Lens barrel and imaging apparatus having the same
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-03-23
- Publication Date
- 2026-03-30
AI Technical Summary
Existing lens barrels face issues with lens groups moved manually or by external drive units interfering with those moved by electric drive units, leading to potential slipping and wear of piezoelectric actuators or tooth skipping in stepping motors, which deteriorate focus performance.
A lens barrel design that includes a first holding member for a first lens group, a second holding member for a second lens group, a transmission member, a drive unit, and a control unit that manages the drive unit based on the position of the first holding member, allowing the first lens group's movement within the second lens group's range, with a biasing member that can retract elastically to prevent interference and slipping.
Prevents deterioration of focus performance by allowing controlled movement of lens groups even with significant interference, minimizing clearance between lenses and maintaining a compact lens barrel design.
Smart Images
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Abstract
Description
[Technical field]
[0001] The present invention relates to a lens barrel, and more particularly to a lens barrel having a lens group that is moved manually or by an external drive unit and a lens group that is moved by an electrical drive unit. [Background technology]
[0002] Conventionally, in order to shorten the minimum overall length of a zoom lens, a configuration has been proposed that allows a lens group that is moved manually or by an external drive unit to enter within the movement range of a lens group (e.g., a focus lens group) that is moved by an electrical drive unit. Patent Document 1 discloses a configuration in which, when a first holding member that holds a first lens group interferes with a second holding member that holds a second lens group that moves according to the driving force of the drive unit, a biasing member is displaced to absorb the impact between the lens groups. Patent Document 1 also discloses a configuration in which the control of the drive unit is changed before the first holding member interferes with the second holding member. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] JP 2022-148164 A Summary of the Invention [Problem to be solved by the invention]
[0004] In the configuration of Patent Document 1, the driving unit is not controlled by further classifying cases when the first holding member and the second holding member are interfering with each other, but the driving unit is controlled so that the optical use area is always maintained. If the amount of interference is large, the biasing force of the biasing member becomes large. If the driving unit is driven in a state where the biasing force of the biasing member becomes large, if the driving unit is a piezoelectric actuator, the moving part will slip and wear will occur. Also, if the driving unit is a stepping motor connected to a lead screw, the transmission member will slip and teeth will jump. This will deteriorate the focusing performance.
[0005] The present invention aims to provide a lens barrel that has a configuration in which a lens group that is moved manually or by an external drive unit falls within the movement range of a lens group that is moved by an electrical drive unit, and that can suppress deterioration of focusing performance even when the amount of interference is large. [Means for solving the problem]
[0006] A lens barrel according to one aspect of the present invention has a first holding member that holds a first lens group movable in the optical axis direction, a second holding member that holds a second lens group movable in the optical axis direction, a transmission member that moves the second holding member in the optical axis direction, a drive unit that moves the transmission member in the optical axis direction, a control unit that controls the drive unit, and a first output unit that outputs information related to the position of the first holding member, wherein the range of movement of the first lens group can enter within the range of movement of the second lens group by a predetermined amount, and the second holding member has a biasing member that allows the transmission member to elastically retract by at least a predetermined amount to the opposite side of the first holding member in the optical axis direction, the lens barrel has a first state that restricts drive of the drive unit and a second state that permits drive of the drive unit, and the control unit determines whether the lens barrel is in the first state or the second state based on the output result of the first output unit. Effect of the Invention
[0007] According to the present invention, it is possible to provide a lens barrel that has a configuration in which a lens group that is moved manually or by an external drive unit falls within the movement range of a lens group that is moved by an electrical drive unit, and that is capable of suppressing deterioration of focusing performance even when the amount of interference is large. [Brief description of the drawings]
