Lens device, imaging device, lens device control method, and program

Abstract

To provide a compact lens device that improves driving accuracy and imaging quality in the lens device having a range where a moving range of an electrically controlled lens group and a moving range of a lens group which is moved manually or by an external drive means overlap each other.SOLUTION: A lens device includes: a first group that is moved in an optical axis direction manually or by an external drive means; a second group that electrically moves in the optical axis direction; first and second holding portions respectively holding the first group and the second group; a driving portion that moves the second holding portion in the optical axis direction; a control portion that controls the driving portion; first and second detection portions respectively detecting positions of the first and second holding portions. Movable ranges of the first and second holding portions overlap each other in a region in the optical axis direction, and a position of the second holding portion in the optical axis direction corresponds to a position of a movable portion of the driving portion. The control portion changes control of the driving portion on the basis of detection results of the first and second detection portions before the second holding portion interferes with the first holding portion.SELECTED DRAWING: Figure 1

Description

[Background technology]

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

[0002] In order to shorten the overall length of a zoom lens barrel, a technique is known that allows a lens group that is moved manually or by an external drive unit to fit within the range of movement of a lens group that is moved by an electrical drive unit. Patent Document 1 discloses a lens device that includes a first lens group that is manually moved along the optical axis and a second lens group that is moved via a transmission member by the driving force of a drive member. It discloses that when a second holding member that holds the second lens group interferes with a first holding member that holds the first lens group, a biasing member is displaced to absorb the impact between the lens groups.

[0003] In addition, in a configuration similar to that of Patent Document 1, a method has been proposed in which the control of the stepping motor, which is the driving means, is changed to prevent the feedback control from becoming unstable when the biasing member is displaced (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-197617 [Patent Document 2] Japanese Patent Application Publication No. 2017-227825 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 drive means enters the movement range of a lens group that is moved by electric drive control, a buffer structure using a biasing member is employed 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 buffer structure.

[0006] Patent Document 2 relates to detecting changes caused by a collision and changing control after the collision, but there are still issues to be solved in terms of avoiding collisions as much as possible. Therefore, an object of the present invention is to provide a compact lens device that achieves improved drive accuracy and improved imaging quality in a lens device having a range in which the movement range of a lens group driven electrically and the movement range of a lens group moved manually or by external drive means overlap. [Means for solving the problem]

[0007] In order to achieve the above object, the lens device of the present invention comprises a first holding member that holds a first lens group that moves in a direction of an optical axis manually or by an external driving means, a second holding member that holds a second lens group that moves in the direction of the optical axis electrically, a driving means that moves the second holding member in the direction of the optical axis, a control means that controls the driving means, a first detection means that detects a position of the first holding member, and a second detection means that detects a position of the second holding member, wherein the movable ranges of the first holding member and the second holding member include an optical use area that is effective for imaging and an interference area that overlaps with each other in the direction of the optical axis, and the position of the second holding member in the direction of the optical axis corresponds to the position of a movable part of the driving means, and the control means determines, based on the detection results of the first detection means and the second detection means, the optical use area; the optical use area and The interference region of The control of the driving means is changed between the areas, and the change of the control of the driving means is In the optical use area Feedback control and In the area between Feedforward control and of Changes in gain in feedback control is larger in the area between them than in the optically used area. or Make it smallerChange, maximum speed in feedback control or acceleration is made larger in the region between them than in the optically used region. The present invention is characterized by including at least one of the following modifications. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a compact lens device that achieves improved drive accuracy and improved imaging quality in a lens device having a range in which the movement ranges of a lens group that is electrically controlled and a lens group that is moved manually or by an external drive means overlap. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of the lens device of Example 1 at the wide-angle end in a state where the lens device is focused on infinity. [Figure 2] FIG. 2 is a cross-sectional view of the lens apparatus of the first embodiment at the wide-angle end in a state where the lens apparatus is focused on a close distance. [Figure 3] 1 is a cross-sectional view of the lens apparatus of Example 1 at the telephoto end in an infinity focused state. [Figure 4] 1 is a cross-sectional view of a lens apparatus according to a first embodiment at a telephoto end in a close-up focusing state. [Figure 5] FIG. 4 is a diagram showing the movement locus of each lens group during zooming. [Figure 6] FIG. 10 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 7] FIG. 7 is a diagram showing an area where control is switched in the diagram of FIG. 6. [Figure 8] FIG. 10 is a cross-sectional view of the lens device of the second embodiment at the wide-angle end in a state where the lens device is focused on infinity. [Figure 9] FIG. 10 is a cross-sectional view of the lens device of the second embodiment at the wide-angle end in a state where the lens device is focused on a close distance. [Figure 10] 1 is a diagram showing an imaging device having a lens device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. [Example]

