JP2018146811A - Lens barrel and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a lens barrel whose diameter is reduced; and a compact imaging apparatus including the lens barrel.SOLUTION: A lens barrel includes: a zoom rotation delivering ring 7 that is rotated when a zoom operation ring 4 is operated during zooming; and a zoom cam ring 12 and a focus cam ring 13 that are arranged on an inner diameter side of the zoom rotation delivering ring 7 and that are driven by the zoom rotation delivering ring 7 to respectively move lens groups 32-35 in an optical axis direction. The zoom cam ring 12 and the focus cam ring 13 are arranged to line in the optical axis direction at an identical radial position. The zoom cam ring 12 and the focus cam ring 13 do not overlap with each other in a radial direction, and therefore, the diameter of a lens barrel LX can be reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens barrel and an imaging apparatus using the lens barrel.

  The inner focus zoom lens is configured to move the entire zoom range when a plurality of lens groups (hereinafter referred to as a lens group including a lens in which one or a plurality of lenses are integrated) is moved in the optical axis direction during zooming. There is a problem that the focal point shift occurs. As countermeasures, a focus cam ring for moving a lens group that performs focus adjustment (hereinafter, this lens group may be referred to as a focus lens group), and a cam follower of a focus lens group that fits in the cam groove, A mechanism has been proposed in which the fitting position is changed with zooming.

  In Patent Document 1, a focus cam cylinder is disposed on the inner diameter side of a first cam cylinder that moves a plurality of lens groups during zooming, and the focus lens group is cam-fitted to the focus cam cylinder. By rotating the first cam cylinder around the optical axis, the plurality of lens groups are moved in the optical axis direction to perform zooming, and the focus cam cylinder is rotated around the optical axis in conjunction with the rotation of the first cam cylinder. Thus, the fitting position between the focus cam cylinder and the focus lens group is changed. Thereby, focus adjustment is performed by the focus lens group.

JP 2008-203333 A

  In the technique of Patent Document 1, since the focus cam cylinder is arranged on the inner diameter side of the first cam cylinder, the focus cam cylinder and the first cam cylinder overlap each other in the radial direction (radial direction). The outer diameter of the lens barrel increases, and it is difficult to reduce the diameter of the lens barrel. Furthermore, it is difficult to reduce the size of an imaging apparatus using the lens barrel.

  In addition, the lens barrel may employ a configuration in which the focus lens group is driven by a motor. However, when the motor is disposed on a fixed cylinder in the lens barrel, the focus lens group moves the motor in the optical axis direction. There is also a problem that it is difficult to reduce the diameter of the lens barrel because the drive mechanism for connecting the lenses becomes large.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens barrel that has a reduced diameter and a small imaging device that includes the lens barrel.

  The lens barrel of the present invention is disposed on the inner diameter side of the zoom rotation extension ring that is driven during zooming, and is moved by the zoom rotation extension ring to move the respective lens groups in the optical axis direction. The zoom cam ring and the focus cam ring are provided, and the zoom cam ring and the focus cam ring are arranged side by side in the optical axis direction at the same radial position.

  According to the present invention, a small-diameter lens barrel can be realized. Further, according to the present invention, a small imaging device can be realized.

FIG. 3 is a longitudinal sectional view along the optical axis in the short focus state of the lens barrel of the first embodiment. FIG. 3 is a longitudinal sectional view along the optical axis of the lens barrel of Embodiment 1 in a long focal state. FIG. 3 is an exploded perspective view schematically showing each part of the main part of the first embodiment. The external appearance perspective view and expansion | deployment figure of a 3rd stationary ring. The external appearance perspective view and expansion | deployment figure of a zoom rotation payout ring. FIG. 3 is a development view of a second zoom cam ring. The external perspective view and expansion | deployment figure of a rectilinear advance ring. The external appearance perspective view and expansion | deployment figure of a 1st zoom cam ring. FIG. 3 is an external perspective view and a development view of a focus cam ring. FIG. 3 is an external perspective view of a focus cam follower holding ring and a focus rotation ring, and a development view of the focus cam follower holding ring. FIG. 3 is an external perspective view of a second group moving ring. The enlarged view of the cam groove 76. FIG. FIG. 6 is a longitudinal sectional view along the optical axis in a short focus state of the lens barrel of Embodiment 2. FIG. 6 is a longitudinal sectional view along the optical axis in the long focal state of the lens barrel of the second embodiment. FIG. 6 is an exploded perspective view schematically showing a part of main parts of Embodiment 2. FIG. 6 is a development view of a focus cam ring according to a second embodiment.

(Embodiment 1)
Next, an embodiment of the present invention will be described. 1 and 2 are cross-sectional views along the optical axis Ax of the lens barrel LX according to the first embodiment of the present invention, and show a long focus (tele) state and a short focus (wide) state, respectively. 1 and 2 are cross-sectional views at different angular positions. The lens barrel LX is configured as a zoom interchangeable lens of a single-lens reflex camera. By rotating the zoom operation ring 4 around the optical axis of the lens barrel, the long focal point (tele) side and the short focal point (wide) are arranged. Zoom to the side. In the following, the rotation is to rotate around the optical axis. Further, the subsequent movement is movement in the optical axis direction. Focusing (focusing) is automatically performed by a built-in motor, but manual focusing by rotating the focus operation ring 5 is also possible.

