JP6150505B2 - Lens barrel and imaging device having the same - Google Patents

Description

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

  There has been proposed an imaging apparatus that transitions between an accommodation state in which the lens groups are accommodated by narrowing the interval between the lens groups of the lens barrel and an imaging state in which the lens groups are arranged at intervals capable of imaging. In such a lens barrel of the imaging device, each lens group is extended to a predetermined position on the subject side in the shooting state, and in order to improve the portability of the imaging device in the retracted state, each lens group is on the imaging surface side. It is retracted and is generally called a retractable lens barrel. Further, the retractable lens barrel is generally a zoom lens barrel in which the focal length of the lens is variable in the photographing state.

  The retractable lens barrel is required to be as short as possible in the direction of the optical axis when it is retracted in order to enhance the retractability. On the other hand, the amount of change in focal length, the so-called zoom magnification, must be increased to support various shooting scenes. It is done. Therefore, the amount of displacement between the storage state of the lens barrel and the photographing state is increasing. In order to cope with this large amount of displacement, there has been proposed a lens barrel in which the length of the movable barrel extended in the optical axis direction is increased, or a plurality of movable barrels are provided so that the barrel is a multistage feeding system. ing.

  However, the amount of displacement between the housed state and the photographing state tends to increase, and the accommodation of the lens barrel is impaired when the moving tube is lengthened with respect to the increase in the amount of displacement. Moreover, in the response | compatibility which increases the number of a movement cylinder, while a lens-barrel structure becomes complicated, a lens-barrel diameter will increase.

  Patent Document 1 discloses a lens barrel that reduces the amount of movement of the movable barrel and reduces the size of the lens barrel. In this lens barrel, a predetermined lens group is extended in the optical axis direction by using a driving force of a spring of a lens barrier that protects the tip of the lens. As a result, it is possible to prevent the lens barrel structure from becoming greatly complicated and the diameter of the lens barrel from increasing, and to increase the amount of displacement of the optical system.

JP 2007-248608 A

  In the lens barrel disclosed in Patent Document 1, a cam for extending a lens group is provided in a barrier opening / closing force transmitting means provided in a moving cylinder that holds a first lens to be extended. For this reason, the lens group extension position is determined by the two parts of the barrier opening / closing force transmission means and the movable cylinder, and the lens group extension position varies due to dimensional errors due to manufacturing variations of each part. Further, there is a problem that the extended position of the lens group is not stable due to the backlash between the barrier opening / closing force transmitting means and the movable cylinder.

  The optical performance of the lens barrel deteriorates due to a positional shift in the optical axis direction, a positional shift from the optical axis, and a tilt of a plurality of lenses constituting the lens barrel. The degree to which the optical performance deteriorates due to positional deviation or tilting differs depending on each single lens. In general, this degree is position sensitivity with respect to positional deviation in the optical axis direction, and deviation with respect to positional deviation from the optical axis. The core sensitivity is called the fall sensitivity. In recent years, due to the miniaturization of the lens barrel, the power of each lens constituting the lens barrel tends to increase, which causes an increase in sensitivity. A lens barrel structure in which the extension position of the lens group varies or is not stable cannot cope with such a highly sensitive optical system.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens barrel that can increase the reproducibility of the extended position of a lens group and can be applied to a highly sensitive optical system.

A lens barrel according to an embodiment of the present invention includes a holding member that holds a lens, a member that shields the lens, and a shielding member that transitions between a shielding state that shields the lens and an exposed opening state. A driving member that drives the shielding member to transition to the shielding state or the opening state; a first urging means that urges the driving member so that the shielding member is in the opening state; and the holding member. A lens holding unit that holds the drive member and the first urging means while holding the drive member so as to be able to advance and retreat by a cam engagement, and the urging force of the first urging means holds the drive member. Is transmitted to the holding member through the second member, so that the holding member is displaced in the optical axis direction in accordance with the cam engagement with the lens holding unit, and urges the holding member in the optical axis direction. Energizer of With the door, the second biasing means generates a biasing force to separate or approach each other in the optical axis direction between the drive member and the holding member.