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

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

[0013] The zoom sensor 106 serving as the 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 the camera body (not shown).

[0014] The first lens group L1 is fixed to a first group barrel 111. The first group barrel 111 is fixed to a linearly moving barrel 112. 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.

[0015] The third lens group L3 is held by a group 3A barrel 117 and a group 3B barrel 118, both of which are fixed to a group 3 base barrel 120. An electromagnetic diaphragm unit 121 is held in the group 3A base barrel 120 and is electrically connected to the control board 107.

[0016] Fourth lens group L4, which serves as a second moving lens group, is held in a four-group barrel 122, and fourth lens group barrel 122, which serves as a second holding member, is held by a first guide bar (not shown) on three-group base barrel 120 so as to be movable in the optical axis direction. Fourth lens group L4 is a lens for focus adjustment, and is driven in the optical axis direction by a voice coil motor (hereinafter referred to as VCM) 124, which serves as driving means held by three-group base barrel 120.

[0017] The VCM 124 is composed of a coil provided on a fixed part 125 and a magnet provided on a movable part 126, and the movable part 126 is driven in the optical axis direction by electromagnetic force. The coil is electrically connected to the control board 107 by a flexible printed circuit board (not shown).

[0018] The fifth lens group L5, which serves as the first moving lens group, is held by a fifth-group lens barrel 127, which serves as a first holding member. The first lens group L1, the third lens group L3, and the fifth lens group L5 are 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 move linearly in the optical axis direction by rotating the cam ring 104 relative to the guide barrel 102. With this configuration, the positions of the first lens group L1, the third lens group L3, and the fifth lens group L5 in the optical axis direction are identified by rotation angle information (position information) from a zoom sensor (first detection means) 106 that electrically detects the rotation angle of the zoom ring 105.

[0019] Furthermore, the fourth lens group L4, which is used for focus adjustment, is held by the three-group base barrel 120 via the fourth-group barrel 122, and is therefore driven in the optical axis direction by the VCM 124 while moving together with the three-group base barrel 120 during zooming. In the present invention, a one-to-one correspondence is always maintained between the position of the movable part of the VCM 124, which serves as driving means, and the position of the fourth lens group L4 in the optical axis direction. In other words, no buffer structure such as an elastic member is interposed between the member that determines the position of the fourth lens group L4 in the optical axis direction and the movable part of the VCM 124.

[0020] FIG. 5 shows the movement trajectories of the first lens group L1, the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 during zooming when focusing at infinity and when focusing at close range, indicated by lines L1, L2, L3, L4 at infinity, L4 at close range, and L5, respectively.

[0021] 5 shows the movement trajectory from the wide-angle end to the telephoto end as viewed from mount 101, with L1, L3, and L5 indicating that they move with zooming and L2 indicating that they do not move with zooming. L4 infinity indicates the movement trajectory of the fourth lens group L4 when focused at infinity, and L4 closest indicates the movement trajectory when focused at a predetermined closest distance.

[0022] Position information of the fourth lens group L4 that focuses on each object distance from infinity to the closest distance at each focal length from the wide-angle end to the telephoto end is stored in the control means as data (table). 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 VCM 124 drives and controls the fourth-group barrel 122 so that it follows the line shown in FIG.

