Lens device, imaging device, lens device control method, 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 moved manually or by an external drive means is positioned within the movable range of a lens group moved using an electrical drive means. 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 also discloses a lens 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] 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] As described above, in a configuration in which a lens group moved manually or by an external driving means enters within the movement range of a lens group moved using an electrical driving means, a retraction 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 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 external drive means overlap, and which achieves improved drive accuracy and improved imaging quality. [Means for solving the problem]

[0007] In order to achieve the above object, the lens device of the present invention includes 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, and Feedback control Do a control means, a first detection means for detecting a position of the first holding member, and a second detection means for detecting a relative position of the second holding member with respect to the first holding member; The control means determines whether the first and second holding members are in a contact state where they are in contact with each other or in a non-contact state where they are not in contact with each other based on the detection results of the first and second detection means, and when it determines that they are in the contact state, performs one of the following control in the feedback control: control to set an upper limit value for the input deviation; control to drive at a lower speed than when it determines that they are in the non-contact state; or control to drive at a lower acceleration than when it determines that they are in the non-contact state. It is characterized by: [Effects 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 by electrical control overlaps with the movable range of a lens group that moves manually or by external drive means. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a lens barrel according to an embodiment of the present invention at the wide-angle end in a state focused on infinity. [Figure 2]2 is a cross-sectional view of the lens barrel of FIG. 1 at the wide-angle end in a state where the lens barrel is in close focus. [Figure 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. [Figure 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. 10 is a perspective view showing the state in which a rack is assembled to the fourth-group barrel. [Figure 8] This 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. 10 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 lens barrel and rack in a normal state. [Figure 12] FIG. 10 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] 1 is a diagram showing an imaging device having a lens device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[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 clarity.

[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 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, which serves 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 the 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 rectilinear 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 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.

[0017] The fourth lens group L4 as the second lens group is held by a four-group barrel 122 (second holding member), and the fourth group barrel 122 is held by guide bars 123a and 123b (FIG. 7) on the three-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 three-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 based on well-known technology, which causes a piezoelectric element to ultrasonically vibrate and drives 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, which serves as the first 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 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 as viewed from 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 closest shows the movement trajectory when focused at a specified 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 as data (table) in a control board 107 that serves as 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 linear ultrasonic motor 124 drives and controls the fourth-group barrel 122 so that it follows 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 the 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 passed through rack spring 132 (biasing member) and inserted between rack shaft holes 122a and 122b of fourth-group barrel 122. Rack guide shaft 133 is then assembled therein so as to pass through rack shaft holes 122a and 122b and slide hole 131b of rack 131. Rack guide shaft 133 is fixed to fourth-group barrel 122 without rattle by press-fitting its end into rack shaft hole 122a. As described above, rack 131 is movable in the optical axis direction relative to rack guide shaft 133 (fourth-group barrel 122) within a predetermined range, and is also 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 131c of rack 131 is always in contact with rack shaft hole 122b of fourth group barrel 122. In other words, the biasing force of rack spring 132 biases fourth group barrel 122 toward fifth group barrel 127 (first holding member side) relative to rack 131.

[0026] Furthermore, hook portion 132a of rack spring 132 is hooked onto 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 rotation center. Furthermore, V-shaped 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, the biasing force makes it possible to transmit the driving force of linear ultrasonic motor 124 to fourth-group barrel 122 without rattle.

[0027] 6 is 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 in a groove in the fourth-group barrel 122. This pattern is read by a position sensor (not shown) that is 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 components 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, the rotation of the zoom ring may be detected and the position of the fourth-group barrel 122 (second holder) may be calculated from the detection results, thereby performing indirect detection.

[0028] 7 are fixed at both ends 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 so that it can move freely in the optical axis direction. Guide bar 123b is engaged with U-shaped groove 122f in 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 loci 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 the groups. Therefore, when the lines intersect, it indicates that the barrels will interfere with each other.

[0030] When zooming, the four-group lens barrel 122, which is a focus lens, is driven and controlled by a linear ultrasonic motor 124 so that, when focused at infinity, it follows the solid line indicated as L4 infinity in Fig. 8. When focused at the closest point, it is driven and controlled so that it follows the dashed line indicated as L4 closest point in Fig. 8. Although not shown, for intermediate positions between infinity and the closest point, the trajectory that follows between L4 infinity and L4 closest point 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 described above.

