Optical equipment

Abstract

The present invention provides a compact optical device having multiple driving means for driving multiple lens groups. [Solution] The optical device includes first and second holding members 104 and 106 that each hold first and second optical elements L4 and L6, first and second guide members 153 and 155 that guide the movement of the first and second holding members in the optical axis direction, and first and second driving means 151 and 152 that drive the first and second holding members. When viewed in the optical axis direction, the first region is divided into three circumferential regions AR1 to AR3, with the optical axis at the center. The first driving means and the first guide means are located in the first region, the second driving means and the third guide means are located in the second region, and a rotation stopper is located in the third region. The first driving means is located closer to the rotation stopper than the first guide member, and the second driving means is located closer to the rotation stopper than the second guide member.

Description

Technical Field

[0001] The present invention relates to an optical device that moves a plurality of lens groups to perform zooming, focusing, etc.

Background Art

[0002] In order to shorten the shortest imaging distance or improve the image quality in closest imaging, it may be necessary to move a plurality of lens groups during focusing. Patent Document 1 discloses an optical device in which a plurality of driving means (actuators) for moving each of a plurality of lens groups are arranged on a straight line parallel to the optical axis. Patent Document 2 discloses an optical device in which a plurality of actuators for moving each of a plurality of lens groups are arranged on the same circle centered on the optical axis in a plane orthogonal to the optical axis.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a plurality of actuators are arranged side by side in the optical axis direction as in Patent Document 1, when the lens groups are separated from each other in the optical axis direction, the actuators also need to be separated in the optical axis direction, which hinders miniaturization of the optical device. Also, when a plurality of actuators are arranged in the circumferential direction as in Patent Document 2, it becomes difficult to secure a phase region for holding a fixed lens group when arranging another fixed lens group between the lens groups driven by these actuators.

[0005] The present invention provides a small optical device having a plurality of actuators (driving means) for driving a plurality of lens groups. [Means for solving the problem]

[0006] An optical device as one aspect of the present invention includes a first guide member for guiding the movement of a first holding member that holds a first optical element in the optical axis direction, a second guide member for guiding the movement of a second holding member that holds a second optical element in the optical axis direction, a rotation-stopping member for preventing the rotation of the first and second holding members, a first driving means for moving the first holding member, a second driving means for moving the second holding member, and a base member for holding the first and second driving means, and when viewed from the optical axis direction... The axis passing through the optical axis and the holding portions for holding the base member, which are provided at three locations in the circumferential direction, is defined as the first axis, the second axis, and the third axis, respectively. The area between the first and second axes is defined as the first region, the area between the first and third axes is defined as the second region, and the area between the second and third axes is defined as the third region. The first driving means and the first guide member are arranged in the first region, the second driving means and the second guide member are arranged in the second region, and the rotation-preventing member is arranged in the third region. [Effects of the Invention]

[0007] According to the present invention, it is possible to miniaturize an optical device having multiple driving means for driving multiple optical elements. [Brief explanation of the drawing]

[0008] [Figure 1] A cross-sectional view of the replacement lens of Example 1, as seen from the optical axis direction. [Figure 2] Cross-sectional view of the interchangeable lens of Example 1 at the wide-angle end. [Figure 3] Cross-sectional view of the interchangeable lens of Example 1 at its telephoto end. [Figure 4] Exploded perspective view of the replacement lens of Example 1. [Figure 5] A view of the replacement lens of Example 1 from the direction of the first axis. [Figure 6] A cross-sectional view of the replacement lens of Example 2, as seen from the optical axis direction. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Examples]

[0010] Figures 2 and 3 show the configuration of an interchangeable lens 100 as an optical device (lens device) according to Embodiment 1 of the present invention. Figure 2 shows a cross-section of the interchangeable lens 100 at the wide-angle end when cut parallel to the optical axis, and Figure 3 shows a cross-section of the interchangeable lens 100 at the telephoto end when cut parallel to the optical axis. The interchangeable lens 100 in this embodiment is detachably attached to a camera body, which is an imaging device (not shown) equipped with an image sensor such as a CCD sensor or a CMOS sensor.