  FIG. 3 is an exploded view schematically showing the main parts of the lens barrel LX as viewed from the direction of the subject. 4 to 11 show the main parts. In FIGS. 4, 5 and 7 to 10, (a) is an external perspective view seen from the image plane side, and (b) is a developed view. FIG. 11 is an external perspective view.

  1 to 11, the lens barrel LX has a first lens group 31, a second lens group 32, a third lens group 33, and a fourth lens group 34 from the subject side to the elephant side. The zoom lens barrel is arranged in the order of the fifth lens group 35. These first to fifth lens groups 31 to 35 are each composed of a single lens or a group lens composed of a plurality of single lenses, but in FIGS. 1 and 2, as a single lens, for simplification. It is described. In this embodiment, among these lens groups 31 to 35, the second lens group 32 is configured as a focus lens group for performing focusing.

  In the lens barrel LX, the first fixed ring 2, the second fixed ring 3, and the third fixed ring 6 are concentrically arranged from the outer diameter side and are integrally connected to each other. The first fixed ring 2 is also called a mount holding ring, and a mount 1 for mounting on a camera body (not shown) is fixed. The second fixed ring 3 includes a first support ring 3A on the rear side and a second support ring 3B on the front side, which are also integrally connected. The third fixed ring 6 is as shown in FIG. 4 and is provided with a second cam groove 63 and a second rectilinear groove 67.

  On the outer diameter side of the second support ring 3B, a zoom operation ring 4 is disposed in a state of being restricted in movement in the optical axis direction by the second support ring 3B, and is rotated by a photographer's manual operation during zooming. It has come to be. By the rotation of the zoom operation ring 4, the focal length of the lens barrel LX is changed from tele to wide.

  On the outer diameter side of the third fixed ring 6, a zoom rotation feeding ring 7, a second zoom cam ring 8, a first group moving ring 9, and a zoom outer cylinder 10 are arranged in order from the inner diameter side to the outer diameter side. Yes. Among these, the second zoom cam ring 8 and the zoom outer cylinder 10 are connected, and both are rotated and moved integrally.

  The zoom outer cylinder 10 is provided with a first follower 40 that fits into the rectilinear groove 51 of the zoom operation ring 4. The zoom outer cylinder 10 and the second zoom cam ring 8 are rotated by the zoom operation ring 4. It is rotated integrally with the rotation. A third follower 42 that fits into the first rectilinear groove 62 of the second zoom cam ring 8 is attached to the zoom rotation extension ring 7, and the zoom rotation extension ring 7 is accompanied by the rotation of the second zoom cam ring 8. Are rotated together. As shown in FIG. 5, the zoom rotation feeding ring 7 is provided with a first coupling hole 64 and a third cam groove 65. Further, as shown in FIG. 6, the second zoom cam ring 8 is provided with a first cam groove 61 in addition to the first rectilinear groove 62.

  A rectilinear ring 11 that is movable in the optical axis direction is disposed on the inner diameter side of the third fixed ring 6. As shown in FIG. 7, the rectilinear ring 11 is provided with a cam groove 66 and a fifth rectilinear groove 74, and further with a second fitting hole 68 and third and fourth rectilinear grooves 70 and 72. . Further, the first zoom cam ring 12 and the focus cam ring 13 are arranged at the same radial position on the inner diameter side of the linear movement ring 11. The first zoom cam ring 12 is disposed on the image plane side in the optical axis direction, and the focus cam ring 13 is disposed on the subject side in the optical axis direction.

  A rectilinear guide ring 22 is coupled to the subject side of the rectilinear ring 11. The linear zoom ring 11 and the linear guide ring 22 sandwich the second zoom cam ring 8 in the optical axis direction. The rectilinear ring 11 and the rectilinear guide ring 22 are integrated in the optical axis direction, and the second zoom cam ring 8 is rotatable with respect to the rectilinear ring 11 and the rectilinear guide ring 22. Since the rectilinear guide ring 22 has a convex portion 81 on the outer diameter side, and this convex portion 81 is fitted in a rectilinear groove 82 provided on the inner diameter side of the first group moving ring 9, the first group moving ring 9 does not rotate.

  A first group lens frame 23 that supports the first lens group 31 is attached to the first group moving ring 9. The first follower 41 that fits into the first cam groove 61 of the second zoom cam ring 8 is attached to the first group moving ring 9. Accordingly, the first group moving ring 9 is moved in the optical axis direction without rotating by the rotation of the second zoom cam ring 8, and the first lens group 31 is moved in the optical axis direction.