[0008] [Figure 1] FIG. 2 is a cross-sectional view of the lens barrel of the first embodiment. [Diagram 2] 4 is a diagram showing the movement locus of each lens in the first embodiment. FIG. [Diagram 3] FIG. 2 is an exploded perspective view showing the structure of a rack holding portion of the fourth group barrel. [Figure 4]FIG. 11 is a perspective view showing a state in which a rack is assembled to the fourth group barrel. [Diagram 5] 4 is a diagram showing the movement loci of the fourth lens group and the fifth lens group in Example 1. FIG. [Figure 6] FIG. 4 is a cross-sectional view of the fourth group barrel and the fifth group barrel in a normal state. [Figure 7] FIG. 4 is a cross-sectional view of the fourth group barrel and the fifth group barrel in an interference state. [Figure 8] FIG. 2 is a perspective view showing the state of the fourth group barrel and the rack in a normal state. [Figure 9] FIG. 13 is a perspective view showing the state of the fourth group barrel and the rack in an interference state. [Figure 10] FIG. 5 is a diagram for explaining a control method according to the present embodiment. [Figure 11] FIG. 11 is a diagram showing the force relationship in FIG. [Figure 12] FIG. 4 is a diagram illustrating an example of a method for determining whether a first state or a second state is present. [Figure 13] 10A and 10B are diagrams illustrating another example of a method for determining whether the first state or the second state is present. [Figure 14] 10A and 10B are diagrams illustrating another example of a method for determining whether the first state or the second state is present. [Figure 15] FIG. 2 is a diagram showing a rack and a lead screw. [Figure 16] FIG. 16 is a diagram showing the force relationship in FIG. [Figure 17] FIG. 11 is a diagram showing the movement locus of each lens in the second embodiment. [Figure 18] FIG. 13 is a diagram showing the movement trajectories of the fourth group barrel and the fifth group barrel in the second embodiment. [Figure 19] FIG. 6 is a diagram for explaining a conventional control method in FIG. [Figure 20] FIG. 20 is a diagram showing the force relationship in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to refer to the same components, and duplicated descriptions will be omitted. EXAMPLES
[0010] Fig. 1 is a cross-sectional view of the lens barrel of this embodiment. In Fig. 1, the line indicated by XX represents the optical axis. In this embodiment, the lens barrel is configured to be detachable from a camera body (imaging device) (not shown) that includes an imaging element that receives light from the lens barrel. The lens barrel may be configured integrally with the camera body.
[0011] The mount 101 is a component fixed to the camera body. The guide barrel 102 is fixed integrally to the mount 101 together with the fixed barrel 103. The cam ring 104 is held on the outer periphery of the guide barrel 102 so as to be rotatable around the optical axis. The zoom ring 105 is held on the outer periphery of the fixed barrel 103 so as to be rotatable, and is connected to the cam ring 104 by a key member (not shown). By operating the zoom ring 105 from outside, the cam ring 104 and the zoom ring 105 rotate integrally.
[0012] The zoom sensor 106 is attached to the fixed barrel 103, and obtains the zoom position (focal length information) by electrically detecting the rotation angle of the zoom ring 105, and outputs the obtained zoom position to a control board (control unit) 107. In this embodiment, the zoom sensor 106 functions as a first output unit. Note that, if the zoom sensor 106 can obtain the zoom position, it may detect, for example, the position of a five-group lens barrel 127 described later. The control board 107 is disposed near the mount 101, and is electrically connected to the zoom sensor 106, and obtains the zoom position from the zoom sensor 106. In addition, the control board 107 is electrically connected to a contact block 108, and communicates with the camera body and receives power from the camera body.
[0013] The first group lens L1 is fixed to a first group barrel 111. The first group barrel 111 is fixed to a rectilinear barrel 112.
[0014] The second group lens L2 is held by a second group barrel 113. The second group barrel 113 is held by a shift unit 114 so as to be movable within a plane perpendicular to the optical axis. The shift unit 114 includes an actuator for driving the second group barrel 113, a sensor for detecting the amount of drive of the second group barrel 113, and the like, and is fixed to the guide barrel 102. The shift unit 114 is electrically connected to a control board 107. The control board 107 controls the second group barrel 113 to correct shake based on a shake signal detected by a shake sensor 116 attached to the fixed barrel 103.
[0015] The third group lens L3 is held by a first portion group barrel 117 and a second portion group barrel 118, and is fixed to a third group base barrel 120. The electromagnetic diaphragm unit 121 is held by the third group base barrel 120, and is electrically connected to the control board 107.
[0016] The fourth lens group (second lens group) L4 is held by a fourth group barrel (second holding member) 122. The fourth group barrel 122 is held by a guide bar 123 to be movable in the optical axis direction on the third group base barrel 120. The fourth group lens L4 is a lens for focus adjustment (focus lens), and can be moved in the optical axis direction by a linear ultrasonic motor (piezoelectric actuator) 124 held by the third group base barrel 120.