[0011] The interchangeable lens 100 has an imaging optical system composed of first to seventh lens groups L1 to L7 arranged in order from the subject side (front side). The imaging optical system forms an image of the subject on the image sensor inside the camera body by imaging light from a subject (not shown). Focusing is performed by the movement of the fourth lens group L4, which is a floating lens group, and the sixth lens group L6, which is a focusing lens group, along the optical axis, and zooming is performed by the movement of the first to seventh lens groups L1 to L7 along the optical axis. In this embodiment, an interchangeable lens is described, but the optical device may be an integrated lens imaging device.

[0012] The lens mount 111 has a bayonet section for detachable attachment to the camera body and is fixed to the rear fixing cylinder 112 via an outer cylinder 113 with screws. The outer cylinder 113 is sandwiched and fixed between the lens mount 111 and the rear fixing cylinder 112. The front fixing cylinder 115 is fixed to the rear fixing cylinder 112 with screws. A zoom indicator and operation switches (not shown) are attached to the front fixing cylinder 115. The guide cylinder 116 is fixed to the rear fixing cylinder 112 with screws.

[0013] The guide tube 116 has straight grooves that guide each lens group in the direction of the optical axis. The guide tube 116 is also provided with cam grooves, and a cam follower (not shown), fixed to the cam tube 117 with screws, engages with these cam grooves. As a result, the cam tube 117 rotates around the optical axis while moving (straight) in the direction of the optical axis during zooming. The cam tube 117 has multiple cam grooves that allow each lens group that moves during zooming to move straight.

[0014] The zoom operating cylinder 118 is held rotatably around the optical axis by diameter-fitting with the guide cylinder 116 and bayonet engagement. The rotation of the zoom operating cylinder 118 by the user's zoom operation causes the straight-line cylinder 122 to move in a straight line due to the straight-line guiding action of the cam groove formed in the zoom operating cylinder 118, the cam follower provided on the outside of the straight-line cylinder 122, and the straight-line groove of the guide cylinder 116. The cam follower of the straight-line cylinder 122 also engages with the cam groove of the cam cylinder 117, so that when the straight-line cylinder 122 moves in a straight line, the cam cylinder 117 rotates around the optical axis. At this time, the cam cylinder 117, which is rotatable and can move in a straight line relative to the guide cylinder 116, moves in a straight line while rotating due to the straight-line movement of the straight-line cylinder 122.

[0015] As the cam cylinder 117 rotates and moves in a straight line relative to the guide cylinder 116, the rear group rollers 123, which are provided at three circumferential locations around the optical axis in the rear group unit (described later), and the seven group rollers 124, which are provided at three circumferential locations around the seven group unit (described later), engage with the straight-line groove of the guide cylinder 116 and the cam groove of the cam cylinder 117, causing the rear group unit and the seven group unit to be driven separately in the optical axis direction.

[0016] Thus, in the interchangeable lens 100 of this embodiment, the rotation of the zoom operating barrel 118 causes the straight-line barrel 122 to move in a straight line (the first lens group L1 fixed to the straight-line barrel 122 moves in the optical axis direction as described later), and the rotation and straight-line movement of the cam barrel 117 causes the second to seventh lens groups L2 to L7 to move in the optical axis direction.

[0017] The first lens holding frame 101 holds the first lens group L1 and is fixed to the straight barrel 122 with screws. The first lens pressing ring 125 has an internal thread formed on its inner peripheral portion and is fixed by screwing with an external thread formed on the outer peripheral portion of the straight barrel 122. The first lens pressing ring 125 has a role of fixing the first lens group L1.

[0018] Bayonet claws for hood attachment are formed on the outer peripheral portion of the straight barrel 122, and screws for attaching accessories such as filters are formed on the inner peripheral portion.

[0019] The second lens holding frame 102 holds the second lens group L2 and forms part of the anti-shake unit 108. The anti-shake unit 108 holds the second lens holding frame 102 movably in a direction perpendicular to the optical axis (hereinafter referred to as the shift direction), and reduces image blur by driving the second lens holding frame 102 in the shift direction by a shift actuator composed of a magnet and a coil. The anti-shake unit 108 is held in a manner of being suspended from the guide cylinder 116 via rollers.

[0020] The third lens holding frame 103 holds the third lens group L3 and is held by the rear group base 126 via three cam followers (129 in FIG. 5) arranged at three circumferential positions of the third lens holding frame 103. The third lens holding frame 103 moves in the optical axis direction when the rear group base 126 moves straight during zooming. The third lens holding frame 103 also holds an electromagnetic diaphragm unit 110 composed of a plurality of diaphragm blades and a diaphragm actuator for driving the opening and closing of these blades.