  The first zoom cam ring 12 is provided with a fourth follower 43 fitted in the first coupling hole 64 of the zoom rotation feeding ring 7, and the first zoom cam ring 12 and the zoom rotation feeding ring 7 have a rotation direction and Integrated in the optical axis direction. In addition, due to the fitting of the third follower 42 and the second cam groove 63 of the stationary ring 6, the first zoom cam ring 12 and the zoom rotation feeding ring 7 rotate integrally with the rotation of the second zoom cam ring 8 and the light. It is moved in the axial direction. As shown in FIG. 8, the first zoom cam ring 12 is provided with a fourth cam groove 69, a fifth cam groove 71, and a sixth cam groove 73.

  On the inner diameter side of the first zoom cam ring 12, a third group moving ring 25, a fourth group moving ring 27, and a fifth group moving ring 29 are arranged. A third group lens frame 26 that supports the third lens group 33 is attached to the third group moving ring 25. Further, the third group moving ring 25 has a sixth follower that fits into the second rectilinear groove 67 of the fixed ring 6, the second fitting hole 68 of the rectilinear ring 11, and the fourth cam groove 69 of the first zoom cam ring 12. 45 is attached.

  A fourth group lens frame 28 that supports the fourth lens group 34 is attached to the fourth group moving ring 27. The fourth group moving ring 27 is attached with a seventh follower 46 that fits into the third rectilinear groove 70 of the rectilinear ring 11 and the fifth cam groove 71 of the first zoom cam ring 12.

  A fifth group lens frame 30 that supports the fifth lens group 35 is attached to the fifth group moving ring 29. The fifth group moving ring 29 is provided with an eighth follower 47 that fits into the fourth rectilinear groove 72 of the rectilinear ring 11 and the sixth cam groove 73 of the first zoom cam ring 12.

  With this configuration, when the first zoom cam ring 12 rotates, the third group moving ring 25, the fourth group moving ring 27, and the fifth group moving ring 28 are moved in the optical axis direction, respectively, and the third lens group 33 and the fourth lens group 34 are moved. And the fifth lens group 35 is moved in the optical axis direction.

  The focus cam ring 13 is provided with a fifth follower 44 that fits into the third cam groove 65 of the zoom rotation feeding ring 7 and the cam groove 66 of the linear movement ring 11. The focus cam ring 13 is moved in the optical axis direction with the rotation of the zoom rotation feeding ring 7 and is rotated with the movement of the rectilinear ring 11 in the optical axis direction. The focus cam ring 13 is provided with a cam groove 75 as shown in FIG.

  On the inner diameter side of the focus cam ring 13, a focus cam follower holding ring 14 and a focus rotation ring 15 are disposed at the same diameter position. The focus cam follower holding ring 14 and the focus rotation ring 15 are integrally coupled. A tenth follower 49 that fits into the cam groove 75 of the focus cam ring 13 is attached to the focus cam follower holding ring 14. The focus cam follower holding ring 14 is provided with a cam groove 76 as shown in FIG.

  A second group moving ring 16 is disposed on the inner diameter side of the focus cam follower holding ring 14 and the focus rotation ring 15. As shown in FIG. 11, the two-group moving ring 16 has an inner diameter side of the rectilinear ring 11, and the diameter of the second group moving ring 16 becomes narrower as it goes from there to the image plane side. Is arranged. A second group lens frame 24 that supports the second lens group 32 is attached to the second group moving ring 16.

  Further, the second follower moving ring 16 is provided with a ninth follower 48 that fits in the fifth rectilinear groove 74 of the rectilinear ring 11 and an eleventh follower 50 that fits in the cam groove 76 of the focus cam follower holding ring 14. It has been. Accordingly, the focus cam follower holding ring 14 and the focus rotation ring 15 are moved in the optical axis direction along with the rotation of the focus cam ring 13, and the second group moving ring 16 and the second group lens L2 are simultaneously moved in the optical axis direction. .

  The second group moving ring 16 includes a motor as an actuator, here a DC drive type motor, and a gear for transmitting the rotational force of the motor to the focus rotating ring 15 to rotate the focus rotating ring 15. Row 20 is mounted. The gear train 20 is configured as, for example, a reduction gear mechanism, and the final gear 84 of the reduction gear mechanism is engaged with the arc gear 83 of the focus rotation ring 15.

  A scale holding ring 17 is disposed at a position across the inner diameter side of the first zoom cam ring 12 and the focus cam follower holding ring 14 on the outer diameter side of the second group moving ring 6. The scale holding ring 17 is not coupled to the first zoom cam ring 12 in the rotational direction. Although not shown in the drawing, the scale holding ring 17 has a rectilinear groove on the inner diameter side, is fitted with a convex portion provided on the second group moving ring 16, and does not rotate with the first zoom cam ring 12, but the optical axis. Move in the direction.

  A scale 18 is attached to the inner diameter surface of the scale holding ring 17. A first displacement sensor 19 is attached to the outer diameter surface of the second group moving ring 16 facing the inner diameter surface via a suspension plate 52 and a sensor holder 53. The first displacement sensor 19 detects the amount of movement of the scale 18, that is, the amount of movement of the second group moving ring 16 relative to the scale holding ring 17 in the optical axis direction.