[0023] A scale on which a continuous pattern is formed for position detection is fixed to fourth-group barrel 122. This pattern is read by a position sensor (not shown) attached to the third-group base barrel 120 side, and the relative position of fourth-group barrel 122 in the optical axis direction with respect to third-group base barrel 120 is detected. In this way, the relative position of fourth-group barrel 122 with respect to third-group base barrel 120 is detected by second detection means composed of the scale on which the continuous pattern is formed, which is fixed to fourth-group barrel 122, and the position sensor attached to the third-group base barrel 120 side.

[0024] Furthermore, both ends of a first guide bar and a second guide bar (not shown) are fixed to the third-group base barrel 120. The first guide bar is inserted into a sleeve hole provided in the fourth-group barrel 122, and holds the fourth-group barrel 122 so that it can move freely in the optical axis direction. The second guide bar is engaged with a U-shaped groove in the fourth-group barrel 122, and prevents the fourth-group barrel 122 from rotating around the first guide bar. Next, a method for driving the focus lens according to the present invention will be described.

[0025] 6 is a diagram showing the movement trajectories of the fourth-group barrel 122 and the fifth-group barrel 127 at zoom positions from the wide-angle end to the telephoto end, with the third-group base barrel 120 as the reference. The distance between each line in the optical axis direction indicates the clearance (spacing) between the barrels of each lens group. Therefore, when the lines intersect, this indicates that the barrels interfere with each other, and that there is an overlap between the movable ranges of the fourth-group barrel 122 and the fifth-group barrel 127.

[0026] When the fourth-group lens barrel 122, which is a focus lens, is zoomed, it is driven and controlled by the VCM 124 so that it follows the line indicated as L4 infinity in Fig. 6 when focused at infinity. When focused at the closest distance, it is driven and controlled so that it follows the dashed line indicated as L4 closest distance in Fig. 6. Although not shown, for intermediate positions between infinity and the closest distance, the trajectory that follows between L4 infinity and L4 closest distance is stored as data, and it is driven and controlled in accordance with the stored data based on focal length information from the zoom sensor 106.

[0027] 6, the focus lens, or fourth-group barrel 122, is electrically driven and controlled in response to zooming, but zooming is performed manually or by external drive means. Therefore, when zooming at high speeds, there is a limit to the drive speed of the electrically driven focus lens, and the drive of the focus lens may not be able to keep up with the zoom drive speed achieved manually or by external drive means.

[0028] In this lens apparatus, when zooming quickly to the wide-angle end while in focus at the closest distance at the telephoto end, the fourth-group barrel 122 may not be able to keep up, potentially resulting in interference with the fifth-group barrel 127. Figure 6 shows the range of potential interference as the interference region. The maximum amount of interference is the amount of overlap along the optical axis between the wide-angle end position (WIDE) of the fifth-group barrel 127 (line indicated by L5) and the telephoto end position (TELE) at the closest distance of L4, and is the amount indicated by A in Figure 6.

[0029] Under normal shooting conditions, the amount of this interference depends on the zooming speed, either manually or via an external drive means, and the speed of the focus lens actuator. With an interchangeable lens, if the lens is removed from the camera and power is cut off while focused on the closest object at the telephoto end, the focus lens cannot be driven, and so if the lens is then returned to the wide-angle end, interference will occur by the amount shown in A in Figure 6.

[0030] The following describes what happens when the fourth-group barrel 122, which is a focus lens, interferes with the fifth-group barrel 127. Because the fourth-group barrel is driven by the VCM 124, the holding force is generally weak when it is not powered on. This is because the holding force comes from the frictional force of the fourth-group barrel 122 against the first and second guide bars described above. If the fifth-group barrel 127 collides with the fourth-group barrel 122 in this state, the fourth-group barrel 122 will move in the optical axis direction by the amount of interference, thereby retracting in the optical axis direction. The above applies when zooming is performed while the power is turned off.