[0021] The fourth lens holding frame 104, as the first holding member, holds the fourth lens group L4, as the first optical element, and is guided in a straight line by a guide bar 153, as the first guide member, whose front and rear ends are held by the rear group base 126 and the first rear group cover 127 fixed to the rear group base 126. The fourth lens group L4 (fourth lens holding frame 104) moves in the same direction as the rear group base 126 moves in the optical axis direction during zooming, and also moves when driven in the optical axis direction by the fourth lens drive motor unit 151, as the first driving means, relative to the rear group base 126.

[0022] The fourth lens retaining frame 104 is equipped with a scale for detecting its position in the optical axis direction. An optical sensor opposite the scale is fixed to the rear group base 126 via a flexible printed circuit board (FPC). The scale and the optical sensor constitute the position detection means.

[0023] The fifth lens retaining frame 105, acting as a third retaining member, holds the fifth lens group L5, which acts as a third optical element, and is held by the rear group base 126 via three cam followers (retaining parts) 159 fixed at three locations in the circumferential direction of the fifth lens retaining frame 105. The fifth lens retaining frame 105 moves in the optical axis direction as the rear group base 126 moves in a straight line during zooming.

[0024] The sixth lens retaining frame 106, which serves as a second retaining member, holds the sixth lens group L6, which serves as a second optical element, and is guided in a straight line by a guide bar 155, which serves as a second guide member, with its front and rear ends held by the rear group base 126 and the first rear group cover 127.

[0025] The motor unit drive base 135 is mounted to the rear group base 126 so as to be movable in the optical axis direction and is bayonet-engaged with the 7-group base 109 so as to be integrated only in the optical axis direction. The biasing force of the 7-group spring 136 attached to the 7-group base 109 eliminates the play in the optical axis direction between the 7-group base 109 and the motor unit drive base 135.

[0026] The sixth lens retaining frame 106 is driven in the optical axis direction relative to the motor unit drive base 135 by the sixth lens drive motor unit 152, which serves as a second driving means.

[0027] The seventh lens retaining frame 107 holds the seventh lens group L7 and is screwed and fixed to the seventh group base 109. During zooming, the seventh lens retaining frame 107 is driven in the optical axis direction together with the seventh group base 109 by three cam followers provided on the seventh group base 109. The seventh group unit is formed by the seventh group base 109 and the seventh lens retaining frame 107.

[0028] In this embodiment, the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152 are vibration-type linear motors using piezoelectric elements. The vibration-type linear motor consists of a motor stator 130, a motor movable element 131 which moves in the optical axis direction relative to the motor stator 130 when vibration is excited by the piezoelectric element, and a motor output section which moves in the optical axis direction together with the motor movable element 131. The motor stators 130 of the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152 are fixed to a motor unit drive base 135. The motor unit drive base 135, together with the rear group base 126, constitutes a base member that holds the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152.

[0029] As shown in Figure 1 and Figure 4 (which shows the rear group unit disassembled), the motor output sections of the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152 are engaged with arms 132, which are drive transmission members that transmit the driving force from the motor output sections to the fourth lens retaining frame 104 or the sixth lens retaining frame 106. This enables the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152 to drive the fourth lens retaining member 104 and the sixth lens retaining member 106 in the optical axis direction. However, Figures 1 and 4 only show the arms 132 provided for the sixth lens retaining frame 106.

[0030] Furthermore, stepping motors may be used as the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152, and the arms may be engaged with lead screws provided at the motor output section. When using stepping motors, it is also possible to eliminate the position detection means and perform open drive control.

[0031] The zoom operating cylinder 118 is provided with a groove for holding the movable element of a resistive linear sensor (potentiometer) 134, which is a zoom position detection means (not shown) fixed to the guide cylinder 116. The zoom position can be detected by changing the output of the resistive linear sensor 134 in accordance with the amount of rotation of the zoom operating cylinder 118.

[0032] The focus control cylinder 114 is held between the front fixing cylinder 115 and the rear fixing cylinder 112 so that it can rotate at a fixed position in the optical axis direction on the outer circumference of the front fixing cylinder 115. The amount and direction of rotation of the focus control cylinder 114 are detected by a photodetector provided on the front fixing cylinder 115 and a brightness scale provided on the inner circumference of the focus control cylinder 114 opposite the photodetector.