  As shown in FIG. 2, a focus resistance plate 54 is attached to the second group moving ring 16, and a focus brush 55 is attached to the focus rotation ring 15, thereby constituting a rotation angle sensor. In this rotation angle sensor, when the focus rotation ring 15 rotates, the angular position where the focus brush 55 and the focus resistance plate 54 come into contact changes, and the resistance value between the terminals of the focus resistance plate 54 changes. Thereby, the amount of movement of the focus rotation ring 15 in the rotational direction, that is, the angular position is detected as a change in resistance value. Therefore, the rotation angle of the focus cam follower holding ring 14 connected to the focus rotation ring 15 is detected.

  The focus operation ring 5 is disposed between the first fixed ring 2 and the second fixed ring 3 so as to be restricted in movement in the optical axis direction, and is rotated by a photographer's manual operation. The focus operation ring 5 has a ring gear 38 on the inner diameter side, and meshes with a detection gear 36 that is pivotally supported by the second fixed ring 3. The detection gear 36 is rotated as the focus operation ring 5 is rotated. A pulser 37 that rotates integrally is fixed to the shaft portion of the detection gear 36, and a second displacement sensor 39 that detects the rotation angle of the pulser 37 is disposed on the second fixed ring 3. Here, the second displacement sensor 39 includes a pulsar disk and a photo interrupter that detects the rotation angle of the pulsar disk.

  Although not shown here, another second displacement sensor is provided at a position where the detection phase is different from that of the second sensor 39, that is, a position where the circumferential direction is different. By detecting the displacement sensor 39, the rotation amount, rotation speed, and rotation direction of the focus operation ring 5 can be detected.

  The zoom operation, manual focus operation, and autofocus operation in the lens barrel LX having the above configuration will be described.

(Zoom operation)
During zooming, when the photographer rotates the zoom operation ring 4, the zoom outer cylinder 10 is integrally rotated by the fitting of the straight movement groove 51 of the zoom operation ring 4 and the first follower 40, and coupled thereto. The second zoom cam ring 8 is also rotated integrally. Further, by fitting the first rectilinear groove 62 of the second zoom cam ring 8 and the third follower 42, the zoom rotation extension ring 7 is rotated integrally with the rotation of the second zoom cam ring 8, and the zoom rotation extension ring 7. Due to the fitting of the first coupling hole 64 and the fourth follower 43, the first zoom cam ring 12 also rotates at the same rotation angle as the zoom operation ring 4. At this time, the zoom rotation feeding ring 7 and the first zoom cam ring 12 are moved in the optical axis direction simultaneously with the rotation by the cam action of the third fixed ring 6.

  When the first zoom cam ring 12 rotates, the rectilinear ring 11 moves in the optical axis direction by the cam action of the sixth follower 45, the second rectilinear groove 67 and the fourth cam groove 69, and the rectilinear guide ring 22 integral therewith is integrated. The second zoom cam ring 8 also moves in the optical axis direction integrally therewith. At the same time, the third group moving ring 26 moves without rotating in the optical axis direction, and the third group lens frame 26 and the third lens group 33 supported by the third group moving ring 26 move in the optical axis direction.

  When the first zoom cam ring 12 rotates, the fourth group moving ring 27 moves without being rotated in the optical axis direction by the cam action of the seventh follower 46, the third rectilinear groove 70 and the fifth cam groove 71, and is supported by this. The fourth group lens frame 28 and the fourth lens group 34 move in the optical axis direction.

  When the first zoom cam ring 12 rotates, the fifth group moving ring 29 moves without rotating in the optical axis direction and is supported by the cam action of the eighth follower 47, the fourth rectilinear groove 72, and the sixth cam groove 73. The fifth group lens frame 30 and the fifth lens group 35 move in the optical axis direction.

  When the first zoom cam ring 12 rotates, the rectilinear ring 11 moves in the optical axis direction by fitting the sixth cam follower 45 and the second fitting hole 68 of the rectilinear ring 11. Due to the movement of the rectilinear ring 11, the rectilinear guide ring 22 integrated therewith also moves integrally. Therefore, the second zoom cam ring 8 sandwiched in the optical axis direction by the rectilinear ring 11 and the rectilinear guide ring 22 moves in the optical axis direction together with the rectilinear ring 11 and the rectilinear guide ring 22. That is, it rotates as described above while moving.

  When the second zoom cam ring 8 moves and rotates in the optical axis direction, the first group moving ring 9 moves in the optical axis direction by the cam action of the first cam groove 61 and the second follower 41 of the second zum cam ring 8, The first lens group frame 23 and the first lens group 31 supported thereby move in the optical axis direction.

  As described above, the zoom rotation extension ring 7 is moved in the optical axis direction while rotating by the second zoom cam ring 8, and accordingly, the rectilinear ring 11 is also moved in the optical axis direction. Is different. By the rotation of the zoom rotation feeding ring 7 and the movement of the rectilinear ring 11, the focus cam ring 13 is driven by the cam action of the fifth follower 44 and the third cam groove 65 and the cam action of the fifth follower 44 and the cam groove 66. The zoom operation ring 4 rotates at an angle different from the rotation angle and moves in the optical axis direction.