[0031] In Figure 8, the focus lens, or fourth-group barrel 122, is electrically driven and controlled in response to zooming, but zooming is performed manually or by an external drive unit. Therefore, when zooming at high speeds, there is a limit to the drive speed of the focus lens, and it may not be able to move quickly enough to the appropriate focus position that changes with zooming. Note that when zooming using a conventional built-in motor, the above problem does not occur if the speed of the built-in motor is appropriately controlled.

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

[0033] The amount of this interference, under normal shooting conditions, depends on the zooming speed and the speed of the focus lens actuator. When applied to an interchangeable lens, if the lens is removed from the camera while in focus at the closest distance 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 A in Figure 8.

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

[0035] As shown in Fig. 10, when zooming at high speed from the telephoto end, or when zooming toward the wide-angle end with the power turned off while the lens is very close to the telephoto end, abutment portion 122g of fourth-group barrel 122 abuts against abutment portion 127a provided on fifth-group barrel 127. As a result, fourth-group barrel 122 is pushed in the optical axis direction (left side in Figs. 9 and 10) by fifth-group barrel 127. Then, because rack 131 is held by movable portion 126 of linear ultrasonic motor 124 and cannot move, rack spring 132 is compressed, and rack guide shaft 133 slides relative to rack 131 (movable portion 126), and fourth-group barrel 122 moves in the optical axis direction together with fifth-group barrel 127. Hereinafter, this compression of rack spring 132 will be referred to as retraction, and this state will also be 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. Once the focus lens has completed 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 returns to its original normal state due to the biasing force of rack spring 132. The predetermined range over which rack 131 and fourth group barrel 122 can move relative to each other in the optical axis direction is configured to be larger than the maximum length A of interference area AR4, which will be described later. In this way, the fourth group barrel 122 (second holding member) is configured to be elastically retractable relative to rack 131 (transmission member) in the opposite direction of the optical axis from the fifth group barrel 127 (first holding member) by an amount of movement at least equal to the maximum interference amount A.

[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 for a larger distance between the sleeve holes 122d and 122e that hold the guide bar 123a of the fourth-group barrel 122 compared to conventional technology that uses a common shaft member. As a result, tilting of the fourth-group barrel 122 is suppressed, and optical performance can be further improved. Furthermore, because the force acting in the direction perpendicular to the shaft can be reduced at the mating portion between the two holes and the guide bar, prying due to friction is less likely to occur, enabling smooth drive.

[0037] Furthermore, in this embodiment, the rack guide shaft 133 is held by the fourth-group barrel 122 as a separate member 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 prior art in which the shaft of the rack member extends forward and backward 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 prior art, a space corresponding to the maximum interference amount A in Figure 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 amount of retraction.

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

[0039] This lens is designed to allow interference between the focus lenses during high-speed zooming, thereby minimizing unnecessary clearance between lens groups and achieving a compact overall lens barrel. While a conventional design would require an increase in the distance between lens groups by the amount indicated by A in Figure 8, the configuration of this invention makes it possible to reduce the overall length by that amount.

[0040] Now, consider the case where interference occurs when the fourth-group barrel 122 is being driven in a direction that brings it closer to the fifth-group barrel 127. For example, this occurs when, 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 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 that brings it closer to the fifth-group barrel 127. Therefore, the impact at the time of collision is large, posing problems in terms of quality, such as drive noise, and drive accuracy.

[0041] Furthermore, it is common for linear ultrasonic motors to use feedback control in which the position of the fourth group barrel, which is the moving part, is detected by a position sensor and control is performed based on the difference between the commanded drive position and the actual position. Note that, although this embodiment describes feedback control performed based on position deviation, control may also be performed based on velocity, acceleration, acceleration deviation, differentiation, or integration, or a combination thereof.

[0042] In this feedback control, if the fourth-group barrel 122 is stationary at a specific position and collides with the fifth-group barrel 127, the retracted state described above is entered. That is, with the fourth-group barrel 122 and the fifth-group barrel 127 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 commanded position (the position that should 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 commanded position and the actual position of the fourth-group barrel 122 becomes large, and 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 further narrow the gap between the fifth group barrel 127, oscillation may occur, potentially generating loud collision noises and drive noises. The following explains how these issues can be resolved and how precision and quality can be improved while still achieving product miniaturization.