  According to the lens barrel of this embodiment, without increasing the length in the optical axis direction when the lens barrel is retracted, it is possible to cope with an increase in the amount of displacement of the lens, and to improve the reproduction position accuracy of the lens group, Compatible with highly sensitive optical systems.

1 is an exploded perspective view of a lens barrel according to the present invention. It is sectional drawing in the retracted state of the lens-barrel which concerns on this invention. It is sectional drawing in the imaging | photography state of the lens-barrel which concerns on this invention. It is a disassembled perspective view of a 1st lens group unit. It is a front view of a 1st lens group unit. It is a disassembled perspective view of a barrier drive ring and a movable cam cylinder. It is an example of sectional drawing of the 1st lens group unit. It is a figure explaining the function of a resin spring. It is an example of sectional drawing of the 1st lens group unit which hold | maintains a 1st lens group so that eccentricity adjustment is possible.

  FIG. 1 is an exploded perspective view of the lens barrel of the present embodiment. 2 is a cross-sectional view of the imaging apparatus including the lens barrel shown in FIG. 1 when the lens barrel shown in FIG. 1 is retracted. FIG. 3 is a cross-sectional view of the imaging apparatus including the lens barrel shown in FIG. 1 when the lens barrel shown in FIG. 1 is in a shooting state. Note that the imaging apparatus of the present embodiment is a digital camera and includes the lens barrel shown in FIG.

  As shown in FIGS. 1 to 3, the lens barrel 1 has four optical groups. The first lens group unit 10 holds the first lens group 11. Similarly, the second lens group unit 20 holds the second lens group 21. The third lens group unit 30 holds the third lens group 31. The first lens group unit 10 to the third lens group unit 30 are driven in the optical axis direction in conjunction with each other and driven in by a motor 52 described later. The third lens group unit 30 includes an aperture and a shutter unit. The fourth lens group unit 40 holds the fourth lens group 41. Further, the AF motor unit 53 supports the fourth lens group unit 40 so as to be movable in the optical axis direction independently of the other optical lens groups.

  Although the details will be described later, the lens barrel 1 has a three-stage configuration that can be expanded and contracted in the optical axis direction, and the total length of the lens barrel can be changed between photographing and retracting. The lens barrel 1 is driven by a motor 52 and an AF motor unit 53 so that each lens group is in a predetermined position at the time of shooting, and forms a subject image. An image sensor 50 is placed on the imaging plane, and image information is acquired by photoelectric conversion. The image sensor holder 51 holds the image sensor 50. The image sensor holder 51 holds the motor 52 and the AF motor unit 53 in addition to the image sensor 50, and supports the fourth lens group unit 40 so as to be movable in the optical axis direction.

  Next, each stage of the lens barrel constituting the lens barrel 1 will be described. The fixed cylinder 60 is a cylindrical part that is held by the imaging element holder 51. The fixed cylinder 60 is fixed to an image pickup apparatus main body (not shown) together with the image pickup element holder 51 with screws or the like.

  The rotary cylinder 70 that is the first stage of the lens barrel has a cylindrical shape, and three cam pins 71 are equally provided in the circumferential direction at the same position in the optical axis direction on the outer surface, and a partial gear 72 is provided. ing. On the inner surface of the fixed cylinder 60, cam grooves 61 are provided in which the three cam pins 71 are cam-engaged. The rotating cylinder 70 is supported by the fixed cylinder 60 by cam engagement of the three cam pins 71 and the cam groove 61.

  The fixed cylinder 60 includes an output gear 62. The driving force of the motor 52 is transmitted to the output gear 62 via the gear train 54. The output gear 62 meshes with the partial gear 72, and the rotating cylinder 70 is rotated by the motor 52. The rotating cylinder 70 is displaced in the optical axis direction following the cam locus of the cam groove 61 by the rotation of the rotating cylinder 70.