  When the focus cam ring 13 moves in the optical axis direction while rotating, the focus cam follower holding ring 14 is moved in the optical axis direction by the cam action of the tenth follower 49 and the cam groove 75, and the focus rotation ring coupled thereto. 15 is moved in the optical axis direction. At the same time, the second group moving ring 16 and the second lens group 32 move in the optical axis direction by fitting the eleventh follower 50 of the second group moving ring 16 and the cam groove 76 of the focus cam follower holding ring 14. Further, by fitting the ninth cam follower 48 of the second group moving ring 16 and the fifth straight groove 74 of the straight moving ring 11, the second group moving ring 16 moves in the optical axis direction without rotating.

  When the focus cam ring 13 rotates, the focus cam follower holding ring 14 does not rotate by meshing with the gear train 20 connected to the actuator 21, so that the fitting angle position of the tenth follower 49 and the cam groove 75 changes. To do. Since the focus cam follower holding ring 14 does not rotate, the fitting position between the eleventh follower 50 and the cam groove 76 does not change, and the second group moving ring 16 is held integrally with the focus cam follower holding ring 14 in the optical axis direction. The As a result, the second group moving ring 16 is moved relative to the focus cam ring 13 in the optical axis direction within the length range of the fifth rectilinear groove 74 in the optical axis direction due to the rotation of the focus cam ring 13, and the second group moving ring 16 is moved in the second direction during zoom operation. Defocus is corrected when the lens group 32 is moved, and the in-focus state is maintained.

  In summary, in this lens barrel LX, when the zoom operation ring 4 is rotated, the zoom rotation feeding ring 7 rotates while moving, and the first zoom cam ring 12 and the focus cam ring 13 also move by this movement and rotation. Rotate while. The third lens group 33, the fourth lens group 34, and the fifth lens group 35 are moved by the movement and rotation of the first zoom cam ring 12. At the same time, the second zoom cam ring 8 is rotated while moving to move the first group moving ring 9. The first lens group 31 is moved through. At the same time, when the zoom rotation feeding ring 7 moves, the fifth follower 44 moves and the second lens group 32 moves. Thereby, a zoom operation is performed. Further, the second lens group 32 is moved by the movement and rotation of the first focus cam ring 13, and the focusing operation is performed.

  That is, the first zoom cam ring 12 and the focus cam ring 13 are configured to be moved and rotated by the zoom rotation feeding ring 7. The first zoom cam ring 12 and the focus cam ring 13 correspond to the first cam cylinder and the focus cam cylinder in Patent Document 1, respectively. In Patent Document 1, this focus cam cylinder is defined as the inner diameter of the first cam cylinder. Therefore, the outer diameter of the lens barrel is large.

  In the first embodiment, the first zoom cam ring 12 and the focus cam ring 13 are disposed at the same radial position on the inner diameter side of the zoom rotation feeding ring 7, and the first zoom cam ring 12 and the focus cam ring 13 are arranged in the radial direction. Do not overlap. Specifically, a rectilinear ring 11 is arranged on the inner diameter side of the zoom rotation feeding ring 7, and the focus cam ring 13 and the first zoom cam ring 12 are aligned in the optical axis direction at the same radial position on the inner diameter side of the rectilinear ring 11. Is arranged. Therefore, the lens barrel can be designed to have a small diameter corresponding to at least the dimension corresponding to the thickness of the focus cam ring 13 in the radial direction, and the lens barrel can be reduced in diameter.

(Manual focus operation)
In the manual focus, when the photographer rotates the focus operation ring 5, the pulsar 37 is rotated by the rotation of the MF gear 36 meshed with the focus operation ring 5, and the amount of rotation of the focus operation ring 5 is detected. At this time, the rotation speed and direction of the focus operation ring 5 are detected by detection with two second displacement sensors (not shown).

  When the motor 21 is driven based on the rotation of the focus operation ring 5, that is, based on the rotation amount, rotation speed, and rotation direction detected by the second displacement sensor 39, the rotation from the final gear 84 of the gear train 20 to the arc gear 83 is performed. The focus rotation ring 15 and the focus cam follower holding ring 14 coupled thereto rotate. At this time, the focus cam ring 13 does not rotate or move.

  When the focus cam follower holding ring 14 rotates relative to the focus cam ring 13, the focus cam follower holding ring 14 is rotated by the cam action of the tenth follower 49 and the cam groove 75 of the focus cam ring 13 while rotating in the optical axis direction. Move to. When the focus cam follower holding ring 14 is rotated, the ninth follower 48 of the second group moving ring 16 is fitted into the fifth rectilinear groove 74 and does not rotate, so that the eleventh follower 50 and the cam groove 76 of the second group moving ring 16 are not rotated. Due to the cam action, the second group moving ring 16 moves along the cam groove 76 in the optical axis direction.