[0031] On the other hand, if interference occurs when fourth group barrel 122 is being driven in a direction that moves it closer to fifth group barrel 127, it will collide with fourth group barrel 122 while a thrust is being generated in the direction that moves it closer to fifth group barrel 127. For this reason, the impact at the time of collision is large, which poses problems in terms of quality such as sound (quietness) and vibration (low vibration), and in terms of drive accuracy.

[0032] To drive the VCM, feedback control is often used, in which the position of the fourth-group barrel 122, which is the moving part, is detected by a position sensor, and drive control of the VCM 124 is performed based on the difference between the commanded drive position and the actual position. Note that while this embodiment describes feedback control based on position deviation, control may also be performed based on deviations in velocity or acceleration, or a combination of these.

[0033] In this type of feedback control, if the fourth group barrel 122 is stationary at a specific position and collides with the fifth group barrel 127, a large deviation occurs between the commanded position and the actual position, so a large thrust is generated to try to reduce the deviation. However, because it cannot move in a direction that would narrow the gap with the fifth group barrel 127, there is a possibility that a large driving noise or collision noise will be generated due to oscillation. The following explains how these issues can be resolved and how precision and quality can be improved while still achieving product miniaturization.

[0034] Figure 7 is a diagram showing regions where the control method by the control means, which will now be described, differs for each position within a plane defined by the relationship between the position of each group barrel in the optical axis direction and the zoom position, as shown in Figure 6. Figure 7 shows the movement trajectory of fourth group barrel 122 relative to third group base barrel 120, and indicates that interference between fourth group barrel 122 and fifth group barrel 127 can occur within interference region AR4. The range over which fourth group barrel 122 can move when driven by the VCM is range B in Figure 7, and in this embodiment, B is a wider range with a margin than the range optically necessary at the telephoto end (TELE in Figure 7).

[0035] In Figure 7, AR1, AR2, AR3, and AR4 respectively represent the optically usable area, interference avoidance area, near-interference area, and interference area, which will be described later. The optically usable area AR1 is the area sandwiched between the L4 infinity line and the L4 closest line in Figure 7. The interference avoidance area AR2 is the diagonally shaded area sandwiched between the L4 closest line and a solid curve in Figure 7. The interference area AR4 is the colored area in Figure 7, and is an area whose image-side end is the image-side end of the operating range of the fourth lens group and whose object-side end is the movement locus of the fifth lens group L5. The near-interference area AR3 is the area sandwiched between the interference avoidance area AR2 and the interference area AR4.

[0036] A method for controlling the drive of the four-group barrel using different control means in each region will be described. The optical use range AR1 is an optically effective driving range, and is the range within the zoom variable range where focusing can be achieved at the subject distance (object distance) specified for the product. In other words, the optical use range is the range where focusing can be achieved at subject distances from the close-up end to the infinity end by moving the focus lens group, relative to the zoom position from the wide-angle end to the telephoto end by moving the zoom lens group.

[0037] Feedback control is performed in the optical use area AR1, and settings are made taking into consideration the quality and precision of noise during zooming. Control is normally performed within this optical use area unless there is interference during high-speed zooming or when the power is turned off. The command value in this area is a position determined by the current zoom position and the immediately preceding object distance, or a command value from the camera.

[0038] Next, the interference area AR4 will be described. 6, for example, at the wide-angle end, the interference region is the range expressed as maximum interference amount A, and since interference actually occurs in this range, the image-side movement limit of fourth-group barrel 122 is restricted by fifth-group barrel 127. Although this figure shows it as a region, it is unlikely that fourth-group barrel 122 will be located within this range, and in reality it will be located on curve M, which is the object-side boundary of interference region AR4.

[0039] In this state, the fourth group barrel 122 cannot move beyond curve M toward the image side. Therefore, the feedback gain of the feedback controller, which is based on the deviation of the actual position from the command signal, is changed depending on whether the direction of interference occurs or the direction of interference cancellation. Specifically, the feedback gain when driving in the direction of interference is made smaller than when driving in the direction of interference cancellation. Alternatively, an upper limit on the deviation when driving in the direction of interference may be set. Additionally, in the interference region AR4, it is also possible to drive the lens to move toward the optical use region using feedforward control rather than feedback control.