  The rectilinear plate 73 is a part obtained by press-working a metal plate, and is rotatably engaged with the rotary cylinder 70 by a bayonet structure. The rectilinear key 74 is provided at three equal portions on the outer peripheral portion of the rectilinear plate 73 and engages with three key grooves 63 provided on the inner surface of the fixed cylinder 60 in parallel with the optical axis. As a result, the rectilinear plate 73 is displaced together without rotating in accordance with the displacement of the rotating cylinder 70 in the optical axis direction.

  The moving cylinder 80 has a cylindrical shape, and six cam pins 81 are provided on the outer surface of the moving cylinder 80 equally in the circumferential direction and at the same position in the optical axis direction. On the inner surface of the rotating cylinder 70, cam grooves 75 are provided in which the cam pins 81 are cam-engaged. The movable cylinder 80 is supported by the rotary cylinder 70 by cam engagement of the six cam pins 81 and the cam grooves 75.

  The rectilinear plate 73 has a rectilinear projection 76 that extends in parallel with the optical axis formed by bending a metal plate by press working, and the rectilinear projection 76 engages with a gripping portion 82 provided on the movable cylinder 80. Accordingly, the movable cylinder 80 is guided so as to advance straight in the optical axis direction, and is displaced in the optical axis direction following the cam locus of the cam groove 75 by the rotation of the rotary cylinder 70.

  The moving cam cylinder 83 has a cylindrical shape and is rotatably engaged with the moving cylinder 80 by a bayonet structure. Two rectilinear keys 84 are provided on the outer peripheral portion of the moving cam cylinder 83 in a substantially point-symmetric manner with respect to the optical axis. Each rectilinear key 84 engages with two key grooves 77 provided on the inner surface of the rotary cylinder 70 in parallel with the optical axis. As a result, the movable cam cylinder 83 rotates together with the rotary cylinder 70 and is displaced in the optical axis direction together with the movable cylinder 80 by bayonet coupling.

  The first lens group unit 10 is directed to the inner surface of the lens barrel (in the direction orthogonal to the optical axis, the direction toward the optical axis). Prepare for. On the other hand, the movable cam cylinder 83 has a cam groove 85 on the outer surface for engaging each cam pin of the first lens group unit 10. The first lens group unit 10 is supported on the movable cam cylinder 83 by cam engagement of the three cam pins and the cam groove 85.

  The rectilinear cylinder 86 has a cylindrical shape, and is rotatably engaged with the movable cam cylinder 83 by a bayonet structure. On the other hand, the rectilinear plate 73 has a rectilinear projection 78 that extends in parallel with the optical axis formed by bending a metal plate by press working. The rectilinear protrusion 78 engages with a grip portion 87 provided on the outer surface of the rectilinear cylinder 86. Thereby, the rectilinear cylinder 86 is guided so as to advance straight in the optical axis direction, and is displaced in the optical axis direction together with the movable cam cylinder 83.

  A rectilinear key 88 is provided on the outer peripheral portion of the rectilinear cylinder 86. The rectilinear key 88 is fitted into a key groove provided on the inner surface of the first lens group unit 10 and extending parallel to the optical axis. Thereby, the first lens group unit 10 is guided so as to advance straight in the optical axis direction, and is displaced in the optical axis direction following the cam locus of the cam groove 85 by the rotation of the movable cam cylinder 83.

  The second lens group unit 20 includes three cam pins 22 that are equally divided in the circumferential direction and at the same position in the optical axis direction toward the outside. On the other hand, the movable cam cylinder 83 is provided with cam grooves 89 on the inner surface where the cam pins 22 are cam-engaged. The second lens group unit 20 is supported by the movable cam cylinder 83 by cam engagement of the three cam pins 22 and the cam groove 89.

