Lens device, imaging apparatus, method for controlling lens device, and program

Abstract

To provide a lens device in which a movable range of a lens group that is electrically driven and a movable range of a lens group that moves manually or by external driving means overlap each other, the lens device achieving size reduction and improvement in drive accuracy and imaging quality.SOLUTION: A lens device comprises: movable first and second groups; first and second holding members that hold the first and second groups; driving means that electrically drives the second holding member; a transmission member that is movable relative to the second holding member in an optical axis direction and transmits a driving force to the second holding member; urging member that urges the second holding member toward the first holding member with respect to the transmission member; control means that controls the driving means; and first and second detection means that detect the positions of the first and second holding members. Movable ranges of the first and second holding members have interference areas that interfere with each other. The control means performs determination as to whether the interference area of the first and second holding members or a non-interference area based on results of detection performed by the first and second detection means, and changes the control of the driving means based on a result of the determination.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to a lens apparatus, an imaging apparatus, a control method for a lens apparatus, and a program. [Background technology]

[0002] In order to shorten the minimum overall length of a zoom lens barrel, a technique is known that enables a configuration in which a lens group that is moved manually or by an external driving means is included within the movable range of a lens group that is moved by an electrical driving means. Patent Document 1 discloses a lens device that includes a first lens group that is moved manually in the optical axis direction, and a second lens group that is moved by the driving force of a driving member via a transmission member. It discloses a barrel structure in which, when a second holding member that holds the second lens group interferes with the first holding member, a biasing member is displaced to absorb the impact of a collision between the lens groups.

[0003] Furthermore, Patent Document 2 proposes a method of changing the control of a stepping motor, which is a driving means, in order to prevent the feedback control from becoming unstable when the biasing member is displaced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-197617 A [Patent Document 2] JP 2017-227825 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a configuration in which a lens group that is moved manually or by an external driving means enters within the movement range of a lens group that is moved using an electrical driving means as described above, a retraction structure using a biasing member is used as in Patent Document 1. On the other hand, neither Patent Document 1 nor Patent Document 2 discloses a configuration in which a lens group enters without a retraction structure.

[0006] Therefore, an object of the present invention is to provide a compact lens device in which the movable ranges of an electrically driven lens group and a lens group moved manually or by an external driving means overlap, which achieves improved driving accuracy and improved imaging quality. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the lens device of the present invention comprises a first holding member that holds a first lens group that moves in an optical axis direction manually or by an external driving means, a second holding member that holds a second lens group that moves in the optical axis direction, a driving means that electrically drives the second holding member in the optical axis direction, a control means that controls the driving means, a first detection means that detects the position of the first holding member, and a second detection means that detects the relative position of the second holding member with respect to the first holding member, wherein the movable range of the first holding member and the movable range of the second holding member have an interference state in which the first holding member and the second holding member interfere with each other, and the control means changes the control method of the driving means based on the detection results of the first detection means and the second detection means. Effect of the Invention

[0008] According to the present invention, it is possible to provide a compact lens device barrel that achieves improved drive accuracy and improved imaging quality in a lens device in which the movable range of a lens group that moves under electrical control overlaps with the movable range of a lens group that moves manually or by external drive means. [Brief description of the drawings]

[0009] [Figure 1]1 is a cross-sectional view of a lens barrel embodying the present invention at the wide-angle end in an infinity focused state. [Diagram 2] 2 is a cross-sectional view of the lens barrel of FIG. 1 in a close-up focus state at the wide-angle end. [Diagram 3] 2 is a cross-sectional view of the lens barrel of FIG. 1 at the telephoto end in an infinity focused state. [Figure 4] 2 is a cross-sectional view illustrating a close-up focus state at the telephoto end of the lens barrel of FIG. 1. [Diagram 5] FIG. 4 is a diagram showing the movement locus of each lens during zooming. [Figure 6] FIG. 2 is an exploded perspective view showing the structure of a rack holding portion of the fourth group barrel. [Figure 7] FIG. 11 is a perspective view showing a state in which a rack is assembled to the fourth group barrel. [Figure 8] 1 is a diagram showing the movement trajectories of the fourth group barrel and the fifth group barrel based on the third group base barrel. [Figure 9] FIG. 2 is a cross-sectional view showing the fourth and fifth group barrels in their normal states. [Figure 10] FIG. 4 is a cross-sectional view showing the interference state between the fourth group barrel and the fifth group barrel. [Figure 11] FIG. 2 is a perspective view showing the fourth group barrel and the rack in a normal state. [Figure 12] FIG. 11 is a perspective view showing the fourth group barrel and the rack in an interference state. [Figure 13] FIG. 9 is a diagram showing an area in which control is switched in the diagram of FIG. 8. [Figure 14] FIG. 1 is a diagram showing an imaging device having a lens device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which the drawings may not be drawn to scale for ease of understanding.