[0043] Figure 13 is a diagram showing the region where control by the control means is changed at each position in the diagram of Figure 8. Figure 13 shows the movement trajectories of the fourth-group barrel 122 and the fifth-group barrel 127 relative to 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 and retreat at the position of interference region AR4. The range over which the fourth-group barrel 122 can move by driving the linear ultrasonic motor 124 is range B in Figure 13, and in this embodiment, B is a wider range than the optically necessary range at the telephoto end, providing ample room. The range over which the fifth-group barrel 127 can move is range C in Figure 13 (only the object-side range is shown), and range B over which the fourth-group barrel 122 can move overlaps with range A, resulting in mutual interference.

[0044] In FIG. 13, areas AR1, AR2, AR3, and AR4 respectively represent the optical use area, the interference avoidance area, the near-interference area, and the interference area, which will be described later. These areas are defined relative to the zoom position and the focus position and are stored, for example, as a determination table in the control unit. The optical use area AR1 is the area sandwiched between the L4 infinity line and the L4 closest line in FIG. 13. The interference avoidance area AR2 is the diagonally shaded area sandwiched between the L4 closest line and a solid curve in FIG. 13. The interference area AR4 is the colored area in FIG. 13, and is an area whose image-side end is the image-side end of the movement range of the fourth-group barrel 122 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. 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 for 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 within the zoom variable range where focusing can be achieved at a subject distance (object distance) specified for the product. That is, the optical use area AR1 is an area where the zoom lens group moves to zoom positions from the wide-angle end to the telephoto end, and the focus lens group moves to focus at subject distances from the close-up 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, effective for imaging.

[0046] Feedback control is performed within the optical use area AR1, and settings are made taking into consideration the quality of drive noise during zooming and the positional accuracy of the drive. 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.

[0047] Next, the interference area AR4 will be described. The interference region is the range represented by maximum interference amount A at the wide-angle end in FIG. 8 (FIG. 13), and it is within this range that interference actually occurs between the fourth-group barrel 122 and the fifth-group barrel 127. In other words, the fifth-group barrel 127 restricts the image-side movement limit of the fourth-group barrel 122. Although FIG. 8 (FIG. 13) shows this as a region, the fourth-group barrel 122 is not positioned within this range. In fact, it is positioned on 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. In other words, within the interference region AR4, the fourth-group barrel 122 can only be positioned on curve M. However, at each zoom position within the interference region AR4, the rack 131 can move to its structurally image-side end position by compressing the rack spring 132. This compressed state of the rack spring 132 corresponds to the region of the interference region AR4 closer to the image side than curve M.

[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. Therefore, since feedback control based on the deviation of the actual position from 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 drive speed and acceleration of the fourth-group barrel 122 under feedback control may be controlled to be lower than in regions outside the interference region AR4, or to have a lower maximum speed.

[0049] 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.

[0050] Next, the interference avoidance area AR2 will be described. As mentioned above, in the interference avoidance area AR2, when zooming is performed at high speed, control is performed to avoid entry into the interference area AR4 as much as possible. In other words, even when zooming at high speed, control is performed to avoid collision (interference, contact) between the fourth group barrel 122 and the fifth group barrel 127. In other words, 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 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.

[0052] Finally, the control in the pre-interference region AR3 will be explained. 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 from the interference region AR4.

[0053] The pre-interference region AR3 is a region where control is performed to mitigate the noise generated at the time of collision, the drive noise, and the degradation of the captured image quality that occurs when the fourth group barrel 122 and the fifth group barrel 127 enter the interference region AR4 (curve M) even though control has been performed to minimize interference in the interference avoidance region AR2. That is, the pre-interference region AR3 is in a pre-contact state just before contact between the fourth group barrel 122 and the fifth group barrel 127. The specific control for the pre-interference region AR3 differs depending on whether the entry is 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 pre-interference area AR3 from the interference avoidance area AR2 side, 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, 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.

[0055] On the other hand, if the zoom lens enters from the interference area AR4, 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 side (for example, the optical use area AR1 or the interference avoidance area AR2). If the lens is in this position when the power is turned on, the same as above occurs.

[0056] By performing the above-described control, it is possible to provide a compact lens device that achieves improved drive accuracy, drive noise 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 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 13.

[0058] 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.

[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] 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, move to position P3, return to the optical use area AR1, and reach position Pw.

[0061] Next, the case where even faster zooming is performed will be described. High-speed zooming from the telephoto end position Pt causes the lens to move to position P4, tracing a path with a greater delay than the path described above. From here, the lens enters interference avoidance region AR2, and attempts to avoid collision by increasing the focus speed. However, the drive speed of the movable part 126 (fourth-group barrel 122) cannot keep up, 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 zoom position at the wide-angle end.