  The rectilinear cylinder 86 includes a notch 90 extending in parallel with the optical axis penetrating the inner and outer surfaces of the cylinder. On the other hand, the second lens group unit 20 includes a key 23 that fits into the notch 90. Accordingly, the second lens group unit 20 is guided so as to advance straight in the optical axis direction, and is displaced in the optical axis direction following the cam locus of the cam groove 89 by the rotation of the movable cam cylinder 83.

  The third lens group unit 30 includes three cam pins 32 that are equally divided in the circumferential direction toward the outer side and are provided at the same position in the optical axis direction. On the other hand, the movable cam cylinder 83 is provided with cam grooves 91 on the inner surface where the cam pins 32 engage with each other. The movable cam cylinder 83 supports the third lens group unit 30 by cam engagement of the three cam pins 32 and the cam groove 91.

  The rectilinear cylinder 86 includes a notch 92 that extends parallel to the optical axis penetrating the inner and outer surfaces of the rectilinear cylinder 86. On the other hand, the third lens group unit 30 has a key 33 that fits into the notch 92. Thereby, the third lens group unit 30 is guided so as to advance straight in the optical axis direction, and is displaced in the optical axis direction following the cam locus of the cam groove 91 by the rotation of the movable cam cylinder 83.

  As described above, the first lens group unit 10 to the third lens group unit 30 are supported by the rotation of the rotary cylinder 70, that is, by the motor 52 so as to be displaceable in the optical axis direction. The displacement amount of each unit is such that the cam groove 61 provided in the fixed cylinder 60, the cam groove 75 provided in the rotary cylinder 70, and the cam groove corresponding to each lens group unit provided in the movable cam cylinder 83 are provided. Add up.

  The total cam locus of each cam groove in the lens barrel 1 is a zoom cam locus that defines the displacement of each lens group unit for the zoom optical system to uniformly change its focal length. The lens barrel 1 is a collapsible zoom barrel having a collapsible cam for housing each lens group unit. Thereby, the lens barrel 1 can shift the optical system from the retracted state shown in FIG. 2 to the photographing state shown in FIG. 3 by the rotation of the motor 52. On the other hand, since the fourth lens group unit 41 can adjust the focus by the displacement in the optical axis direction, the subject image formed on the imaging surface can be formed by controlling the AF motor unit 53. is there.

  FIG. 4 is an exploded perspective view of the first lens group unit. A lens barrier mechanism and a first lens displacement mechanism included in the first lens group unit 10 will be described with reference to FIG.

  The cover 12 includes an opening 121 through which the photographing optical path of the present optical system passes. In the lens barrel 1, the shaft 131 is loosely fitted in the hole 141 provided in the first lens group holder 14 so that the two barrier blades 13 are arranged symmetrically with respect to the optical axis. The barrier blade 13 transitions between a closed state that covers all of the opening 121 and an open state that retreats from the opening 121. That is, the barrier blade is a shielding member that shields the lens, and transitions between a shielding state that shields the lens and an exposed opening state. The cover 12 is fixed to the first lens group holder 14 by adhesion or double-sided tape.

  The barrier drive ring 15 is a hollow ring-shaped component, and is loosely fitted to the first lens group holder 14 so as to be rotatable about the optical axis, and the movement in the optical axis direction is restricted by the bayonet structure. In addition, an opening spring 16 that is a tension spring is attached to the barrier drive ring 15 between the spring hooking portion 142 of the first lens group holder 14, and the barrier drive ring 15 faces the lens barrel 1 in front. Rotation is urged in the clockwise direction when viewed from the side. That is, the opening spring 16 functions as a first biasing unit that biases the barrier drive ring 15 so that the barrier blades 13 are in an open state.