[0017] The linear ultrasonic motor 124 includes a fixed part 125 and a movable part 126. The movable part 126 moves in the optical axis direction by ultrasonically vibrating the piezoelectric element. The piezoelectric element is electrically connected to the control board 107 by a flexible printed circuit board (not shown).
[0018] The fifth lens group (first lens group) L5 is held by a fifth lens group barrel (first holding member) 127.
[0019] The first group lens L1, the third group lens L3, and the fifth group lens L5 move during zooming. Cam followers (not shown) are fixed to the linear barrel 112, the third group base barrel 120, and the fifth group barrel 127. Each cam follower engages with a linear groove provided in the guide barrel 102 and a cam groove provided in the cam ring 104. When the cam ring 104 rotates, the linear barrel 112, the third group base barrel 120, and the fifth group barrel 127 move linearly in the optical axis direction.
[0020] Furthermore, since the fourth lens group L4 is held by the three-group base barrel 120, it moves in the optical axis direction by the linear ultrasonic motor 124 while moving together with the three-group base barrel 120 during zooming.
[0021] FIG. 2 is a diagram showing the movement locus of each lens from the collapsed state (SINK) to the telephoto state (TELE) with the mount 101 as a reference. The state from the wide-angle state (WIDE) to the telephoto state is the shooting state, and the state from the collapsed state to the wide-angle state is the non-shooting state in which the total lens length is shorter than that in the shooting state. L1, L2, L3, and L5 respectively show the movement loci of the first lens group L1, the second lens group L2, the third lens group L3, and the fifth lens group L5. The second lens group L2 does not move during zooming. L4 infinity shows the movement locus of the fourth lens group L4 when it is focused on infinity (infinity state). L4 closest shows the movement locus of the fourth lens group L4 when it is focused on the closest distance (closest state). At each focal length from the wide-angle state to the telephoto state, position information of the fourth lens group L4 that focuses on each focus position from infinity to the closest distance is stored. The linear ultrasonic motor 124 controls the fourth group barrel 122 based on the stored position information of the fourth group lens L4 and the zoom position acquired by the zoom sensor 106 so that the fourth group lens L4 follows the line shown in FIG.
[0022] The following describes the holding structure of fourth group barrel 122. Fig. 3 is an exploded perspective view showing the structure of a rack holding portion of fourth group barrel 122. Fig. 4 is a perspective view showing a state in which rack (transmission member) 131 is incorporated into fourth group barrel 122.
[0023] Shaft portion 131a of rack 131 is passed through rack spring (biasing member) 132, and then inserted between rack shaft holes 122a, 122b of fourth group barrel 122. Thereafter, rack guide shaft 133 is assembled so as to pass through rack shaft holes 122a, 122b and slide hole 131b of rack 131. Rack guide shaft 133 is fixed to fourth group barrel 122 without rattle by press-fitting an end portion into rack shaft hole 122a. With the above configuration, rack 131 is held so as to be movable in the optical axis direction relative to rack guide shaft 133 and rotatable around the axis of rack guide shaft 133.
[0024] Rack 131 is constantly urged in the Z direction shown in FIG. 4 parallel to the optical axis by the urging force of rack spring 132, and end 131c of rack 131 constantly abuts against fourth group barrel 122 on the side of rack shaft hole 122b.
[0025] Moreover, hook portion 132a of rack spring 132 is hooked on rack 131, and extension portion 132b on the opposite side is inserted into spring hook hole 122c provided in fourth group barrel 122. As a result, rack 131 is constantly biased in the Y direction shown in FIG. 4 with rack guide shaft 133 as the center of rotation.
[0026] Furthermore, a V-groove portion 131d at the tip of the rack 131 is constantly engaged with a protrusion (not shown) provided on the movable portion 126 of the linear ultrasonic motor 124. This makes it possible to transmit the driving force of the linear ultrasonic motor 124 to the fourth group barrel 122 without rattling due to the biasing force, even if there is variation in part precision.
[0027] In this embodiment, the second output section is configured by scale 134 adhesively fixed in a groove of fourth group barrel 122 and a position sensor (not shown) attached to the side of third group base barrel 120. A continuous pattern in the optical axis direction is formed on scale 134. The position sensor reads the pattern formed on scale 134 and detects the relative position of fourth group barrel 122 with respect to third group base barrel 120 in the optical axis direction. The detection result is output to control board 107.
