cam cylinder 13. The rotation of the third lens unit 3 and the fourth lens unit 4 is restricted by the inner rectilinear cylinder 14. The rotation of the second lens unit 2 is regulated by being guided straight in the optical axis direction by the first rectilinear cylinder 7 and the first lens unit 1. Specifically, the second lens unit 2 is switched from a rectilinear guide by the first rectilinear cylinder 7 to a rectilinear guide by the first lens unit 1 while moving from the wide position to the tele position.

  Next, a mechanism for retracting the third lens unit 3 from the photographing optical axis when the lens barrel 30 is retracted to the retracted position will be described with reference to FIGS.

  FIG. 6 is an exploded perspective view showing the relationship among the inner rectilinear cylinder 14, the base cylinder 48, the tilt adjusting member 51, and the third lens unit 3. 7A is a view of the state in which the tilt adjusting member 51 and the third lens unit 3 are incorporated in the base cylinder 48, as viewed from the subject side in the photographing optical axis direction, and FIG. 7B is a view of FIG. 7A. FIG. 8 is a perspective view of a part of the right side view cut away, and FIG. 8 is a perspective view as viewed from the upper right side of FIG.

  As shown in FIGS. 6 to 8, the outer periphery of the third lens unit 3 is provided with an arm portion 3b extending outward in the radial direction, and an imaging light is provided at the extending end of the arm portion 3b. A cylindrical support cylinder 3a having an axis parallel to the axis is disposed.

  A torsion spring 49 is extrapolated on the outer periphery of the support cylinder 3a. In this state, the support cylinder 3a is rotatably incorporated with respect to the base cylinder 48. In the assembled state, the third lens unit 3 is urged toward the photographing position by the torsion spring 49 and is arranged concentrically with the axis of the base tube 48. Therefore, when the third lens unit 3 is rotated from the photographing position to the retracted position, the third lens unit 3 is rotated against the urging force of the torsion spring 49 with the axis of the support cylinder 3a as a fulcrum.

  A rotating shaft 50 is inserted into the hollow portion of the support cylinder 3a from the subject side, and one end 50a on the image plane side of the rotating shaft 50 is fitted into a hole 48e formed in the base cylinder 48. Fixed. The third lens unit 3 is rotatably supported with respect to the base cylinder 48 via a rotation shaft 50 inserted into the support cylinder 3a.

  The other end 50 b on the subject side of the rotation shaft 50 protrudes from the base tube 48 toward the subject side through a hole 48 c formed in the base tube 48. The inner diameter of the hole 48c is formed larger than the outer diameter of the rotation shaft 50, and the radial space between the hole 48c and the rotation shaft 50 is inclined with respect to the photographing optical axis of the third lens unit 3. It is an adjustment space for adjusting.

  A hole 51b formed in the tilt adjusting member 51 is fitted and fixed to the end 50b of the rotation shaft 50 protruding from the base tube 48 toward the subject. In addition to the hole 51 b, a plurality of holes 51 a are formed in the tilt adjusting member 51, and the holes 51 a are extrapolated to a shaft portion 48 d protruding from the base cylinder 48. The inner diameter of the hole 51a is larger than the outer diameter of the shaft portion 48d, and the radial space between the hole 51 and the shaft portion 48d corresponds to the adjustment space described above.

  Then, the tilt adjusting member 51 is moved with respect to the base tube 48 along the direction orthogonal to the photographing optical axis, thereby adjusting the tilt of the rotation shaft 50 and, consequently, the tilt of the third lens unit 3, An inclination component with respect to the photographing optical axis of the lens unit 3 is removed. Then, the tilt adjustment of the third lens unit 3 is completed by fixing the fixing portion 48a of the base tube 48 and the tilt adjusting member 51 with an ultraviolet adhesive or the like.

  In the present embodiment, after the tilt adjustment of the third lens unit 3 is completed, when the base tube 48 is assembled into the inner rectilinear tube 14, the eccentric adjustment with respect to the photographing optical axis of the third lens unit 3 is performed.

  FIG. 9 is a view of the state in which the base cylinder 48 is incorporated into the inner rectilinear cylinder 14 after the tilt adjustment of the third lens unit 3 is completed, viewed from the subject side in the photographing optical axis direction, and FIG. It is the perspective view seen from.

  As shown in FIGS. 9 and 10, the base cylinder 48 in which the tilt adjustment of the third lens unit 3 has been completed is incorporated on the inner peripheral side of the inner rectilinear cylinder 14. In this state, the decentering adjustment of the third lens unit 3 is performed by moving the base tube 48 along the direction orthogonal to the optical axis with respect to the inner rectilinear tube 14, and the photographing optical axis of the third lens unit 3. Eccentric component with respect to is removed. Then, the eccentric adjustment is completed by fixing the fixing portion 14a of the inner rectilinear cylinder 14 and the fixing portion 48b of the base cylinder 48 via an ultraviolet adhesive or the like. Here, the inner rectilinear cylinder 14 corresponds to an example of the holding cylinder of the present invention.

  As described above, in this embodiment, since both the tilt component and the eccentric component of the lens unit that retracts from the photographic optical axis when the lens barrel is retracted can be removed, the optical performance of the lens unit. Can be improved.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

3 Third lens unit 14 Inner rectilinear cylinder 48 Base cylinder 50 Rotating shaft 51 Tilt adjusting member

Claims (2)

A zoom type lens barrel that moves in the optical axis direction between the shooting position and the retracted position to change the shooting magnification,
A lens unit;
A base tube that rotatably supports the lens unit between a shooting position and a retracted position via a rotation shaft;
An inclination adjusting member incorporated in the direction of the photographing optical axis with respect to the base tube;
A holding cylinder for holding the base cylinder,
The rotating shaft has one end fitted and fixed to the base cylinder, and the other end fitted and fixed to the tilt adjusting member.
After adjusting the tilt adjustment member to remove the tilt component with respect to the photographing optical axis of the lens unit via the rotating shaft by moving the tilt adjusting member in a direction perpendicular to the photographing optical axis with respect to the base tube, Fix the tilt adjustment member to the base tube,
After adjusting the removal of the eccentric component with respect to the photographing optical axis of the lens unit by moving the base cylinder to which the tilt adjusting member is fixed in a direction perpendicular to the photographing optical axis with respect to the holding cylinder, A lens barrel, wherein a base barrel is fixed to the holding barrel. An imaging apparatus including a zoom lens barrel that moves in the optical axis direction between an imaging position and a retracted position to change an imaging magnification,
An imaging apparatus comprising the lens barrel according to claim 1 as the lens barrel.

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