[0040] This range applies when interference occurs due to high-speed zooming or when the power is turned off, but as mentioned above, the lens is controlled to move toward the optical use area AR1 and enters the interference avoidance area AR2.

[0041] Next, the interference avoidance area AR2 will be explained, and as mentioned above, this range is controlled so as to avoid entering the interference area AR4 as much as possible when zooming is performed at high speed. In other words, even when zooming at high speed, control is performed so that the fourth group barrel 122 and the fifth group barrel 127 do not collide (contact). 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.

[0042] The command position at this time is the boundary value of the optical use area AR1 that corresponds to the current zoom position in the optical use area AR1, and if, during high-speed zooming, the lens enters the interference avoidance area AR2 from the optical use area AR1 side, it is controlled to return to the optical use area AR1 based on the command value described above. The same command value is used if the lens was in the interference avoidance area AR2 when the power was turned on, or if it entered the interference avoidance area AR2 from the interference area AR4 side.

[0043] 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 or from the interference region AR4.

[0044] The pre-interference area AR3 is an area where control is performed to reduce noise and quality during a collision when the vehicle enters the interference area AR4 (curve M) even though control has been performed to minimize interference in the interference avoidance area AR2. The specific control for the pre-interference area AR3 differs depending on whether the vehicle enters from the interference area AR4 side (via the interference area AR4) or from the interference avoidance area AR2 side (via the interference avoidance area AR2).

[0045] First, when entering from the interference avoidance area AR2, 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 on the deviation of the feedback control. Alternatively, a feedforward controller may be used to generate a driving force to move into the optical use area AR1, or the same controller may be used to control the driving force to approach 0.

[0046] On the other hand, if the lens enters from the interference area AR4 side, the feedback controller moves the 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 AR1 side (for example, the optical use area AR1, the interference avoidance area AR2). If the lens was in this position when the power was turned on, the same as above applies.

[0047] By performing the above-described control, it is possible to provide a compact lens device that achieves improved drive accuracy and improved imaging quality in a lens device having a range in which the movement ranges of a lens group driven electrically and a lens group moved manually or by external drive means overlap.

[0048] To make the above explanation easier to understand, the following describes several examples of changes in control when high-speed zooming is performed at the telephoto end. For convenience, the following describes the case where the zoom ring 105 is rotated at multiple different speeds from the telephoto end to the wide-angle end, using Figure 7.

[0049] First, assume that high-speed zooming is performed at the telephoto end position Pt, and the zoom position and focus position move to position P1. 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.

[0050] When it reaches position P1, it enters the interference avoidance area AR2, so the control parameters of the feedback controller are changed to increase the focus speed to avoid interference, and it moves to position P3, returns to the optical use area AR1, and then reaches position Pw.

[0051] Next, the case where even faster zooming is performed will be described. Position Pt remains the same, but due to the high-speed zooming, the lens moves to position P4, tracing a path with a longer delay than the path described above. From here, the lens enters interference avoidance region AR2, and an attempt is made to avoid collision by increasing the focus speed. However, the drive speed of the movable part 126 (fourth-group barrel 122) cannot keep up with the high-speed zooming, and the lens moves to position P5, entering pre-interference region AR3. In pre-interference region AR3, control is changed by reducing the feedback gain, setting an upper limit on deviation, or switching from feedback control to feedforward control. This shifts priority from collision avoidance to collision-induced oscillation avoidance, 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, resulting in the wide-angle end zoom position.

[0052] In this state, an interference state occurs, so a drive force is applied to the fourth group barrel 122 to move it to the just-before-interference area AR3, causing it to move to position P8 and enter the interference avoidance area AR2. It then moves to position P9, entering the optical use area AR1, and the control parameters of the feedback controller are changed, causing it to reach position Pw, the position it was intended to move to during the original zooming operation.