[0028] Both ends of guide bars 123a and 123b are fixed to third group base barrel 120. Guide bar 123a is inserted into sleeve holes 122d and 122e provided in fourth group barrel 122, and holds fourth group barrel 122 movably in the optical axis direction. Guide bar 123b engages with U-shaped groove 122f of fourth group barrel 122, and prevents fourth group barrel 122 from rotating around guide bar 123a.
[0029] A method of moving the fourth group lens L4, which is a lens for focus adjustment, will be described below. FIG. 5 is a diagram showing the movement loci of the fourth group lens L4 and the fifth group lens L5 from the collapsed state to the telephoto state with the three-group base lens barrel 120 as a reference. L4 infinity indicates the movement locus of the fourth group lens L4 in a state focused at infinity. L4 closest indicates the movement locus of the fourth group lens L4 in the closest state. L5 indicates the movement locus of the fifth group lens L5. The distance between each line in the optical axis direction indicates the clearance between each group. Therefore, if the lines intersect, it indicates that the lens barrels interfere with each other.
[0030] As described above, position information of the fourth group lens L4 that focuses on each focus position from infinity to the closest distance is stored at each focal length from the wide state to the telephoto state. The linear ultrasonic motor 124 controls the fourth group barrel 122 so that the fourth group lens L4 follows the line shown in FIG. 4 based on the stored position information of the fourth group lens L4 and the zoom position acquired by the zoom sensor 106. Specifically, the linear ultrasonic motor 124 controls the fourth group barrel 122 so that the fourth group lens L4 follows the line indicated as L4 infinity during zooming in the infinity state. Also, the linear ultrasonic motor 124 controls the fourth group barrel 122 so that the fourth group lens L4 follows the line indicated as L4 closest distance during zooming in the closest distance state.
[0031] The fourth group barrel 122 is electrically controlled during zooming, but zooming is performed manually or by an external drive unit. Therefore, when zooming at high speed, there is a limit to the movement speed of the fourth group lens L4, and it may not be possible to keep up with the zooming. When zooming is performed by a built-in motor, the above problem does not occur by appropriately controlling the speed of the built-in motor.
[0032] In this embodiment, if the telephoto state is changed to the retracted state at high speed when the telephoto state is at the closest distance (telephoto closest state), the fourth group barrel 122 may not be able to move in time and may interfere with the fifth group barrel 127. In Figure 5, the range where interference is possible is shown as the interference region. When the amount of interference is maximum (predetermined amount) A, the positions of the fourth group barrel 122 and the fifth group barrel 127 are respectively the positions when the telephoto state is at the closest distance and the positions when the barrel is retracted.
[0033] In normal shooting conditions, the amount of interference depends on the zooming speed and the speed of the actuator of the focus lens. If the lens barrel is removed from the camera body in the telephoto close-up state and the power is cut off, the focus lens cannot move. In this case, if the state is changed to the retracted state, the fourth group barrel 122 and the fifth group barrel 127 will interfere with each other by a maximum amount A. That is, in the lens barrel of this embodiment, the movement range of the fifth group lens L5 can enter the movement range of the fourth group lens L4 by a maximum amount A.
[0034] The operation when the fourth group barrel 122 and the fifth group barrel 127 interfere with each other will be described below. Fig. 6 is a cross-sectional view of the fourth group barrel 122 and the fifth group barrel 127 in a normal state in which they do not interfere with each other. Fig. 7 is a cross-sectional view of the fourth group barrel 122 and the fifth group barrel 127 in an interference state in which the fourth group barrel 122 and the fifth group barrel 127 interfere with each other. Fig. 8 is a perspective view showing the state of the fourth group barrel 122 and the rack 131 in the normal state. Fig. 9 is a perspective view showing the state of the fourth group barrel 122 and the rack 131 in the interference state.