[0062] In this state, an interference state occurs, and a drive force is applied to the fourth group barrel 122 to move it to the immediate interference area AR3, causing it to move to position P8, entering the interference avoidance area AR2. It then moves to position P9, entering the optical use area AR1, and either the control parameters for feedback control change, or control switches to feedforward control, resulting in it reaching position Pw, the position that was originally intended for 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 if interference cannot be avoided, to avoid oscillation, reduce drive noise (collision noise) and vibration when they collide, 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 not only on the position but also on the zoom speed (the movement speed of the zoom lens group). For example, if the zoom speed is fast, the just-before-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 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.

[0067] For example, the area may be divided into two, 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 between. 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 just-before-interference area AR3. In other words, in the non-interference area, the fourth group barrel 122 and the fifth group barrel 127 are in a non-contact state. In this case, feedback control is applied to the non-interference area that includes the optical use area AR1, and feedforward control is applied to the side where interference occurs (interference area AR4), thereby preventing the generation of loud drive noises or collision noises due to oscillation during interference.

[0068] Furthermore, the area may be divided into more than four areas, and the area just before interference may be divided into two areas, and the quality may be further improved by 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] In this embodiment, as shown in range A in Fig. 8, an interference region exists on the imaging plane side in the optical axis direction of the electrically driven fourth group barrel 122, but an interference region may also exist on the object side of the electrically driven fourth group barrel 122. Furthermore, an interference region may also exist on both the imaging plane 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 achieved by using a driving means such as a step motor.

[0071] An imaging device that enjoys the effects of the present invention can be realized by an imaging device 300 (Figure 14) that has 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.

[0072] (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. 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 (drive means) 125 Fixed part (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 performing feedback control of the driving means; a first detection means for detecting the 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; The control means determining whether the first and second holding members are in a contact state where they are in contact with each other or in a non-contact state where they are not in contact with each other based on the detection results of the first and second detection means; When the contact state is determined, the feedback control performs one of the following controls: setting an upper limit value for the input deviation; driving the lens at a lower speed than when the non-contact state is determined; or driving the lens at a lower acceleration than when the non-contact state is determined.

2. A first holding member that holds a first lens group that moves 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 the 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; The control means determining whether the first and second holding members are in a contact state where they are in contact with each other or in a non-contact state where they are not in contact with each other based on the detection results of the first and second detection means; The lens device is characterized in that the driving means is controlled by feedforward control when the contact state is determined, and by feedback control when the non-contact state is determined.

3. A first holding member that holds a first lens group that moves 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 the 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; The control means changes the control of the drive means based on a judgment table that defines two or more states for the positions of the first and second holding members, including a contact state in which the first and second holding members are in contact with each other and a non-contact state in which they are not in contact with each other, and on the detection results of the first and second detection means.

4. A first holding member that holds a first lens group that moves 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 the 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; The control means determining, based on the detection results of the first and second detection means, whether the first and second holding members are in an imaging effective state effective for imaging, a contact avoidance state in which the first and second holding members avoid contact with each other, or a contact state in which the first and second holding members contact each other; The lens device is characterized in that the control of the driving means is changed based on the result of the judgment.

5. 5. The lens device according to claim 4, wherein the control means determines whether the lens is in the contact avoidance state or a pre-contact state where the first and second holding members are about to come into contact with each other based on the detection results of the first and second detection means, and changes the control of the drive means based on the result of the determination.

6. The lens device described in Claim 5, characterized in that the control means determines whether the contact avoidance state has changed to the just-before-contact state or the contact state has changed to the just-before-contact state based on the detection results of the first and second detection means, and changes the control of the drive means based on the result of the determination.

7. 7. The lens device according to claim 6, wherein the boundary between the contact avoidance state and the immediately-contact state changes based on the moving speed of the first holding member based on the detection result of the first detection means.

8. A lens device as described in Claim 6 or 7, characterized in that when the control means determines that the contact avoidance state is in effect, it changes the control of the drive means so as to increase the acceleration or maximum speed of the second holding member compared to when it determines that the imaging effective state is in effect.

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

10. A method for controlling a lens apparatus by the control means in the lens apparatus according to any one of claims 1 to 8.

11. A program that causes a processor to execute the control method for a lens device described in claim 10.

Images