[0053] By detecting the zoom position and focus position in this way, control is changed according to the area determined by the zoom position and focus position, which 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 if interference cannot be avoided, reduces drive noise (collision noise) and vibrations during collision, thereby improving the quality of captured images.

[0054] 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.

[0055] For example, the area itself may be changed (varied) depending not only on the position but also on the zoom speed. For example, if the zoom speed is fast, the area just before interference AR3 may be made wider, or the control parameters in the interference avoidance area may be changed depending on the speed.

[0056] In this embodiment, the control is changed by dividing the area into an optical use area AR1, an interference avoidance area AR2, a just-before-interference area AR3, and an interference area AR4, but the invention is not limited to this division.

[0057] For example, the area may be divided into two regions, such as an optical use region AR1 and a non-optical use region that is closer to the fifth lens group L5 (the first moving lens group) than the optical use region AR1, and the feedback controller and feedforward controller may be simply switched between them. In this case, the non-optical use region is treated as a single region, including the interference avoidance region AR2, the immediately preceding interference region AR3, and the interference region AR4. In this case, feedback control is applied to the side that includes the optical use region AR1, and feedforward control is applied to the side where interference is occurring, thereby preventing the generation of loud drive noises or collision noises due to oscillation when interference occurs.

[0058] Furthermore, the area may be divided into more than four areas, and the quality can be further improved by dividing the area into two just before interference areas and changing the control parameters. In other words, it is possible to further improve quality by changing the control based on two or more areas defined based on the relationship between the zoom position and the focus position. Furthermore, in this embodiment, feedback control is performed based on the position deviation, but control may be performed based on the integral or derivative thereof, or a combination thereof. [Example]

[0059] Figure 8 is a cross-sectional view of the lens device of Example 2 at the wide-angle end, showing the state where the lens device is focused on infinity. Figure 9 is a cross-sectional view of the lens device of Figure 8 at the wide-angle end, showing the state where the lens device is focused on a close distance. The line XX in the figure represents the optical axis. The movement of each group is the same as in Example 1, so a description thereof will be omitted.

[0060] In the first embodiment, the driving source for driving the fourth group barrel 122, which is the focus group, is a voice coil motor, but in the second embodiment, the driving source is a friction drive motor that drives the focus group by frictional contact.

[0061] A friction drive motor (vibration wave motor) refers to a motor that moves a movable part by generating a traveling wave, such as an ultrasonic motor, or a motor that moves a movable part in the optical axis direction by expanding and contracting a piezoelectric element, but this embodiment will explain an ultrasonic motor. The ultrasonic motor 224 consists of a fixed part 225 and a movable part 226, and vibrates the piezoelectric element to drive the movable part 226 in the optical axis direction.

[0062] The major difference from the first embodiment is that when the drive source is a VCM, the holding force is only the friction between the guide bar and the focus group, whereas in the case of a friction drive motor, friction force is generated in the drive unit itself.

[0063] Because of this configuration, if interference occurs between the focus group and zoom group during high-speed zooming, the frictional parts may be dragged, causing wear at the contact points of the moving parts. This is where it differs from VCM. Below we explain how we use control to resolve these issues and achieve improvements in precision and quality while also enabling product miniaturization.

[0064] In the second embodiment, as in the first embodiment, the optical use region AR1, the interference avoidance region AR2, the pre-interference region AR3, and the interference region AR4 are divided into different regions as described in FIG. 7 , and the control method is changed accordingly. Detailed descriptions of each region will be omitted while referring to FIG. 7 . The following description will focus on control in the pre-interference region AR3, which is unique to the first embodiment. In the second embodiment, the fourth group barrel 122 is driven by an ultrasonic motor 224. The pre-interference region AR3 is a region where control is performed assuming that interference may enter the interference region AR4 (curve M) even if control is performed to minimize interference in the interference avoidance region AR2. In other words, this region is a region where control is performed to reduce noise during collisions, improve quality, and further improve the durability of the friction portions of the ultrasonic motor 224. The specific control of the pre-interference region AR3 differs depending on whether the region is entered 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).