[0011] A lens barrel according to an embodiment of the present invention will be described. Fig. 1 is a cross-sectional view showing a wide-angle infinity focusing state of a lens barrel embodying the present invention. Fig. 2 is a cross-sectional view showing a wide-angle close focusing state of the lens barrel of Fig. 1. Fig. 3 is a cross-sectional view showing a telephoto infinity focusing state of the lens barrel of Fig. 1. Fig. 4 is a cross-sectional view showing a telephoto close focusing state of the lens barrel of Fig. 1. The line indicated by XX in the figures represents the optical axis.

[0012] In Fig. 1, a mount 101 is a component fixed to a camera body (not shown). A guide barrel 102 is fixed integrally to the mount 101 together with a fixed barrel 103. A cam ring 104 is held on the outer periphery of the guide barrel 102 so as to be rotatable around the optical axis. The cam ring 104 is connected to a zoom ring 105, which is rotatably held on the outer periphery of the fixed barrel 103, by a key member (not shown), and is configured to rotate integrally with the guide barrel 102 by operating the zoom ring 105 from the outside.

[0013] The zoom sensor 106 as a first detection means is attached to the fixed barrel 103, and is a sensor that can electrically detect the rotation angle of the zoom ring 105. The zoom sensor 106 is electrically connected to a control board 107 disposed near the mount 101, and transmits focal length information during zooming to a control circuit. A contact block 108 is electrically connected to the control board 107, and the control board 107 communicates with and receives power from a camera body (not shown).

[0014] The lens barrel as the lens device 100 has a first lens group L1, a second lens group L2, a third lens group L3, a fourth lens group L4, and a fifth lens group L5 arranged in this order from the object side to the image side. The first lens group L1 is fixed to a first group barrel 111. The first group barrel 111 is fixed to a linear barrel 112.

[0015] The second lens group 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, and the shift unit 114 is fixed to the guide barrel 102. The shift unit 114 is electrically connected to a control board 107. The control board 107 drives and 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.

[0016] The third lens group L3 is held by a 3A group barrel 117 and a 3B group barrel 118, both of which are fixed to a 3 group base barrel 120. An electromagnetic diaphragm unit 121 is held in the 3 group base barrel 120 and is electrically connected to the control board 107.

[0017] The fourth lens group L4 as the second lens group is held by a fourth-group barrel 122 (second holding member), and the fourth-group barrel 122 is held by guide bars 123a and 123b (FIG. 7) on the third-group base barrel 120 so as to be movable in the optical axis direction. The fourth lens group L4 is a lens for focus adjustment, and is driven in the optical axis direction by a linear ultrasonic motor 124 held by the third-group base barrel 120.

[0018] The linear ultrasonic motor 124 is made up of a fixed part 125 and a movable part 126, and is a well-known technology that ultrasonically vibrates a piezoelectric element to drive the movable part 126 in the optical axis direction. The piezoelectric element is electrically connected to the control board 107 by a flexible printed circuit board (not shown).

[0019] The fifth lens group L5 serving as the first lens group is held by a fifth-group lens barrel 127 serving as a first holding member. The first lens group L1, the third lens group L3, and the fifth lens group L5 are each lenses that move during zooming, and 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 is engaged with a linear groove provided in the guide barrel 102 and a cam groove provided in the cam ring 104, and is configured to be able to move linearly in the optical axis direction by rotating the cam ring 104.

[0020] Furthermore, the fourth lens group L4 for focus adjustment is held by the three-group base barrel 120, and is therefore driven 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. 5 is a diagram showing the movement locus of each lens group during zooming. Figure 5 shows the movement trajectory from wide to telephoto based on mount 101, with L1, L3, and L5 moving with zooming and L2 not moving with zooming. L4 infinity shows the movement trajectory of the fourth lens group L4 when focused at infinity, and L4 close shows the movement trajectory when focused at a specified close distance.

[0022] Position information of the fourth lens group L4 that focuses on each object distance from infinity to a close distance at each focal length from the wide-angle end to the telephoto end is stored as data (table) in a control board 107 that serves as a control means. Based on the position information of the fourth lens group L4 that focuses on each object distance and focal length information detected by the zoom sensor 106, the fourth group barrel 122 is driven and controlled by a linear ultrasonic motor 124 so as to trace the line shown in FIG.