  The barrier drive ring 15 includes a protrusion 151 protruding in the optical axis direction. Further, the barrier blade 13 includes a working surface 132 with which the protrusion 151 comes into contact. By rotating the barrier drive ring 15 in the clockwise direction by the opening spring 16, the protrusion 151 presses the action surface 132, so that the barrier blade 13 rotates in the counterclockwise direction. In other words, the barrier drive ring 15 functions as a drive member that drives the barrier blade 13 to change the barrier blade 13 to a shielding state or an open state.

  FIG. 5 is a front view of the first lens group unit. FIG. 5A shows the opened state of the barrier blade 13, and FIG. 5B shows the closed state of the barrier blade 13. As illustrated in FIG. 5A, the barrier blade 13 rotates counterclockwise by the pulling force of the opening spring 16, and the barrier is opened from the opening 121.

  FIG. 6 is an exploded perspective view of the barrier drive ring and the movable cam cylinder. With reference to FIG. 6, the operation | movement to the closed state of the barrier blade | wing 13 is demonstrated. The barrier drive ring 15 is provided with a protrusion 155 that extends toward the imaging surface side in the optical axis direction. The protrusion 155 passes through the hole 148 of the first lens group holder 14. On the other hand, the movable cam cylinder 83 is provided with a surface 93 in which a part of the cylinder is cut out and parallel to the optical axis.

  The lens barrel 1 transitions from the photographing state to the retracted state by the rotation of the movable cam barrel 83 in the counterclockwise direction when viewed from the front. The first lens group unit 10 and the moving cam cylinder 83 approach each other during the transition of the lens barrel 1 from the photographing state to the retracted state. When the first lens group unit 10 and the moving cam cylinder 83 approach each other, the protrusion 155 overlaps the notch of the moving cam cylinder 83 in the optical axis direction. The protrusion 155 includes an action surface 153 that extends in the optical axis direction in contact with the surface 93 of the movable cam cylinder 83. When the first lens group unit 10 and the movable cam cylinder 83 approach each other, the surface 93 and the action surface 153 come into contact with the rotation of the movable cam cylinder 83. Further, when the movable cam cylinder 83 rotates counterclockwise, the barrier drive ring 15 rotates counterclockwise in the same manner as the movable cam cylinder 83 against the force of the opening spring 16.

  Returning to FIG. 4, a closing spring 17, which is a tension spring, is attached to the barrier blade 13 between the barrier blade 13 and the barrier driving ring 15. For this reason, when the barrier drive ring 15 rotates counterclockwise, the protrusion 151 also moves counterclockwise, and the barrier blade 13 rotates clockwise as viewed from the front by the closing spring 17. As the moving cam cylinder 83 rotates counterclockwise, the protrusion 151 is finally separated from the action surface 132 of the barrier blade 13 as shown in FIG. It comes into contact with the mating surfaces and is in a closed state that covers the opening 121.

  Returning to FIG. 4, the description of the configuration of the first lens group unit 10 will be continued. The lens holder 111 holds the first lens group 11. The rotary moving ring 18 is a hollow ring-shaped part, and holds the lens holder 111 by bonding. Therefore, the rotary moving ring 18 functions as a holding member that holds the lens.

  FIG. 7 is an example of a cross-sectional view of the first lens group unit. The outer periphery of the lens holder 111 is provided with a spherical surface 117 having a center on the optical axis. On the other hand, the rotary moving ring 18 has a conical surface 184 having a vertex on the optical axis. The spherical surface 117 is disposed so as to abut on the conical surface 184, so that the lens holder 111 is supported so as to be tiltable with respect to the rotational moving ring 18 with the center of the spherical surface 117 as the center of rotation.

  The lens holder 111 has a partial flange 112 on the outer periphery thereof. On the other hand, the rotary moving ring 18 has a pocket 187 that encloses the flange 112. With these structures, the first lens group 11 is put in the pocket 184 with an adhesive appropriately tilted in an optimal tilt amount and tilt direction in order to exhibit the desired optical performance of the lens barrel 1. It can be adhesively fixed.