[0033] The multi-purpose operating cylinder 121 is held between the rear fixing cylinder 112 and the outer cylinder 113 so that it can rotate at a fixed position in the optical axis direction on the outer circumference of the rear fixing cylinder 112. The amount and direction of rotation of the multi-purpose operating cylinder 121 are detected by a photodetector provided on the rear fixing cylinder 112 and a brightness scale provided on the inner circumference of the multi-purpose operating cylinder 121 opposite the photodetector. The multi-purpose operating cylinder 121 and the rear fixing cylinder 112 also have a click mechanism consisting of a plurality of grooves that provide a click sensation to user operation, and a click pin biased by a spring in the grooves.

[0034] The lens control unit (control board) 119, acting as a control means, controls the entire operation of the interchangeable lens 100, including focus drive control, aperture drive control, and image stabilization control. When zooming occurs, the lens control unit 119 controls the movement of the fourth lens group L4 and the sixth lens group L6 (i.e., the driving of the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152) so that the focus position and various aberrations that fluctuate due to the zooming are kept below a certain value. The lens control unit 119 is fixed to the rear fixing cylinder 112 by screws.

[0035] Next, we will describe the more detailed configuration of the rear group unit using Figures 1, 4, and 5. Figure 1 shows the rear group unit as viewed from the optical axis direction (front side), and Figure 4 shows the rear group unit as disassembled as described above. Figure 5 shows the rear group unit as viewed from the direction of the first axis, which will be described later.

[0036] The rear group base 126, which moves in a straight line during zooming, holds the third to sixth lens groups L3 to L6. However, Figure 4 only shows the fourth to sixth lens groups L4 to L6.

[0037] As described above, the fourth lens group L4 held by the fourth lens holding frame 104 is a floating group and is driven in the optical axis direction by the fourth lens drive motor unit 151. The sleeve portion 104a of the fourth lens holding frame 104 is engaged (fitted) with the guide bar 153 at two locations, front and rear, so as to be movable in the optical axis direction, thereby preventing the fourth lens holding frame 104 from tilting relative to the optical axis and from being positioned perpendicular to the optical axis. In addition, the U-groove portion 104b of the fourth lens holding frame 104 is engaged with the rotation stopper bar 154, which acts as the first rotation stopper member, so as to be movable in the optical axis direction. The front end of the rotation stopper bar 154 is held by the rear group base 126, and the rear end is held by the second rear group cover 128 fixed to the rear group base 126.

[0038] The aforementioned arm 132, which is rotatably mounted on the fourth lens holding frame 104, is engaged with the motor output section of the fourth lens drive motor unit 151 by the biasing force of the arm biasing spring (biasing means) 133, which is a torsion coil spring arranged around its rotational axis. This eliminates the engagement play of the arm 132 with respect to the motor output section. The biasing force of the arm biasing spring 133 also biases the fourth lens holding frame 104 in a direction that causes it to rotate around the guide bar 153, causing the groove 104b to come into contact with the rotation stopper bar 154. This eliminates the rotation play of the fourth lens holding frame 104.

[0039] The position of the fourth lens retaining frame 104 in the optical axis direction relative to the rear group base 126 is detected by reading a scale (not shown) fixed to the fourth lens retaining frame 104 using a fourth lens position sensor 157, which is a first position detection means fixed to the rear group base 126.

[0040] As described above, the fifth lens retaining frame 105 is held by the rear group base 126 via three cam followers 159 fixed to follower mounting portions 105a provided at three locations in its circumferential direction.

[0041] As mentioned above, the sixth lens group L6 held by the sixth lens holding frame 106 is the focusing group and is driven in the optical axis direction by the sixth lens drive motor unit 152. The sleeve portion 106a of the sixth lens holding frame 106 is engaged (fitted) with the guide bar 155 at two locations, front and rear, so as to be movable in the optical axis direction, thereby preventing the sixth lens holding frame 106 from tilting relative to the optical axis and from being positioned perpendicular to the optical axis. In addition, the U-groove portion 106b of the sixth lens holding frame 106 is engaged with the rotation stopper bar 156, which serves as a second rotation stopper member, so as to be movable in the optical axis direction. The front end of the rotation stopper bar 156 is held by the rear group base 126, and the rear end is held by the second rear group cover 128.