[0023] Next, the holding structure of the fourth group barrel 122 will be described. Fig. 6 is an exploded perspective view showing the structure of a rack holding portion of fourth-group barrel 122. Fig. 7 is a perspective view showing a state in which rack 131 is assembled to fourth-group barrel 122.

[0024] 6 and 7, rack 131 (transmission member) has shaft portion 131a passing through rack spring 132 (urging member) and inserted between rack shaft holes 122a, 122b of fourth group barrel 122. Rack guide shaft 133 is assembled therein 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 having an end portion press-fitted into rack shaft hole 122a. As described above, rack 131 is movable in the optical axis direction relatively to rack guide shaft 133 (fourth group barrel 122) within a predetermined range, and is further held rotatable about the axis of rack guide shaft 133.

[0025] 7 which is parallel to the optical axis, by the biasing force of rack spring 132, so that end portion 131c of rack 131 always abuts against rack shaft hole 122b side of fourth group barrel 122. In other words, by the biasing force of rack spring 132, fourth group barrel 122 is biased toward fifth group barrel 127 side (first holding member side) with respect to rack 131.

[0026] Also, 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. By doing so, rack 131 is constantly biased in the Y direction shown in FIG. 7 with rack guide shaft 133 as the center of rotation. Also, V-groove portion 131d at the tip of rack 131 is constantly engaged with a protrusion (not shown) provided on movable portion 126 of linear ultrasonic motor 124. As a result, even if there is variation in part precision, it is possible to transmit the driving force of linear ultrasonic motor 124 to fourth group barrel 122 without rattling due to the biasing force.

[0027] 6 is a part of the second detection means, and is a component on which a continuous pattern is formed in the optical axis direction, and is adhesively fixed to a groove in the fourth group barrel 122. This pattern is read by a position sensor (not shown) which is a part of the second detection means attached to the third group base barrel 120 side, and the relative position of the fourth group barrel 122 in the optical axis direction with respect to the third group base barrel 120 can be detected. These are collectively referred to as the second detection means in this embodiment. The relative position of the fourth group barrel 122 in the optical axis direction with respect to the third group base barrel 120, or the relative position of the fourth group barrel 122 in the optical axis direction with respect to the fifth group barrel 127 may be detected directly. Alternatively, it may be detected indirectly by detecting the rotation of the zoom ring and calculating the position of the fourth group barrel 122 (second holding part) from the detection result.

[0028] 7, both ends of each of guide bars 123a and 123b are fixed to third group base barrel 120. Guide bar 123a is inserted through 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 is engaged with U-shaped groove 122f of fourth group barrel 122, and prevents fourth group barrel 122 from rotating around guide bar 123a.

[0029] Next, a method for driving the focus lens according to the present invention will be described. 8 is a diagram showing the movement trajectories of the fourth group barrel 122 and the fifth group barrel 127 at zoom positions from wide to telephoto, with the third group base barrel 120 as the reference. The distance between each line in the optical axis direction, indicated by the dashed dotted line X, indicates the clearance between each group. Therefore, if the lines intersect, it indicates that the barrels will interfere with each other.

[0030] When the fourth group barrel 122, which is a focus lens, is focused at infinity by zooming, it is driven and controlled by a linear ultrasonic motor 124 so as to trace the solid line indicated as L4 infinity in Fig. 8. When the fourth group barrel 122 is focused at the closest point, it is driven and controlled so as to trace the dashed line indicated as L4 closest point in Fig. 8. Although not shown, for the intermediate position between infinity and the closest point, the trajectory between L4 infinity and L4 closest point is stored as data, and it is driven and controlled according to the stored data based on the focal length information from the zoom sensor 106 described above.

[0031] In Fig. 8, the four-group barrel 122, which is the focus lens, is electrically driven and controlled in response to zooming, but zooming is performed manually or by an external driving means. Therefore, when zooming at high speed, there is a limit to the driving speed of the focus lens, and it may not be possible to move to the appropriate focus position that changes with zooming in time. Note that when zooming is performed using a conventional built-in motor, the above problem does not occur by appropriately controlling the speed of the built-in motor.

[0032] In this lens, when zooming quickly to the wide-angle end state while in close focus at the telephoto end, the drive of the fourth group barrel 122 cannot keep up, and there is a possibility that the fourth group barrel 122 and the fifth group barrel 127 will interfere (contact) with each other. Figure 8 shows the range where interference is possible as the interference region. The maximum amount of interference is the amount of overlap in the optical axis direction between the wide-angle end position of the fifth group barrel 127 (line indicated by L5) and the position at the telephoto end close to L4, which is the amount indicated by A in Figure 8.