  The present invention is not limited to the optical system for adjusting the tilt of the first lens group 11. The present invention can also be applied to an optical system that decenters the first lens group 11. FIG. 9 is an example of a cross-sectional view of a first lens group unit that holds the first lens group 11 so that the eccentricity can be adjusted. The lens holder 113 is provided with a partial flange 112 on the outer periphery thereof. The rotational moving ring 19 has a surface orthogonal to the optical axis with which the flange 112 abuts, and the lens holder 113 is supported so as to be movable on this surface. As a result, the first lens group 11 can be bonded and fixed in a state where the eccentricity is optimally adjusted as appropriate in order to exhibit the desired optical performance of the lens barrel. That is, the pocket 187 functions as an adhesive application unit for holding the lens in an eccentric state or in a tilted state.

  As shown in FIG. 4, three sets of two cam pins 181 extend outwardly from the rotary moving ring 18 at a predetermined interval in the optical axis direction. The three sets of cam pins 181 are provided on the outer surface (outer periphery) of the rotary moving ring 18 at equal positions in the optical axis direction evenly in the circumferential direction. On the other hand, cams 143 with which the cam pins 181 are cam-engaged are provided on the inner surface of the first lens group holder 14, and the rotary ring 18 is moved by the cam engagement between the three cam pins 181 and the cam 143. Supported by one lens group holder 14. That is, the first lens group holder 14 functions as a lens holding unit that holds the rotary moving ring 18 so that it can advance and retreat in the optical axis direction by cam engagement, and holds the barrier drive ring 15 and the opening spring 16.

  The rotation ring 18 is provided with a protrusion 182 extending in the optical axis direction. On the other hand, the barrier drive ring 15 is provided with a hole 152 extending in the optical axis direction with which the protrusion 182 is engaged. Due to the engagement between the protrusion 182 and the hole 152, the rotary moving ring 18 rotates with the rotation of the barrier drive ring 15.

  A regulating projection 183 is provided on the outer periphery of the rotary moving ring 18. The first lens group holder 14 is provided with a regulating surface 144 against which the regulating projection 183 comes into contact with the rotation of the rotary moving ring 18. The rotation of the rotational movement ring 18 is regulated by the regulation projection 183 coming into contact with the regulation surface 144 by the clockwise rotation of the rotational movement ring 18 as viewed from the front of the lens barrel.

  As described above, the barrier drive ring 15 is urged to rotate in the clockwise direction when the lens barrel 1 is viewed from the front by the opening spring 16 in the opened state of the barrier blade 13. Thereby, together with the barrier drive ring 15 via the protrusion 182, the rotational movement ring 18 also rotates in the clockwise direction until the restriction protrusion 183 and the restriction surface 144 come into contact with each other. The barrier drive ring 15 is pressed against the movable cam cylinder 83 in the closed state of the barrier blade 13, and is determined by the stop phase when the movable cam cylinder 83 is retracted, with the barrier blade 13 shown in FIG. Stop in contact.

  The cam 143 includes a shelf cam (first cam) 145 that is not displaced in the optical axis direction, a shelf cam (second cam) 146 that is not displaced in the optical axis direction on the subject side of the shelf cam 145, and A shelf cam 145 and a connecting cam (third cam) 147 connecting the shelf cam 146 are provided. The restriction surface 144 is disposed so as to contact the restriction protrusion 183 when the cam pin 181 is cam-engaged with the shelf cam 146. In the photographing state of the lens barrel 1, the barrier blade 13 is in an open state. At this time, the rotationally moving ring 18 is urged to rotate clockwise by the opening spring 16 via the barrier drive ring 15, and the cam pin 181 is engaged with the shelf cam 146. FIG. 7B shows a state in which the cam pin 181 of the rotary moving ring 18 is cam-engaged with the shelf cam 146.