[0042] The aforementioned arm 132, which is rotatably mounted on the sixth lens holding frame 106, is engaged with the motor output of the sixth lens drive motor unit 152 by the biasing force of a torsion arm biasing spring 133 positioned around its rotational axis. This eliminates the engagement play of the arm 132 with respect to the motor output. The biasing force of the arm biasing spring 133 also biases the sixth lens holding frame 106 in a direction that causes it to rotate around the guide bar 155, causing the U-groove portion 106b to come into contact with the rotation stopper bar 156. This eliminates the rotation play of the sixth lens holding frame 106.

[0043] The position of the sixth lens holding frame 106 in the optical axis direction relative to the rear group base 126 is determined by the position of the motor unit drive base 135 relative to the rear group base 126 and the position of the motor movable element 131 of the sixth lens drive motor unit 152 in the optical axis direction relative to the motor unit drive base 135. The position of the sixth lens holding frame 106 in the optical axis direction relative to the rear group base 126 is detected by reading a scale (not shown) fixed to the sixth lens holding frame 106 using a sixth lens position sensor 158, which is a second position detection means fixed to the rear group base 126.

[0044] In this embodiment, the fourth lens group L4 is a floating group and the sixth lens group L6 is a focusing group, and the case where these lens groups move during focusing is described. However, one lens group may move for zooming and the other lens group may move for focusing. Also, in this embodiment, the case where the sixth lens group L6 moves relative to the motor unit drive base 135 is described, but the motor unit drive base 135 may be omitted.

[0045] Next, the arrangement of the components constituting the rear group unit will be explained using Figure 1. The first axis A1, the second axis A2, and the third axis A3 shown in Figure 1 are straight lines that pass through the position of the optical axis AX and through the centers of the three cam followers 159 that hold the fifth lens retaining frame 105 to the rear group base 126. The three cam followers 159 are arranged at approximately 120-degree intervals in the circumferential direction, and therefore the angles between adjacent axes in the circumferential direction of the first to third axes A1, A2, and A3 are also approximately 120 degrees.

[0046] In this embodiment, the phases of the three cam followers 159 for holding the fifth lens retaining frame 105 on the rear group base 126 and the three rear group rollers (retaining parts) 123 for holding the rear group base 126 (i.e., the rear group unit) on the guide tube (other member) 116 are arranged in the same phase. Therefore, in a view along the optical axis, the first axis A1, the second axis A2, and the third axis A3 are also straight lines that pass through the optical axis AX and the centers of the three rear group rollers 123.

[0047] Furthermore, in the circumferential direction, the region between the first and second axes A1 and A2 is defined as the first region AR1, and the region between the first and third axes A1 and A3 is defined as the second region AR2. In addition, the region between the second and third axes A2 and A3 is defined as the third region AR3.

[0048] The first region AR1 includes a fourth lens drive motor unit 151, an arm 132 provided on the fourth lens holding frame 104, an arm biasing spring 133 that biases the arm, and a guide bar 153 that guides the fourth lens holding frame 104. The guide bar 153 is positioned further from the first axis A1 than the fourth lens drive motor unit 151. Furthermore, in the first region AR1, a rotation stopper bar 156 that prevents the rotation of the sixth lens holding frame 106 is positioned close to the guide bar 153 (i.e., further from the first axis A1 than the fourth lens drive motor unit 151).

[0049] In the second region AR2, the sixth lens drive motor unit 152, a rack 132 provided on the sixth lens holding frame 106, an arm biasing spring 133 that biases the rack, and a guide bar 155 that guides the sixth lens holding frame 106 are arranged. The guide bar 155 is positioned further from the first axis A1 than the sixth lens drive motor unit 152. Furthermore, in the second region AR2, a rotation stopper bar 154 that prevents the rotation of the fourth lens holding frame 104 is positioned close to the guide bar 155 (i.e., further from the first axis A1 than the sixth lens drive motor unit 152).