[0033] The amount of this interference depends on the zooming speed and the speed of the focus lens actuator in normal shooting conditions. When applied to an interchangeable lens, if the lens is removed from the camera when in focus at the telephoto end and the power is cut off, the focus lens cannot be driven, and if the lens is then returned to the wide-angle end, interference will occur by the amount shown in Figure 8 as A.

[0034] Next, the movement of fourth group barrel 122, which is a focus lens, when it interferes with fifth group barrel 127 will be described. Figures 9 and 10 are cross-sectional views showing an interference state between fourth group barrel 122 and fifth group barrel 127, with Figure 9 showing the normal state and Figure 10 showing the interference state. Figures 11 and 12 are perspective views showing the position of rack 131 in the normal state and in the interference state.

[0035] As shown in Fig. 10, when zooming from the telephoto end at high speed, or zooming to the wide-angle end with the power supply cut off in a state close to the telephoto end, the abutment portion 122g of the fourth group barrel 122 abuts against the abutment portion 127a provided on the fifth group barrel 127. As a result, the fifth group barrel 127 presses the fourth group barrel 122 in the optical axis direction (left side in Figs. 9 and 10). Then, since the rack 131 is held by the movable portion 126 of the linear ultrasonic motor 124 and cannot move, the rack spring 132 is compressed, and the rack guide shaft 133 slides against the rack 131 (movable portion 126), and the fourth group barrel 122 moves in the optical axis direction together with the fifth group barrel 127. Hereinafter, the compression of the rack spring 132 in this manner is also referred to as retraction, and this state is also referred to as the retracted state. Therefore, even if interference occurs, damage to the barrel, rack 131, or linear ultrasonic motor 124 can be prevented. When the focus lens completes tracking or the interference state is released by turning the power back on, the positional relationship between the fourth group barrel 122 and rack 131 is restored to the original normal state by the biasing force of the rack spring 132. Note that the predetermined range in which the rack 131 and the fourth group barrel 122 can move relatively in the optical axis direction is configured to be larger than the maximum length A in the optical axis direction of the interference area AR4 described later. In this way, the fourth group barrel 122 (second holding member) is configured to be elastically retractable by at least an amount of movement equal to or greater than the maximum interference amount A in the direction opposite to the optical axis of the fifth group barrel 127 (first holding member) relative to the rack 131 (transmission member).

[0036] In this embodiment, the rack guide shaft 133 that movably holds the rack 131 and the guide bar 123a that guides the fourth group barrel 122 in the optical axis direction are configured as separate parts. This allows a larger distance to be provided between the sleeve holes 122d and 122e that hold the guide bar 123a of the fourth group barrel 122 compared to the conventional technology that uses a common shaft member. As a result, it is possible to suppress the inclination of the fourth group barrel 122 and further improve the optical performance. In addition, since the force acting in the direction perpendicular to the shaft can be reduced at the engagement portion between the two holes and the guide bar, it is difficult for twisting due to frictional force to occur, and smooth driving is possible.

[0037] Furthermore, in this embodiment, the rack guide shaft 133 is held by the fourth group barrel 122 as a separate body from the rack 131. This prevents the shaft from protruding in front of or behind the lens holding member as the rack member moves, as opposed to the prior art in which the shaft of the rack member is extended forwards and backwards in the optical axis direction. As a result, there is no need to provide unnecessary space in front of or behind the holding portion of the rack member, making it possible to reduce the size of the entire lens barrel. In the prior art, a space of maximum interference amount A in FIG. 8 was required in front of or behind the rack holding portion. Therefore, the effect of implementing the present invention increases in proportion to the increase in the amount of retraction.

[0038] In conventional lens barrels, the optical design was such that no other lenses were placed within the driving range of the electrically driven focus lens. In other words, the same amount of clearance was provided at the wide-angle end as with other groups that were placed so as not to interfere with the moving range of the focus lens at the telephoto end. Since the amount of movement of the focus lens at the wide-angle end is often smaller than at the telephoto end, there is often unnecessary clearance, which increases the overall lens length by that amount.

[0039] This lens is configured to allow interference of the focus lens during high-speed zooming, minimizing unnecessary clearance between lens groups and achieving a compact lens barrel overall. With a conventional design, the lens group spacing would have to be increased by the amount of A in Figure 8, but with the configuration of the present invention, the overall length can be shortened by that amount.