  When the second group moving ring 16 moves in the optical axis direction, the first displacement sensor 19, the suspension plate 52, and the sensor holder 53 also move in the optical axis direction, but the scale 18 of the scale holding ring 17 together with the second group moving ring 16 Since the first displacement sensor 19 detects the relative movement amount of the scale 18 and the first displacement sensor 19, the movement amount of the scale 18, that is, the movement amount of the second lens group 32 is detected.

  Based on the movement amount of the second group moving ring 16 detected by the first displacement sensor 19 and the rotation amount, rotation speed, and rotation direction of the focus operation ring 5 detected by the second displacement sensor 39, feedback control of the motor 21 is performed. By doing so, the second group moving ring 16 is controlled to a position in the optical axis direction corresponding to the operation of the focus operation ring 5, and the manual focus is executed. At this time, the rotation angle of the focus cam follower holding ring 14 detected by the rotation angle sensor instead of the first displacement sensor 19 or together with the first displacement sensor 19 may be used.

(Auto focus operation)
Autofocus communicates a signal corresponding to the subject distance measured by the camera body to the lens barrel LX, and the lens barrel LX controls the rotation of the motor 21 in a predetermined amount, a predetermined speed, and a predetermined direction based on the signal. Also at this time, by rotating the motor 21 by feedback control based on the detection of the first displacement sensor 19, the second lens group 32 is moved in the optical axis direction, and autofocus is executed. For example, in a camera (imaging device) that employs a contrast AF (autofocus) method, the contrast is calculated by the image sensor while moving the second lens group 32, and this contrast is detected by the detection amount of the first displacement sensor 19. The position of the second lens group 32 in the optical axis direction is controlled so that the pegging and the contrast reach a peak.

  Here, the cam groove 76 of the focus cam follower holding ring 14 has no inclination in the use range from the near point to the infinity point, as shown in an enlarged view in FIG. 12, and from the infinity point to the infinity side end point. Is a shape with an inclination. As a result, the second group moving ring 16 moves in the optical axis direction from the short distance to infinity without rotating by the same amount as the focus cam follower holding ring 14, and the cam groove 76 has an inclination beyond the infinity. Then, the focus cam follower holding ring 14 moves by an amount obtained by adding the cam shape of the cam groove 76 to the movement amount of the focus cam follower holding ring 14. That is, it is possible to secure the driving range of the second lens group 32 that extends to all focal lengths from short distance to infinity and further to the infinity side end point that exceeds this infinity.

  Therefore, in the camera adopting the contrast AF method described above, the contrast peak is redundant particularly on the wide side of the lens barrel LX, but also on the wide side from the near distance to infinity. The second lens group 32 can be driven in a range extending from far to the end point on the infinity side, and a suitable contrast AF can be realized.

  In both the manual focus operation and the autofocus operation described above, the focus cam follower holding ring 14 is rotationally driven by the motor 21 mounted on the second group moving ring 16. Therefore, since the focus cam follower holding ring 14 and the motor 21 can be connected by the small motor case 20, the motor 21 is mounted on the fixed portion of the lens barrel, and the motor 21 and the focus cam follower holding ring 14 are connected by a connecting arm or the like. Compared to the configuration in which the lens arms are connected, it is not necessary to secure a region for disposing the connecting arm or the like, and the lens barrel can be configured in a small size.

  Further, since the motor 21 is mounted on the two-group moving ring 16 of the second lens group 32 in the middle of the five lens groups 31 to 35 arranged in the optical axis direction, the optical axis of the lens barrel LX. The motor 21 is arranged at a position closer to the center of the direction, the weight balance in the optical axis direction can be easily achieved, and the handling and operability of the lens barrel are improved.

(Embodiment 2)
13 and 14 are longitudinal sectional views of Embodiment 2 of the present invention. The second embodiment is mainly different from the first embodiment in the configuration of the focus cam ring 13, the focus cam follower holding ring 14, the focus rotation ring 15, and the second group moving ring 16. In FIG. 13, the parts related to the different configuration are hatched, and these configurations will be described below.

  FIG. 15 is a schematic exploded perspective view of the main part, and FIG. 16 is a development view of the focus cam ring 13. The focus cam ring 13 is provided with a cam groove 75 and a cam groove 76. The cam groove 76 is provided in the focus cam follower holding ring 14 in the embodiment. A focus rotation ring 15 is disposed at the same radial position on the subject side of the focus cam ring 13 and is coupled to the focus cam ring 13. The final gear 83 of the gear case 20 driven by the motor 21 is engaged with the arc gear 84 of the focus rotation ring 15.

  A focus cam follower holding ring 14 is disposed on the inner diameter side of the focus cam ring 13. A fifth follower 44 is attached to the focus cam follower holding ring 14, and is fitted into the cam groove 75 of the focus cam ring 13, the cam groove 66 of the rectilinear ring 11, and the cam groove 65 of the zoom rotation feeding ring 7. ing. In the first embodiment, the cam groove 76 is provided in the focus cam follower holding ring 14. However, since the cam groove 76 is provided in the focus cam ring 13 as described above, it is not provided in the second embodiment. .