[0035] As shown in FIG. 7, when zooming is performed at high speed from the telephoto state, or when power is cut off in the telephoto close-up state and zooming is performed toward the retracted state, the abutment portion 122g of the fourth group barrel 122 and the abutment portion 127a provided on the fifth group barrel 127 come into contact with each other. As a result, the fourth group barrel 122 is pushed in the optical axis direction by the fifth group barrel 127. The rack 131 is held by the movable portion 126 of the linear ultrasonic motor 124, and the movable portion 126 is stationary due to frictional force with the fixed portion 125, so that the rack spring 132 is compressed and the rack guide shaft 133 slides. That is, the rack spring 132 is configured to be elastically retractable by a maximum amount A on the opposite side of the fifth group barrel 127 in the optical axis direction relative to the rack 131. The fourth group barrel 122 moves in the optical axis direction together with the fifth group barrel 127. This state is called the retracted state. Therefore, even if interference occurs, damage to the fourth group barrel 122, the fifth group barrel 127, the rack 131, and the linear ultrasonic motor 124 can be suppressed.
[0036] In conventional lens barrels, the optical design is such that no other lenses are placed within the range of movement of the electrically-driven focus lens. In other words, the clearance between other lenses that are placed so as not to interfere with the range of movement of the focus lens in the telephoto state is also provided in the wide-angle state. Since the amount of movement of the focus lens in the wide-angle state is often smaller than in the telephoto state, unnecessary clearance is often created, resulting in a long overall lens length.
[0037] In this embodiment, by using a configuration that allows interference of the focus lenses when performing high-speed zooming, it is possible to minimize unnecessary clearance between lenses and achieve a compact overall lens barrel.
[0038] A control method for the linear ultrasonic motor 124 will be described below. First, problems with the conventional control method for the linear ultrasonic motor 124 will be described with reference to Figs. 19 and 20. Fig. 19 is a diagram for explaining the conventional control method in Fig. 5. Fig. 20 is a diagram showing the force relationships in Fig. 19. Figs. 20(a) to 20(c) respectively show the force relationships when the fourth group lens L4 is located at positions P1, P3, and P4.
[0039] When the lens barrel is removed from the camera body in the telephoto close-up state (when the fourth lens group L4 is at position P1) and the power is cut off, and then the lens barrel changes to the retracted state, interference between the fourth lens group L4 and the fifth lens group L5 begins when the fifth lens group L5 reaches position P2. After that, the fourth lens group L4 and the fifth lens group L5 move to position P3.
[0040] In Fig. 20(a), the rack 131 and the fourth group barrel 122 are integrated by the biasing force 201 of the rack spring 132. In Fig. 20(b), the amount of interference is greatest and therefore the biasing force 201 is also greatest, but the rack 131 is held in place by the static friction force 211 between the movable part 126 and the fixed part 125 of the linear ultrasonic motor 124. That is, when the fourth group lens L4 is located at position P3, the static friction force 211 is greater than the biasing force 201. If the lens barrel is attached to the camera body and power is supplied with the fourth group lens L4 located at position P3, and then the state is changed to the wide state, when the fourth group lens L4 reaches position P4, it will deviate from the line indicated as L4 closest.
[0041] In the conventional control method, the linear ultrasonic motor 124 is driven so that the fourth lens group L4 returns to the position of the line indicated as close to L4 when the fourth lens group L4 deviates from the line indicated as L4. In this case, the static friction force 211 changes to the kinetic friction force 221, and therefore, in a state in which the fourth lens group L4 is located at the position P4, the biasing force 201 becomes larger than the kinetic friction force 221, and the movable part 126 slips, causing wear, and there is a concern that the focusing performance may deteriorate.
[0042] Hereinafter, a method for controlling the linear ultrasonic motor 124 of this embodiment will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a diagram for explaining the control method of this embodiment in Fig. 5. Fig. 11 is a diagram showing the force relationships in Fig. 10. Fig. 11(a) to Fig. 11(d) respectively show the force relationships when the fourth group lens L4 is located at positions P1, P3, P4, and P5.
[0043] 11(c), when the fourth lens group L4 is located at position P4, the biasing force 201 is greater than the kinetic friction force 221, but in this embodiment, the linear ultrasonic motor 124 is not driven. After the fourth lens group L4 reaches position P5 where the kinetic friction force 221 becomes greater than the biasing force 201, the linear ultrasonic motor 124 is driven to move the fourth lens group L4 to position P6. Thereafter, the fourth lens group L4 moves to position P7 in the wide state and the closest position (wide close state).
[0044] In the control method of this embodiment, the linear ultrasonic motor 124 is driven after the kinetic friction force 221 becomes larger than the biasing force 201. This prevents the movable part 126 from slipping, so no wear occurs and deterioration of the focusing performance can be suppressed.