[0040] On the other hand, consider the case where interference occurs when the fourth group barrel 122 is driven in a direction approaching the fifth group barrel 127. For example, this corresponds to the case where, at a zoom position closer to the telephoto end than the intermediate zoom position, zooming is performed at high speed toward the wide-angle end while focusing from a state where the focus is on a point other than the closest distance to the closest distance and then focusing toward the closest distance. The fourth group barrel 122 collides with the fifth group barrel 127 while a thrust is being generated in the direction approaching it. Therefore, the impact at the time of collision is large, which poses problems in terms of quality such as drive noise and drive accuracy.

[0041] Furthermore, in general, the linear ultrasonic motor uses a feedback control in which the position of the fourth group barrel, which is the movable part, is detected by a position sensor and control is performed based on the difference between the drive command position and the actual position. Note that, although the present embodiment describes feedback control based on position deviation, control may also be performed based on speed, acceleration, acceleration deviation, differentiation, or integration, or a combination thereof.

[0042] In such feedback control, when the fourth group barrel 122 is stationary at a specific position and the fifth group barrel 127 collides with it, the above-mentioned retracted state is entered. That is, in a state where the fourth group barrel 122 and the fifth group barrel 127 are in contact with each other, the position of the movable part 126 of the linear ultrasonic motor 124 remains unchanged, and the fourth group barrel 122 and the fifth group barrel 127 move while increasing the compression amount of the rack spring 132. In this case, the position of the fourth group barrel 122 obtained from the scale 134 and a position detection sensor (not shown) changes in accordance with the retraction amount (compression amount of the rack spring 132), but the command position (the position to be obtained from the scale 134 and a position detection sensor (not shown)) for the movable part 126 of the linear ultrasonic motor 124 to move the fourth group barrel 122 does not change. Therefore, the deviation between the command position and the actual position of the fourth group barrel 122 becomes large, so the control generates a large thrust to reduce the deviation. However, since the fourth group barrel 122 is in contact with the fifth group barrel 127 and cannot move to the side that would further narrow the gap between the fourth group barrel 122 and the fifth group barrel 127, oscillation may occur, potentially resulting in loud collision noises and drive noises. The following describes how these issues can be resolved and how precision and quality can be improved while still achieving product miniaturization.

[0043] Fig. 13 is a diagram showing an area where the control of the control means is changed at each position of the diagram in Fig. 8. Fig. 13 shows the movement trajectories of the fourth group barrel 122 and the fifth group barrel 127 based on the position of the third group base barrel 120, and shows that the fourth group barrel 122 and the fifth group barrel 127 come into contact with each other and retreat at the position of the interference area AR4. The range in which the fourth group barrel 122 can move by driving the linear ultrasonic motor 124 is the range B in Fig. 13, and in this embodiment, B is a wider range with a margin than the optically necessary range at the telephoto end. The range in which the fifth group barrel 127 can move is the range C in Fig. 13 (only the object side range is shown), and the range B in which the fourth group barrel 122 can move overlaps with the range A, resulting in an interference area.

[0044] The areas AR1, AR2, AR3, and AR4 in FIG. 13 respectively indicate the optical use area, the interference avoidance area, the immediate interference area, and the interference area, which will be described later. These areas are stored as areas defined for the zoom position and the focus position, for example, in the control means as a judgment table. The optical use area AR1 is an area sandwiched between the L4 infinity line and the L4 close line in FIG. 13. The interference avoidance area AR2 is an area indicated by diagonal lines sandwiched between the L4 close line and a solid curve in FIG. 13. The interference area AR4 is an area indicated by coloring in FIG. 13, and is an area in which the image side end of the movable range of the fourth group barrel 122 is the image side end, and the movement locus of the fifth lens group L5 is the object side end. The immediate interference area AR3 is an area sandwiched between the interference avoidance area AR2 and the interference area AR4. The movable range C of the fifth group barrel 127 and the movable range B of the fourth group barrel 122 have an interference area (curve M which is the object side boundary of the interference area AR4) where they interfere with each other.

[0045] A method of controlling the drive of the four-group barrel using different control means in each region will be described. The optical use area AR1 is an optically effective driving area, and is an area where the lens can focus on the subject distance (object distance) specified for the product within the zoom variable range. That is, the optical use area AR1 is an area where the zoom lens group moves to a zoom position from the wide-angle end to the telephoto end, and the focus lens group moves to a subject distance from the close end to the infinity end. In other words, in the optical use area AR1, the zoom lens group and the focus lens group are each in an effective imaging state that is effective for imaging.