[0065] First, when entering from the interference avoidance area AR2, the above-mentioned objective is achieved, and specific control may be performed by making the feedback gain of the feedback controller smaller than that of the optical use area AR1, or by setting an upper limit on the deviation of the feedback control. Alternatively, control may be performed such that a drive force to move into the optical use area AR1 is generated by a feedforward controller, or the drive force is made to approach zero by standing wave drive.

[0066] On the other hand, if the lens enters from the interference area AR4 side, the feedback controller moves the lens to the boundary value of the optical area corresponding to the current zoom position or to the command position from the camera (focus command position from an external device). Alternatively, the feedforward controller may generate a driving force that puts the lens into the interference avoidance area AR2. If the lens is in this position when the power is turned on, the same as above. Control in other areas is the same as in the first embodiment, so a description thereof will be omitted.

[0067] By performing the above-described control, it is possible to achieve improvements in precision and quality while also reducing the size of the product in a lens barrel in which a lens group that is moved manually or by external drive means enters the movement range of a lens group that is moved using electrical drive means.

[0068] In the case of the friction drive motor of this embodiment, if interference occurs when the power is turned off, there is a possibility that the friction points of the ultrasonic motor 224 will be rubbed. To avoid this, when turning off the power, it is possible to control the power so that the position of the focus group is moved to a position where no interference occurs regardless of the zoom position before turning off the power.

[0069] In the first and second embodiments, the control of a VCM and a friction drive motor that obtains drive thrust by electromagnetic force has been described, but other drive motors or a combination of these may also be used. For example, in a configuration where a VCM is used as the drive source but a friction unit is provided separately, it is possible to divide the regions as described above and change the control of the VCM friction unit.

[0070] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the 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 realizes one or more functions.

[0071] An imaging device that enjoys the effects of the present invention can be realized by an imaging device 300 (Figure 10) that includes the lens device 100 of the embodiment and a camera device 200 that has an imaging element 201 that captures the image formed by the lens device 100. 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]

[0072] 106 Zoom sensor (first detection means) 107 Control board (control means) 122 4th group lens barrel (second holding member) 124 Voice coil motor (drive means) 125 Fixed part (driving means) 126 ···· Movable part (driving means) 127 5th group lens barrel (first holding member) 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 direction of the optical axis manually or by an external driving means; a second holding member that holds a second lens group that is electrically moved in the direction of the optical axis; a driving means for moving the second holding member in the direction of the optical axis; a control means for controlling the driving means; a first detection means for detecting the position of the first holding member; a second detection means for detecting the position of the second holding member, a movable range of the first holding member and a movable range of the second holding member include an optical use area effective for imaging and an interference area overlapping with each other in the direction of the optical axis, a position of the second holding member in the direction of the optical axis corresponds to a position of a movable part of the driving means, the control means changes the control of the drive means between the optical use region and a region between the optical use region and the interference region based on the detection results of the first detection means and the second detection means, The change in control of the driving means includes at least one of a change between feedback control in the optical use region and feedforward control in the intermediate region, a change to make the gain in feedback control larger or smaller in the intermediate region than in the optical use region, and a change to make the maximum speed or acceleration in feedback control larger in the intermediate region than in the optical use region.

2. 2. The lens device according to claim 1, wherein the control means performs feedback control in the optical use region and performs feedforward control in the intermediate region.

3. a first holding member that holds a first lens group that is moved in the direction of the optical axis manually or by an external driving means; a second holding member that holds a second lens group that is electrically moved in the direction of the optical axis; a driving means for moving the second holding member in the direction of the optical axis; a control means for controlling the driving means; a first detection means for detecting the position of the first holding member; a second detection means for detecting the position of the second holding member, a movable range of the first holding member and a movable range of the second holding member include an optical use area that is effective for imaging and an optical non-use area that is located closer to the first lens group than the optical use area, a position of the second holding member in the direction of the optical axis corresponds to a position of a movable part of the driving means, The lens device is characterized in that the control means performs feedback control in the optical use area and performs feedforward control in the non-optical use area.