  Next, the operation of the rotary moving ring 18 according to the transition of the lens barrel 1 from the photographing state to the retracted state will be described. When the lens barrel 1 changes to the retracted state, the moving cam cylinder 83 is rotated counterclockwise by the motor 52. As a result, the surface 93 of the movable cam cylinder 83 and the action surface 153 of the barrier drive ring 15 start to contact, and the barrier drive ring 15 also starts to rotate counterclockwise. Accordingly, the rotary moving ring 18 rotates counterclockwise and reaches the shelf cam 145 from the shelf cam 146 through the connecting cam 147.

  FIG. 7A shows a state in which the cam pin 181 of the rotary moving ring 18 is cam-engaged with the shelf cam 145. In this state, the rotational moving ring 18 moves to the optical axis direction imaging surface side by the difference in the optical axis direction between the shelf cam 145 and the shelf cam 146. The first lens group 11 fixed to the rotary moving ring 18 also moves to the optical axis direction imaging surface side, and the barrier blade 14 enters the space after the movement. With the configuration described above, the first lens group 11 moves toward the subject side in the optical axis direction at the time of shooting, so that the displacement amount of the first lens group 11 can be enlarged with the three-stage barrel configuration.

  The rotary moving ring 18 is provided with resin springs 185 equally at three places. And as shown in FIG. 8, each resin spring 185 is equipped with the ball | bowl R186 at the front-end | tip. On the other hand, the barrier drive ring 15 includes a contact portion 153 with the sphere R186 at a position overlapping the sphere R186 when viewed from the optical axis direction.

  FIG. 8 is a diagram illustrating the function of the resin spring. FIG. 8 shows a cross section of the first lens group unit 10 without the first lens group 11 and the lens holder 111. FIG. 8A shows a retraction state in which the rotary moving ring 18 has moved to the imaging surface side in the optical axis direction. FIG. 8B shows the extended state in which the rotary moving ring 18 has moved to the subject side in the optical axis direction.

  The resin spring 185 generates an urging force that separates or approaches each other in the optical axis direction between the rotational movement ring 18 and the barrier drive ring 15. In FIG. 8A, the ball R186 at the tip of the resin spring 185 is separated from the contact portion 153 of the barrier drive ring 15 and does not act on each other. On the other hand, as shown in FIG. 8B, in the extended state of the rotary moving ring 18, the ball R186 and the contact portion 153 come into contact with each other, and the rotary moving ring 18 moves toward the imaging surface side by the elastic force of the resin spring 185. Be energized. That is, the resin spring 185 functions as second urging means. The resin spring 185 transmits the urging force of the opening spring 16 to the rotary moving ring 18 via the barrier drive ring 15, so that the rotary moving ring 18 responds to the cam engagement with the first lens group holder 14. Thus, the rotary moving ring 18 is urged in the optical axis direction. As a result, even if there is play due to play necessary for smooth cam engagement between the cam pin 181 and the cam 143, the rotary moving ring 18 is always biased to the imaging surface side, so that the feeding position is reproduced. Accuracy is improved.

  Further, as shown in FIG. 7, the cross-sectional shape of the cam 143 (145, 146) is not perpendicular to the optical axis but has a predetermined inclination. That is, the contact surface for cam engagement between the rotary moving ring 18 and the first lens group holder is not orthogonal to the optical axis. As a result, the rotational moving ring 18 generates a component force in the direction along the inclination, that is, toward the optical axis, by the biasing force toward the imaging surface. There are three cams 143, and each cam generates a component force toward the optical axis. For this reason, the rotational movement ring 18 has a centering action around the optical axis, and the positional accuracy and the tilting accuracy of the rotational movement ring 18 in the plane orthogonal to the optical axis are improved.