[0046] Feedback control is performed in the optical use area AR1, and settings are made taking into consideration the quality of the drive noise during zooming and the positional accuracy of the drive. Unless there is interference during high-speed zooming or when the power is turned off, control is normally performed within this optical use area. The command value in this area is a position determined by the current zoom position and the previous object distance or a command value from the camera.

[0047] Next, the interference area AR4 will be described. The interference region is the range expressed as the maximum interference amount A at the wide-angle end in FIG. 8 (FIG. 13), for example, and in this range, interference between the fourth group barrel 122 and the fifth group barrel 127 actually occurs. That is, the movement limit on the image side of the fourth group barrel 122 is restricted by the fifth group barrel 127. Although it is shown as a region in FIG. 8 (FIG. 13), the fourth group barrel 122 is not located inside this range, and is actually located on the curve M, which is the object side boundary of the interference region AR4 shown in FIG. 13, and the rack spring 132 is in a compressed, retracted state. That is, in the interference region AR4, the fourth group barrel 122 can only be located on the curve M, but at each zoom position of the interference region AR4, the rack 131 can move to the structural image side end position by compressing the rack spring 132. Such a compressed state of the rack spring 132 corresponds to the region on the image side of the curve M of the interference region AR4.

[0048] In this state, because the fifth group barrel 127 is positioned there, the fourth group barrel 122 cannot move beyond the curve M toward the image side. Therefore, since feedback control based on the deviation of the actual position relative to the command signal will result in oscillation, control is performed using a feedforward controller. Alternatively, when driving within the interference region AR4, an upper limit value for the deviation input of the feedback control may be set. Alternatively, when driving within the interference region AR4, the driving speed and acceleration of the fourth group barrel 122 in feedback control may be controlled to be lower than in regions other than the interference region AR4, or to have a smaller maximum speed.

[0049] This range corresponds to cases where interference occurs due to high speed zooming or when the power is turned off, and as described above, the interference is controlled to move toward the optical use area AR1 and enters the interference avoidance area AR2.

[0050] Next, the interference avoidance area AR2 will be described. As described above, in the interference avoidance area AR2, when zooming is performed at high speed, control is performed so as not to enter the interference area AR4 as much as possible. In other words, even when high-speed zooming is performed, control is performed so as to avoid collision (interference, contact) between the fourth group barrel 122 and the fifth group barrel 127. That is, in the interference avoidance area AR2, a contact avoidance state is achieved in which contact between the fourth group barrel 122 and the fifth group barrel 127 is avoided. Control is performed to increase the feedback gain of the feedback controller above that of the optical use area AR1, and to increase the maximum speed and acceleration.

[0051] The command position at this time becomes the boundary value of the optical use area AR1 that corresponds to the current zoom position in the optical use area AR1, and if the camera enters the interference avoidance area AR2 from the optical use area AR1 side during high-speed zooming, it is controlled to return to the optical use area AR1 based on the above command value. The same command value is used when the camera was in the interference avoidance area AR2 when the power was turned on, or when the camera entered the interference avoidance area AR2 from the interference area AR4 side.

[0052] Finally, the control in the pre-interference region AR3 will be described. The control method in the pre-interference region AR3 differs depending on whether the vehicle enters the pre-interference region AR3 from the interference avoidance region AR2 (on the interference avoidance region side) or enters the pre-interference region AR3 from the interference region AR4.

[0053] The pre-interference region AR3 is a region where control is performed to mitigate the sound generated at the time of collision, the driving sound, and the degradation of the captured image quality when the lens enters the interference region AR4 (curve M) even if control is performed to prevent interference as much as possible in the interference avoidance region AR2. That is, the pre-interference region AR3 is in a pre-contact state just before the fourth group barrel 122 and the fifth group barrel 127 come into contact with each other. The specific control of the pre-interference region AR3 differs depending on whether the lens enters from the interference region AR4 side (via the interference region AR4) or from the interference avoidance region AR2 side (via the interference avoidance region AR2).

[0054] First, when entering the immediate interference area AR3 from the interference avoidance area AR2 side, the above-mentioned objective is achieved, and specific control may involve making the feedback gain of the feedback controller smaller than that of the optical use area AR1, or setting an upper limit for the deviation of the feedback control. Alternatively, a feedforward controller may be used to generate a driving force for moving to the optical use area AR1, or the same controller may be used to control the driving force to approach 0.

[0055] On the other hand, if the zoom lens enters from the interference area AR4, the feedback controller moves the zoom lens to the boundary value of the optical area corresponding to the current zoom position or to the command position input from the camera. Alternatively, the feedforward controller may generate a driving force to enter an area on the optical use area side (for example, the optical use area AR1 or the interference avoidance area AR2). If the zoom lens is in this position when the power is turned on, the above is the same as above.