4. 2. The lens device according to claim 1, wherein the control means performs feedback control in the interference region, and the gain when driving in a direction in which the first holding member and the second holding member interfere with each other is smaller than the gain when driving in a direction in which the interference is released.

5. 2. The lens device according to claim 1, wherein the control means performs feedback control in the interference region and sets an upper limit value for the deviation when the first holding member and the second holding member are driven in a direction in which they interfere with each other.

6. 2. The lens device according to claim 1, wherein the control means performs feedforward control in the interference region, and controls the interference region to move toward the optical use region.

7. The lens device according to claim 1, wherein the control means, when entering the just-before-interference region in the region between the optical use region and the intermediate region from the optical use region, performs feedback control with a smaller gain than the optical use region, performs feedback control with an upper limit value set for the deviation, or performs feedforward control to move to the optical use region.

8. 2. The lens device according to claim 1, wherein the control means, when moving from the interference area to the just-before-interference area within the area between the interference area and the optical use area, performs feedback control using a boundary value with respect to the optical use area at the current zoom position or a focus command position input from outside as a command position in the just-before-interference area, or performs feedforward control to move to an area on the optical use area side.

9. The lens device according to any one of claims 1, 2, 4 to 8, characterized in that in an interference avoidance region between the immediately preceding interference region and the optical use region in the region between, the control means performs feedback control with a greater gain than in the optical use region, or performs feedback control with a greater maximum speed or greater acceleration than in the optical use region, using a boundary value with respect to the optical use region at the current zoom position as a command position.

10. 10. The lens device according to claim 9, wherein the boundary between the just-interference region and the interference avoidance region changes based on the detection result of the first detection means.

11. 11. The lens device according to claim 1, wherein the driving means is a voice coil motor.

12. the driving means is a vibration wave motor, The lens device according to any one of claims 1, 2, 4 to 10, characterized in that when the control means enters the just-before-interference region of the region between the optical use region and the intermediate region from the optical use region side, the control means performs feedback control with a smaller gain than the optical use region, performs feedback control with an upper limit value set for the deviation, performs standing wave drive, or performs feedforward control to move to the optical use region.

13. the first lens group is a lens group that moves for zooming, the second lens group is a lens group that moves for focus adjustment, 13. The lens device according to claim 1, wherein the optical use area is an area in which the first lens group moves to zoom positions from the wide-angle end to the telephoto end, and the second lens group moves to focus on an object distance from the close-up end to the infinity end.

14. 14. The lens device according to claim 1, wherein the position of the second holding member detected by the second detection means is a relative position of the second holding member with respect to the first holding member.

15. An imaging device comprising: a lens device according to any one of claims 1 to 14; and an imaging element for capturing an image formed by the lens device.

16. a first holding member that holds a first lens group that moves in a direction of an optical axis manually or by an external drive means; a second holding member that holds a second lens group that moves in the direction of the optical axis electrically; and a drive means that moves the second holding member in the direction of the optical axis, wherein the movable ranges of the first holding member and the second holding member include an optical use area that is effective for imaging and an interference area that overlaps with each other in the direction of the optical axis, and the position of the second holding member in the direction of the optical axis corresponds to the position of a movable part of the drive means, changing control of the driving means between the optical use area and an area between the optical use area and the interference area based on a position of the first holding member and a position of the second holding member; A control method characterized in that the change in control includes at least one of a change between feedback control in the optical use region and feedforward control in the intermediate region, a change to make the gain in feedback control larger or smaller in the intermediate region than in the optical use region, and a change to make the maximum speed or acceleration in feedback control larger in the intermediate region than in the optical use region.

17. A program causing a processor to execute the control method according to claim 16.

Images