[0045] Fig. 12 is a diagram for explaining a method for detecting the zoom position and focus position to determine whether the lens barrel is in the first state or the second state. In this embodiment, the first state is a state in which there is a possibility that the movable part 126 may slip from position P3 to position P5 in Fig. 10, and driving of the linear ultrasonic motor 124 is restricted. The second state is a state in which there is no possibility that the movable part 126 may slip, and driving of the linear ultrasonic motor 124 is permitted.
[0046] In this embodiment, the control board 107 can determine whether the lens barrel is in the first state or the second state according to the zoom position and focus position acquired based on the output results of the first output unit and the second output unit. In this embodiment, if it is determined to be in the first state, the linear ultrasonic motor 124 is not driven. Also, if it is determined to be in the second state and the focus position is not a desired position, the linear ultrasonic motor 124 is driven. In this embodiment, the first state and the second state are determined according to the position at which the movable part 126 does not slip even when the biasing force 201 is the largest, but the present invention is not limited to this. It may be determined according to a desired position when the fourth group lens L4 is in a wide state.
[0047] In this embodiment, the control board 107 judges whether the state is the first state or the second state according to the zoom position and the focus position, but the present invention is not limited to this. For example, as shown in FIG. 13, the state may be judged whether the state is the first state or the second state according to the zoom position. In this case, the control board 107 can make the judgment with less information. Also, as shown in FIG. 14, the state may be judged whether the lens barrel is in the first state or the second state according to the zoom position, the focus position, and the compression amount of the rack spring 132. In this case, since the judgment is made taking into consideration the compression amount of the rack spring 132, it is possible to more accurately determine the position where the movable part 126 does not slip. The compression amount of the biasing member can be obtained from, for example, the difference between the position of the rack 131 or the movable part 126 and the position of the fourth group barrel 122. In this case, a third output unit that detects the rack 131 and outputs the detection result to the control board 107 may be provided. Also, it can be obtained from the difference between the position of the fourth group barrel 122 when the power supply is cut off and the current position of the fourth group barrel 122. Furthermore, whether the lens barrel is in the first state or the second state may be determined based on the zoom position and the compression amount of the rack spring 132. Alternatively, whether the lens barrel is in the first state or the second state may be determined based on the zoom position and the compression amount of the rack spring 132.
[0048] Also, the fourth group barrel 122 may be moved to infinity, or may be moved to a desired position between the closest distance and infinity.
[0049] The same is true not only when the lens barrel is removed from the camera body and the power is cut off in the telephoto close-up state with the fourth lens group L4 at position P1, but also when the lens barrel changes to the retracted state after the power is turned off or when the lens barrel changes to the retracted state at high speed.
[0050] Also, in this embodiment, the direction of retreat is within the range of maximum amount A in Figure 5 and on the image side (image capture surface side) in the optical axis direction, but it may be on the object side or on both.
[0051] In this embodiment, a linear ultrasonic motor 124 is used to move the fourth group barrel 122, but other driving units such as a stepping motor may also be used. The effect of using a stepping motor will be described with reference to Figs. 15 and 16. Fig. 15 is a diagram showing a rack (transmission member) 231 and a lead screw 241. Fig. 16 is a diagram showing the relationship of forces in Fig. 15, showing the teeth of the rack 231 and the teeth of the lead screw 241 cut away.
[0052] The rack 231 is biased to the lead screw 241 by a biasing member (not shown), and the teeth of the rack 231 mesh with the teeth of the lead screw 241. When the lead screw 241 is rotated by a stepping motor (not shown), the rack 231 moves in the optical axis direction. In addition, a biasing force 201 is applied to the rack 231 from right to left on the page by the biasing member. The rack 231 moves integrally with the fourth group barrel 122 (not shown).
[0053] FIG. 18(a) shows the relationship of forces when the fourth lens group L4 is located at the position P4 in FIG. 10 and the stepping motor is not driven. In FIG. 18(a), the biasing force 201 becomes the biasing force 202 in the inclined surface direction, and the static friction force 211 is greater than the biasing force 202. When the stepping motor is driven from the state of FIG. 18(a), the biasing force 202 becomes greater than the kinetic friction force 221 as shown in FIG. 18(b), and the rack 231 starts to slide to the upper left in the inclined surface direction. Then, as shown in FIG. 18(c), tooth jumping occurs. In addition, the tip of the tooth of the rack 231 becomes rounded due to the tooth jumping, and the rack 231 becomes prone to tooth jumping. Therefore, by applying the control method of this embodiment to the stepping motor, the rack 231 does not slip, and the above problem can be solved.