[0050] In this embodiment, the fourth and sixth lens groups L4 and L6, driven by the fourth and sixth lens drive motor units 151 and 152 respectively, are in close proximity to each other in the optical axis direction, although the fifth lens group L5 is sandwiched between them. In such a lens group arrangement, by arranging the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152 in a first region AR1 and a second region AR2, which are mutually different regions in the circumferential direction, as described above, the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152 can be arranged in two regions where at least a portion of the optical axis direction overlaps, as shown in Figures 1 and 5. This makes it possible to miniaturize the rear group unit (i.e., the interchangeable lens 100) in the optical axis direction compared to the case where the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152 are arranged in two regions that do not overlap at all in the optical axis direction.

[0051] Furthermore, by arranging the lens drive motor unit and related components (arm 132, arm biasing spring 133, and guide bars 153, 155) in the first region AR1 and the second region AR2 respectively, it becomes possible to position the follower mounting portion 105a, to which the cam follower 159 for holding the fifth lens holding frame 105 is attached, near the boundary of each region, thereby securing the follower mounting portion 105a without increasing the size of the interchangeable lens 100.

[0052] As described above, according to this embodiment, the interchangeable lens 100 having fourth and sixth lens drive motor units 151 and 152 that drive the fourth and sixth lens groups L4 and L6 can be miniaturized.

[0053] Furthermore, in this embodiment, the fourth lens drive motor unit 151 and its related components, and the sixth lens drive motor unit 152 and its related components are arranged symmetrically with respect to the first axis A1. Symmetrical arrangement here includes not only perfectly symmetrical arrangements, but also arrangements that can be considered approximately symmetrical. Figure 1 shows the moment M1 generated in the fourth lens holding frame 104 by the biasing force of the arm biasing spring 133 that biases the arm 132 provided on the fourth lens holding frame 104, and the moment M2 generated in the sixth lens holding frame 106 by the biasing force of the arm biasing spring 133 that biases the arm 132 provided on the sixth lens holding frame 106. Also shown are the reaction force F1 received by the U-groove portion 104b of the fourth lens holding frame 104 due to moment M1, and the reaction force F2 received by the U-groove portion 106b of the sixth lens holding frame 106 due to moment M6.

[0054] The direction of reaction force F1 is perpendicular to the line connecting the guide bar 153 and the U-groove 104b of the fourth lens retaining frame 104, and the direction of reaction force F2 is perpendicular to the line connecting the guide bar 155 and the U-groove 106b of the sixth lens retaining frame 106. Therefore, by arranging the arms 132 and arm biasing springs 133, as well as the U-grooves 104b and 106b, associated with the fourth and sixth lens retaining frames 104, 104 respectively, symmetrically with respect to the first axis A1, the reaction forces F1 and F2 can be made to point in the same direction. The same direction here is not limited to perfectly identical (parallel) directions, but may also be non-parallel directions that can be considered to be approximately the same direction.

[0055] If the biasing force of the arm biasing spring 133 is less than the weight of the lens group and the lens retaining frame, play will occur in the retention of the lens retaining frame. However, since the reaction forces F1 and F2 are directed in the same direction, it is not necessary to generate a strong biasing force on only one of the arm biasing springs 133. Therefore, it is not necessary to use a larger spring or to thicken the guide bar to ensure strength against the large load generated by the strong biasing force, and the interchangeable lens 100 can be made smaller. In addition, it is possible to avoid a large frictional force between the guide bar and the lens retaining frame (sleeve portion and U-groove portion) due to a large load, and it is not necessary to increase the driving force or enlarge the lens drive motor unit, so the interchangeable lens 100 can be made more power-efficient and smaller.

[0056] To align the directions of the reaction forces F1 and F2, it is preferable to bring the guide bar 153 for the fourth lens retaining frame 104 and the rotation-retaining bar 156 for the sixth lens retaining frame 106 closer together, and to bring the guide bar 155 for the sixth lens retaining frame 106 and the rotation-retaining bar 154 for the fourth lens retaining frame 104 closer together. Furthermore, it is even more preferable to share one guide bar as the guide bar 153 for the fourth lens retaining frame 104 and the rotation-retaining bar 156 for the sixth lens retaining frame 106, and to share the other guide bar as the guide bar 155 for the sixth lens retaining frame 106 and the rotation-retaining bar 154 for the fourth lens retaining frame 104.