  The resin spring 185 does not act on the rotational moving ring 18 in the retracted state in which the rotational moving ring 18 is retracted toward the imaging surface, but acts in the extended state. The rotational force when the rotary moving ring 18 is extended is due to the spring force of the opening spring 16 through the barrier drive ring 15. For this reason, the elastic force of the resin spring 185 and the spring force of the opening spring 16 act in opposite directions. Therefore, the spring force of the opening spring 16 must be increased according to the elastic force of the resin spring 185. However, as in the lens barrel of this embodiment, by configuring the resin spring 185 to act only in the extended state, the strength of the spring force of the opening spring 16 can be increased when the resin spring 185 always acts. It can be weakened. As a result, since it is not necessary to make the spring hooking portion of the opening spring 16 thick, it is advantageous for downsizing, and it is not necessary to pull a strong spring during assembly, so that workability is improved.

  The resin spring 185 needs to always exhibit its elastic force without being plastically deformed. Therefore, the lens holder 111 is provided with a wall 114 (FIGS. 4 and 7) to limit the exposure of the resin spring 185. Thereby, for example, the possibility that a disturbance is applied from the outside through the opening 121 to impair the function of the resin spring 185 is reduced. In addition, a hole extending in the direction of the optical axis necessary for molding may be formed in the resin spring 185 portion. However, the wall 114 can reduce entry of dust and light from the hole.

  The resin spring 185 only needs to exhibit a desired elastic force, and is not necessarily made of resin. Even if the barrier drive ring 15 is provided with the resin spring 185 and the rotary moving ring 18 is provided with the contact portion, there is no difference in the effect of improving the positional accuracy of the barrier drive ring 15.

  As described above, according to the lens barrel of the present embodiment, the feeding position reproduction accuracy of the first lens group 11 can be improved by the action of the resin spring 185, so that the position sensitivity and the eccentricity sensitivity are improved. It can be applied to an optical system having high sensitivity to falling. In addition, since the lens eccentricity adjusting mechanism and the tilt adjusting mechanism are built in, the present invention can be applied to an optical system having a high degree of sensitivity that requires adjustment.

DESCRIPTION OF SYMBOLS 10 1st lens group unit 11 1st lens group 13 Barrier blade | wing 14 1st lens group holder 15 Barrier drive ring 18 Rotation movable ring

Claims (8)

A holding member for holding the lens;
A member that shields the lens, the shielding member that transitions between a shielding state that shields the lens and an exposed opening state;
A driving member that drives the shielding member to transition to the shielding state or the open state;
First biasing means for biasing the driving member so that the shielding member is in an open state;
A lens holding unit that holds the holding member movably in the optical axis direction by cam engagement and holds the driving member and the first urging means;
When the urging force of the first urging means is transmitted to the holding member via the drive member, the holding member is displaced in the optical axis direction in accordance with the cam engagement with the lens holding unit. A second urging means for urging the holding member in the optical axis direction ,
The second urging means generates a urging force for separating or approaching each other in the optical axis direction between the holding member and the driving member . The lens barrel according to claim 1, wherein the second urging unit urges the holding member toward the imaging surface side while the holding member is displaced toward the subject side. A cam pin provided on the outer surface of the holding member is cam-engaged with a cam provided on the inner surface of the lens holding unit,
The cam provided on the inner surface of the holding member connects the first cam, the second cam provided closer to the subject than the first cam, and the first cam and the second cam. Have a third cam,
The lens barrel according to claim 1 or 2, wherein the cam pin engages with the second cam when the shielding member is in the open state. The lens barrel according to any one of claims 1 to 3, wherein a contact surface of the cam engagement between the holding member and the lens holding unit is not orthogonal to the optical axis. The biasing force of said second biasing means, the lens according to any one of claims 1 to 4 wherein the holding member is characterized in that it does not act on the retaining member is in the state of convolutionally on the imaging surface side A lens barrel. The lens barrel according to any one of claims 1 to 5 , wherein the second urging means is provided on at least one of the holding member or the driving member. The lens barrel according to any one of claims 1 to 6 , wherein the holding member has an adhesive application portion for holding the lens in an eccentric state or in a tilted state. An imaging apparatus comprising the lens barrel according to any one of claims 1 to 7 .

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