[0054] In this embodiment, the interchangeable lens for taking still images and videos has been described, but the same effect may be obtained when performing manual zooming in a lens barrel for recording images. Also, the present invention is not limited to the focus lens in the lens barrel, but can be applied to other lenses that move during zooming, or to cases where the lens barrel is made smaller by abutting against a fixed part. EXAMPLES
[0055] In this embodiment, only the difference from the first embodiment will be described. In the first embodiment, a collapsible lens was described, but in this embodiment, a non-collapsible lens will be described. That is, in the first embodiment, the boundary between the first state and the second state is in the non-photographing state, but in this embodiment, the boundary between the first state and the second state is in the photographing state.
[0056] Fig. 17 is a diagram showing the movement locus of each lens from the collapsed state to the telephoto state with the mount 101 as the reference. L1, L2, L3, and L5 respectively show the movement loci of the first lens group L1, the second lens group L2, the third lens group L3, and the fifth lens group L5. L4 infinity shows the movement locus of the fourth lens group L4 in the infinity state. L4 closest shows the movement locus of the fourth lens group L4 in the closest state. Fig. 18 is a diagram showing the movement loci of the fourth lens group L4 and the fifth lens group L5 from the wide state to the telephoto state with the three-group base barrel 120 as the reference.
[0057] When the lens barrel is removed from the camera body in the telephoto close-up state (the state in which the fourth lens group L4 is located at position P1) and the power is cut off, and then the state is changed to the wide-angle state, interference between the fourth lens group L4 and the fifth lens group L5 begins when the fifth lens group L5 reaches position P2. After that, the fourth lens group L4 and the fifth lens group L5 move to position P3. When the fourth lens group L4 is located at position P3, it is in the first state, that is, the state in which the movable part 126 slides, so it is necessary to move the zoom position to position P4 where the movable part 126 does not slide. Therefore, when zooming is performed by a built-in motor, the zoom position is moved to position P4. Also, when zooming is performed manually, it is necessary to notify that it is a prohibited area where focus drive is restricted (the lens barrel is in the first state) and to have the zoom position moved to position P4. Therefore, a notification unit that notifies that the lens barrel is in the first state may be provided. After the fourth lens group L4 reaches position P4 where it is in the second state, the linear ultrasonic motor 124 is driven to move the fourth lens group L4 to position P5. In this way, even in a non-retractable lens, the driving of the linear ultrasonic motor 124 is restricted in the first state, and after the zoom position is moved and the state is changed to the second state, the driving of the linear ultrasonic motor 124 is permitted. This prevents the movable part 126 from slipping, so no wear occurs and deterioration of the focus performance can be suppressed.
[0058] The disclosure of this embodiment includes the following configuration.
[0059] (Configuration 1) a first holding member that holds a first lens group that is movable in the optical axis direction; a second holding member that holds a second lens group that is movable in the optical axis direction; a transmission member that moves the second holding member in the optical axis direction; a drive unit that moves the transmission member in the optical axis direction; A control unit that controls the drive unit; a first output unit that outputs information regarding a position of the first holding member, A lens barrel in which the movement range of the first lens group can enter into the movement range of the second lens group by a predetermined amount, the second holding member includes a biasing member that is elastically retractable by at least the predetermined amount to an opposite side to the first holding member in the optical axis direction with respect to the transmission member, the lens barrel has a first state in which drive of the drive unit is restricted and a second state in which drive of the drive unit is permitted, The lens barrel, wherein the control unit determines whether the lens barrel is in the first state or the second state based on an output result of the first output unit. (Configuration 2) The lens barrel according to configuration 1, wherein the lens barrel has a photographing state and a non-photographing state in which the overall length is shorter than that of the photographing state. (Configuration 3) 3. The lens barrel according to configuration 2, wherein the boundary between the first state and the second state is within the non-photographic state. (Configuration 4) 3. The lens barrel according to configuration 2, wherein the boundary between the first state and the second state is within the shooting state. (Configuration 5) The lens barrel described in configuration 4, further comprising a notification unit that notifies that the lens barrel is in the first state when the control unit determines that the lens barrel is in the first state. (Configuration 6) The lens barrel according to any one of configurations 1 to 5, wherein the driving section is a piezoelectric actuator. (Configuration 7) The lens barrel according to any one of configurations 1 to 5, wherein the drive unit is a stepping motor connected to a lead screw. (Configuration 8) Further, a second output unit that outputs information regarding the