  An eleventh follower 50 is attached to the second group moving ring 16 and is fitted in the cam groove 76 of the focus cam ring 13 and the straight movement groove 74 of the straight movement ring 11. Further, a rotation angle sensor is configured between the second group moving ring 16 and the focus rotation ring 15 as in the first embodiment, and the focus cam ring 13 connected to the focus rotation ring 15 by this rotation angle sensor. Detect the rotation angle.

(Zoom operation)
Since the zoom operation is basically the same as that of the first embodiment, the operation of the second group moving ring 16 different from that of the first embodiment will be described. The rotation of the second zoom cam ring 8 accompanying the rotation operation of the zoom operation ring 4 causes the zoom rotation extension ring 7 to move in the direction of the optical axis while rotating, and accordingly, the linear movement ring 11 also moves in the direction of the optical axis. The amount of movement differs depending on the shape. Due to the rotation of the zoom rotation feeding ring 7 and the movement of the rectilinear ring 11 in the optical axis direction, the focus cam follower holding ring 14 causes the cam action of the fifth follower 44 and the third cam groove 65, and the fifth follower 44 and the cam groove 66. It moves in the optical axis direction while rotating by the cam action.

  When the focus cam follower holding ring 14 moves in the optical axis direction while rotating, the focus cam follower holding ring 14 is moved by fitting the eleventh follower 50 of the second group moving ring 16 and the cam groove 76 of the focus cam ring 13. Moves in the direction of the optical axis. At this time, the focus cam ring 13 is moved relative to the focus cam follower holding ring 14 by the movement of the fifth follower 44 of the focus cam follower holding ring 14 and the cam groove 75 of the focus cam ring 13. Rotates while changing position.

  As a result, the second group moving ring 16 is moved relative to the focus cam ring 13 in the optical axis direction within the length range of the fifth rectilinear groove 74 in the optical axis direction, and the second lens group 32 is moved in the optical axis direction during zoom operation. The defocus when the lens moves to is corrected and the in-focus state is maintained.

  Also in the second embodiment, the first zoom cam ring 12 and the focus cam ring 13 are arranged on the inner diameter side of the zoom rotation feeding ring 7, specifically, the inner diameter of the rectilinear ring 11 disposed on the inner diameter side of the zoom rotation feeding ring 7. A focus cam ring 13 and a first zoom cam ring 12 are arranged in the same radial position on the side in the optical axis direction. As a result, the lens barrel can be designed to have a small diameter, and the diameter of the lens barrel can be reduced.

(Manual focus operation)
When the motor 21 is driven based on the rotation of the focus operation ring 5, that is, the rotation amount, rotation speed, and rotation direction detected by the second displacement sensor 39, the rotation is transmitted to the ring gear 20 through the gear case and the focus rotation ring 15. The focus cam ring 13 coupled thereto rotates. At this time, the focus cam follower holding ring 14 does not rotate and move in the optical axis direction.

  When the focus cam ring 13 rotates relative to the focus cam follower holding ring 14, the cam action between the eleventh follower 50 and the cam groove 76 of the focus cam ring 13 further causes the fifth cam follower 44 and the cam groove 75 to The cam action is applied, and the second group moving ring 16 moves along the cam groove 76 in the optical axis direction. When the second group moving ring 16 moves in the optical axis direction, the movement amount of the second group moving ring 16 detected by the first displacement sensor 19 and the rotation amount and rotation of the focus operation ring 5 detected by the second displacement sensor 39 By performing feedback control of the motor 21 based on the speed and rotation direction, the second group moving ring 16 is controlled to a position in the optical axis direction corresponding to the operation of the focus operation ring 5, and manual focusing is performed. It is the same as Form 1. At this time, the rotation angle of the focus cam ring 13 detected by the rotation angle sensor instead of the first displacement sensor 19 or together with the first displacement sensor 19 may be used.

(Auto focus operation)
The autofocus is also the same as in the first embodiment, and a signal corresponding to the subject distance measured by the camera body is communicated to the lens barrel LX, and the lens barrel LX performs a predetermined amount, a predetermined speed, and a predetermined direction based on the signal. The rotation of the motor 21 is controlled. Also at this time, by rotating the motor 21 by feedback control based on the detection of the first displacement sensor 19, the second lens group 32 is moved in the optical axis direction, and autofocus is executed.

  Here, in the second embodiment, the cam groove 76 of the focus cam ring 13 does not have an inclination in the range from the short distance point to the infinity point as in the first embodiment described in FIG. The shape is inclined to the end point on the infinity side. The eleventh follower 50 of the second group moving ring 16 is fitted in the cam groove 76. Therefore, the second lens group 32 can be driven on the wide side of the lens barrel LX from a short distance to infinity and further to the end point on the infinity side beyond this infinity, and the contrast AF method is adopted. Contrast AF suitable for the camera can be realized.