[0056] By performing the above-described control, it is possible to provide a compact lens device that achieves improved drive accuracy, drive sound quality, and image quality in a lens device having a range in which the movement ranges of a lens group moved using an electrical drive means and a lens group moved manually or by an external drive means overlap.

[0057] To make the above explanation easier to understand, the change in control when high-speed zooming is performed in the telephoto end state will be explained below using several examples. For convenience, the case where the zoom ring 105 is rotated at a plurality of different speeds from the telephoto end to the wide-angle end will be explained using FIG.

[0058] First, high-speed zooming is performed at the telephoto end position Pt, and the zoom position and focus position are moved to position P1.

[0059] If the object distance does not change, it should move to position P2, but if zooming is performed quickly, the driving speed of movable section 126 (fourth group barrel 122) cannot keep up and it moves to position P1.

[0060] At the point where position P1 is reached, the lens enters interference avoidance area AR2, so the control parameters of the feedback controller are changed to increase the focus speed to avoid interference, and the lens moves to position P3, returns to the optical use area AR1, and then reaches position Pw.

[0061] Next, the case where even faster zooming is performed will be described. Due to high-speed zooming from the telephoto end position Pt, the lens moves to position P4 along a trajectory with a larger delay than the trajectory described above. From here, the lens enters the interference avoidance area AR2, so an attempt is made to avoid the collision by increasing the focus speed, but the driving speed of the movable part 126 (fourth group barrel 122) cannot keep up and the lens moves to position P5 and enters the immediate interference area AR3. In the immediate interference area AR3, the control is changed, such as reducing the feedback gain, setting an upper limit on the deviation, or switching from feedback control to feedforward control. This allows the control that prioritizes collision avoidance to prioritize avoiding oscillation caused by collision, reducing collision noise and vibration. In this state, the fourth group barrel 122 and the fifth group barrel 127 collide (position P6). The fourth group barrel 122 is pushed by the fifth group barrel 127 and moves to position P7, and the zoom position becomes the wide-angle end.

[0062] In this state, an interference state occurs, so a drive force is applied to the fourth group barrel 122 to move it to the immediate interference region AR3, causing it to move to position P8, entering the interference avoidance region AR2. It then moves to position P9, entering the optical use region AR1, and the control parameters of the feedback control change, or control switches to feedforward control, resulting in it reaching position Pw, which was originally intended to be moved to by zooming.

[0063] By detecting the zoom position and focus position in this way, the control means determines the area based on the zoom position and focus position, and changes the control based on the determined area. This makes it possible to avoid interference between the fourth group barrel 122 (focus lens group) and the fifth group barrel 127 (zoom lens group) as much as possible, and when it is not possible to avoid it, to avoid oscillation, reduce drive noise (collision noise) and vibrations during collision, and improve the quality of the captured image.

[0064] In this embodiment, the control method is changed based on a diagram determined from the zoom position and the position of the focus lens in the optical axis direction (based on the detection results of the position detection means), but this is not limited to this.

[0065] For example, the area itself may be changed based on not only the position but also the zoom speed (the movement speed of the zoom lens group). For example, when the zoom speed is fast, the pre-interference area AR3 may be made wider, or the control parameters in the interference avoidance area may be changed according to the speed.

[0066] In this embodiment, the control is changed by dividing the area into the optical use area AR1, the interference avoidance area AR2, the immediately preceding interference area AR3, and the interference area AR4, but the invention is not limited to this division.

[0067] For example, the area may be divided into two areas, such as an interference area AR4 and a non-interference area as the remaining area, and feedback control in the non-interference area and feedforward control in the interference area AR4 may be switched. In this case, the non-interference area is treated as a single area including the optical use area AR1, the interference avoidance area AR2, and the area just before interference AR3. That is, in the non-interference area, the fourth group barrel 122 and the fifth group barrel 127 are in a non-contact state where they are not in contact with each other. In this case, feedback control is performed on the non-interference area that includes the optical use area AR1, and feedforward control is performed on the side where interference occurs (interference area AR4), thereby making it possible to prevent the generation of loud drive noises and collision noises due to oscillation during interference.

[0068] Furthermore, the area may be divided into more than four areas, and the quality can be further improved by dividing the immediately preceding interference area into two and changing the control parameters. In other words, it is possible to further improve the quality by changing the control based on two or more areas defined based on the relationship between the zoom position and the focus position.