position of the second holding member, The lens barrel described in any one of configurations 1 to 7, characterized in that the control unit determines whether the lens barrel is in the first state or the second state using information regarding the position of the first holding member and information regarding the position of the second holding member. (Configuration 9) A third output unit that outputs information regarding a position of the transmission member, The lens barrel described in configuration 8, wherein the control unit determines whether the lens barrel is in the first state or the second state using information regarding the position of the first holding member, information regarding the position of the second holding member, and information regarding the position of the transmission member. (Configuration 10) A third output unit that outputs information regarding a position of the transmission member, The lens barrel described in any one of configurations 1 to 7, characterized in that the control unit determines whether the lens barrel is in the first state or the second state using information regarding the position of the first holding member and information regarding the position of the transmission member. (Configuration 11) the first lens group is a lens group that moves during zooming, The lens barrel according to any one of configurations 1 to 10, wherein the second lens group is a lens group that moves during focus adjustment. (Configuration 12) A lens barrel according to any one of configurations 1 to 11, and an image sensor that receives light from the lens barrel.
[0060] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]
[0061] 122 4th group lens barrel (second holding member) 124 Linear ultrasonic motor (drive unit) 127 5-group lens barrel (first holding member) 131 Rack (transmission member) 132 Rack spring (biasing member) L4 4th lens group (2nd lens group) L5 5th lens group (1st lens group)
Claims
1. A first holding member that holds a first lens group that is movable in the optical axis direction, A second holding member that holds a second lens group that is movable in the optical axis direction, A transmission member that moves the second holding member in the direction of the optical axis, A drive unit for moving the transmission member in the direction of the optical axis, It has a control unit that controls the drive unit, The movement range of the second lens group and the movement range of the first lens group overlap by a predetermined amount. The second holding member includes a biasing member that can be deformed by a predetermined amount or more in the direction opposite to the first holding member relative to the transmission member in the optical axis direction, The lens barrel is characterized in that the control unit determines, based on information regarding the position of the first holding member, whether it is in a first state where the driving of the drive unit is restricted or a second state where the driving of the drive unit is permitted.
2. The lens barrel according to Claim 1, characterized in that it is possible to switch between a shooting state and a non-shooting state in which the overall length is shorter than that of the shooting state.
3. The lens barrel according to claim 2, characterized in that it is possible to switch between the first state and the second state in the non-shooting state.
4. The lens barrel according to claim 2, characterized in that the first state and the second state can be switched in the shooting state.
5. The lens barrel according to claim 4, further comprising a notification unit that notifies the lens barrel of being in the first state when the control unit determines that the lens barrel is in the first state.
6. The lens barrel according to any one of claims 1 to 5, characterized in that the drive unit is a piezoelectric actuator.
7. The lens barrel according to any one of claims 1 to 5, characterized in that the drive unit is a stepping motor to which a lead screw is connected.
8. The device further includes a second output unit that outputs information regarding the position of the second holding member, The lens barrel according to any one of claims 1 to 5, characterized in that the control unit determines whether the lens barrel is in the first state or the second state using information regarding the position of the first holding member and information regarding the position of the second holding member.
9. The system further includes a third output unit that outputs information regarding the position of the transmission member, The lens barrel according to claim 8, characterized in that the control unit determines whether the lens barrel is in the first state or the second state using information regarding the position of the first holding member, information regarding the position of the second holding member, and information regarding the position of the transmission member.
10. The system further includes a third output unit that outputs information regarding the position of the transmission member, The lens barrel according to any one of claims 1 to 5, characterized in that the control unit determines whether the lens barrel is in the first state or the second state using information regarding the position of the first holding member and information regarding the position of the transmission member.
11. The aforementioned first lens group is a lens group that moves during zooming. The lens barrel according to any one of claims 1 to 5, characterized in that the second lens group is a lens group that moves when adjusting the focus.
12. A lens barrel according to any one of claims 1 to 5, An imaging device characterized by having an image sensor that receives light from the lens barrel.