  Since the motor 21 is mounted on the two-group moving ring 16 of the intermediate second lens group 32 of the five lens groups 31 to 35 arranged in the optical axis direction, it is the same as in the first embodiment. The motor 21 is disposed at a position closer to the center of the lens barrel LX in the optical axis direction, which makes it easier to balance the weight in the optical axis direction, thereby improving the handling and operability of the lens barrel.

  In the first and second embodiments, when it is not necessary to expand the range extending from infinity to the end point on the infinity side, the cam groove 76 may be formed as a linear groove perpendicular to the optical axis.

  The present invention is not limited to the lens barrel such as the interchangeable lens described above, but can also be applied to a lens barrel integrated with the camera body. Further, the present invention is not limited to the lens barrel of a still image shooting camera, but can be applied to a lens barrel of a moving image shooting camera and a lens barrel of a digital imaging apparatus. Furthermore, it goes without saying that the present invention includes a configuration in which the lens barrel is configured as an interchangeable lens, or as a camera or an imaging device for moving image shooting that is integrated into the apparatus main body.

1 mount 2 first fixed ring (mount holding ring)
3 Second fixed ring 3A First support ring 3B Second support ring 4 Zoom operation ring 5 Focus operation ring 6 Third fixed ring 7 Zoom rotation feed ring 8 Second zoom cam ring 9 Group 1 moving ring 10 Outer cylinder 11 Straight ring 12 First zoom cam ring 13 Focus cam ring 14 Focus cam follower holding ring 15 Focus rotation ring 16 Second group moving ring 17 Scale holding ring 18 Scale 19 First displacement sensor 20 Gear train 21 Actuator 22 Straight guide rings 23, 24, 26, 28, 30 1-5 group lens frames 25, 27, 29 3-5 group moving rings 31-35 1st-5th lens group 36 detection gear 37 pulsar 39 2nd displacement sensors 40-50 1st-11th follower 51 2nd Support ring 52 Suspension plate 53 Sensor holder 54 Focus resistance plate (rotation angle sensor)
55 Focus brush (rotation angle sensor)
61 to 75 Cam groove, straight groove, fitting hole 81 convex portion 82 straight groove 83 arc gear 84 final gear

Claims (11)

  A zoom operation ring that is operated during zooming, a zoom rotation extension ring that is disposed on the inner diameter side of the zoom operation ring, moves in the optical axis direction by the zoom operation ring, and rotates about the optical axis, and this zoom rotation extension A lens barrel comprising a zoom cam ring and a focus cam ring arranged side by side in the optical axis direction at the same radial position on the inner diameter side of the ring.   A focus cam follower holding ring cam-engaged with the focus cam ring is provided, the zoom cam ring is driven by the zoom rotation extension ring to move at least one lens group in the optical axis direction, and the focus cam ring rotates the zoom The lens barrel according to claim 1, wherein the lens barrel is driven by a payout ring and a focus lens group is engaged with the focus cam follower holding ring.   The lens barrel according to claim 2, wherein the focus cam ring is cam-engaged with the zoom rotation extension ring, and the zoom cam ring is integrated with the zoom rotation extension ring.   The focus cam follower holding ring is disposed on the inner diameter side of the focus cam ring, the focus cam follower holding ring is cam-engaged with the focus cam ring and rotated relative to the focus cam ring, and the focus lens group is The lens barrel according to claim 3, wherein the lens barrel is cam-engaged with the focus cam follower holding ring.   A focus cam follower holding ring cam-engaged with the focus cam ring, the zoom cam ring being driven by the zoom rotation feeding ring to move at least one lens group in the optical axis direction, and the focus cam follower holding ring being The lens barrel according to claim 1, wherein the lens barrel is driven by a rotation feeding ring, and a focus lens group is engaged with the focus cam ring.   6. The lens barrel according to claim 5, wherein the focus cam ring is cam-engaged with the zoom rotation extension ring, and the zoom cam ring is integrated with the zoom rotation extension ring.   The focus cam follower holding ring is disposed on the inner diameter side of the focus cam ring, the focus cam follower holding ring is cam-engaged with the focus cam ring and rotated relative to the focus cam ring, and the focus lens group is The lens barrel according to claim 6, wherein the lens barrel is cam-engaged with the focus cam ring.   The lens barrel according to claim 2, further comprising an actuator that rotationally drives the focus cam follower holding ring or the focus cam ring, and the actuator is supported by the focus lens group.   The lens barrel according to claim 8, wherein the focus lens group is a lens group that is positioned in the middle of the optical axis direction among a plurality of lens groups arranged in the optical axis direction.   A zoom operation ring that is operated during zooming, and a zoom cam ring and a focus cam ring that are arranged on the inner diameter side of the zoom operation ring and are driven by the zoom operation ring to move the lens group in the optical axis direction, respectively. The lens barrel characterized in that the zoom cam ring and the focus cam ring are arranged side by side in the optical axis direction at the same radial position. An imaging device comprising the lens barrel according to claim 1.

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