[0069] 8, an interference area exists on the imaging surface side in the optical axis direction of electrically driven four-group barrel 122, but an interference area may also exist on the object side of electrically driven four-group barrel 122. Also, an interference area may exist on both the imaging surface side and the object side.

[0070] In this embodiment, an ultrasonic motor is used to drive the focus lens, but the same effect can be obtained even if a driving means such as a step motor is used.

[0071] An imaging device that enjoys the effects of the present invention can be realized by an imaging device 300 (FIG. 14) having a lens device 100 of the embodiment and a camera device 200 having an image sensor 201 that captures an image formed by the lens device 100.

[0072] (Other Examples) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions. 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]

[0073] 106 Zoom sensor (first detection means) 107 Control board (control means) 122 Fourth group lens barrel (second holding member) 124 Linear ultrasonic motor (driving means) 125 Fixed portion (driving means) 126 Movable part (driving means) 127 5th group lens barrel (first holding member) 131 Rack (transmission member) 132 Rack spring (biasing member) 134 Scale (second detection means) L4: Fourth lens group (second lens group) L5: Fifth lens group (first lens group)

Claims

1. a first holding member that holds a first lens group that is moved in the optical axis direction manually or by an external driving means; a second holding member that holds a second lens group that moves in the optical axis direction; a driving means for electrically driving the second holding member in the optical axis direction; A control means for controlling the driving means; a first detection means for detecting a position of the first holding member; a second detection means for detecting a relative position of the second holding member with respect to the first holding member, an interference state in which the first holding member and the second holding member interfere with each other is provided within a movable range of the first holding member and a movable range of the second holding member, The lens device according to claim 1, wherein the control means changes a control method for the drive means based on detection results of the first detection means and the second detection means.

2. 2. The lens device according to claim 1, wherein the control means determines whether the first holding member and the second holding member are in a contact state or a non-contact state based on detection results of the first detection means and the second detection means, and changes a control method for the drive means based on the result of the determination.

3. 3. The lens device according to claim 2, wherein the control means controls the drive means by feedback control, and when the result of the determination is the contact state, an upper limit value is set for the input deviation.

4. The lens device according to claim 2 or 3, characterized in that the control means controls the driving means by feedback control, and when the result of the judgment is the contact state, switches to control at a slower speed than when the non-contact state is obtained.

5. 5. The lens device according to claim 2, wherein the control means controls the driving means by feedback control, and when the result of the judgment is the contact state, switches to a control that provides a lower acceleration than when the non-contact state is obtained.

6. 3. The lens device according to claim 2, wherein the control means controls the driving means by feedforward control when the result of the judgment is the contact state, and by feedback control when the result of the judgment is the non-contact state.

7. The lens device described in any one of claims 1 to 6, characterized in that the control means has a judgment table in which two or more states are defined for the position of the first holding member and the position of the second holding member, including a contact state in which the first holding member and the second holding member are in contact and a non-contact state in which they are not in contact, and changes the control method based on the judgment table.

8. The lens device described in any one of claims 1 to 7, characterized in that the control means determines, based on detection results of the first detection means and the second detection means, whether the positions of the first holding member and the second holding member are in an image capture effective state effective for image capture, or in a contact avoidance state in which contact between the first holding member and the second holding member is avoided, and changes a control method of the drive means based on the result of the determination.

9. The lens device according to claim 8, wherein the control means determines whether the contact avoidance state is present or a pre-contact state immediately before contact between the first holding member and the second holding member based on detection results of the first detection means and the second detection means, and changes a control method for the drive means based on the result of the determination.

10. 10. The lens device according to claim 9, wherein, when the second holding member is in the pre-contact state, the control means changes a control method of the drive means based on detection results of the first detection means and the second detection means, depending on whether the second holding member has changed from the contact avoidance state to the pre-contact state, or has changed from a contact state in which the first holding member and the second holding member are in contact with each other to the pre-contact state.

11. 11. The lens device according to claim 10, wherein the boundary between the contact avoidance state and the immediately-contact state changes based on a moving speed of the first holding member based on a detection result of the first detection means.

12. 12. The lens device according to claim 10, wherein in the contact avoidance state, control of the driving means is changed so as to increase the acceleration or maximum speed of the second holding member with respect to the imaging effective state.

13. 13. An imaging device comprising: a lens device according to claim 1; and an imaging element for capturing an image formed by the lens device.

14. A method for controlling a lens apparatus by the control means in the lens apparatus according to any one of claims 1 to 12.

15. A program which, when executed by a processor, causes the processor to execute the method for controlling a lens apparatus according to claim 14.

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