[0057] Furthermore, in this embodiment, the flexible printed circuit board 160, which serves as a first connecting member connecting the fourth and sixth lens drive motor units 151 and 152 to the lens control unit 119, is arranged to extend in the optical axis direction near the first axis A1. Specifically, as shown in Figures 1 and 5, the connecting portion 151b of the fourth lens drive motor unit 151 and the connecting portion 152b of the sixth lens drive motor unit 152 extend circumferentially toward the flexible printed circuit board 160 located on the first axis A1 side and are connected to the flexible printed circuit board 160.

[0058] To enable such connections, this embodiment uses motor units with the same configuration as the fourth lens drive motor unit 151 and the sixth lens drive motor unit 152, and arranges them with their front and back reversed. This eliminates the need to use separate motor units for the fourth and sixth lens drive motor units 151 and 152. Furthermore, since the fourth and sixth lens drive motor units 151 and 152 and the lens control unit 119 can be connected on a single flexible printed circuit board 160, the space required for connection can be reduced, and the interchangeable lens 100 can be miniaturized.

[0059] In this embodiment, the flexible printed circuit board 161, which serves as a second connecting member for connecting the fourth lens position sensor 157 and the sixth lens position sensor 158 to the lens control unit 119, is located in the third region AR3, which is the phase region opposite to the first axis A1 in Figure 1. Compared to the first and second regions AR1 and AR2, where the fourth and sixth lens drive motor units 151 and 152 are located, the third region AR3 has more space. By placing the flexible printed circuit board 161 in the third region AR3, which is different from the first and second regions AR1 and AR2, a more natural arrangement becomes possible. Moreover, since the connection of the fourth and sixth lens position sensors 157 and 158 can be done with a single flexible printed circuit board 161, the space required for connection can be reduced, and the interchangeable lens 100 can be miniaturized.

[0060] Furthermore, the first to third axes A1, A2, and A3 do not necessarily have to be straight lines passing through the centers of the three cam followers 159 in order to hold the fifth lens group L5. For example, in this embodiment, the three cam followers 159 and the three rear group rollers 123 are arranged in the same phase, but the three rear group rollers 123 may be arranged in a different phase from the three cam followers 159, and the axes passing through the centers of the three rear group rollers 123 may be used as the first to third axes. In addition, instead of holding by cam followers, holding using fixing members such as screws may also be used.

[0061] As a variation of the above embodiment, the connection portions 151b and 152b of the fourth and sixth lens drive motor units 151 and 152 may be extended in the circumferential direction toward the side opposite to the first axis A1. In this case, the connection portion 151b of the fourth lens drive motor unit 151 and the fourth lens position sensor 157 are connected to a flexible printed circuit board, which is then connected to the lens control unit 119. The connection portion 152b of the sixth lens drive motor unit 152 and the sixth lens position sensor 158 are connected to a separate flexible printed circuit board, which is then connected to the lens control unit 119. However, considering the influence of noise generated by the driving of the fourth and sixth lens drive motor units 151 and 152 on the signals from the fourth and sixth lens position sensors 157 and 158, the connections in the above embodiment are preferred. [Examples]

[0062] Figure 6 shows a cross-section of an interchangeable lens, which is Embodiment 2 of the present invention, as viewed from the optical axis direction. Components of the interchangeable lens in this embodiment that are common with Embodiment 1 are denoted by reference numerals in the 200s, with the same last two digits as the reference numerals in the 100s in Embodiment 1. The first axis A21, the second axis A22, and the third axis A23 shown in Figure 6 are straight lines that pass through the optical axis AX and through the centers of three cam followers 259 that hold the fifth lens group, which is positioned between the fourth and sixth lens groups, to the rear group base 226. The three cam followers 259 are arranged at approximately 120-degree intervals in the circumferential direction, and therefore the angles between adjacent axes in the circumferential direction of the first to third axes A21, A22, and A23 are also approximately 120 degrees. In the circumferential direction, the region between the first and second axes A21 and A22 is defined as the first region AR21, and the region between the first and third axes A21 and A23 is defined as the second region AR22. Furthermore, the region between the second and third axes A22 and A23 is defined as the third region AR23.

[0063] In this embodiment, the arrangement of the fourth and sixth lens drive motor units and the guide bars is reversed compared to Embodiment 1. Specifically, in Embodiment 1, the guide bars 153 and 155 are positioned further from the first axis A1 than the fourth and sixth lens drive motor units 151 and 152 in the first and second regions AR1 and AR2, respectively. In contrast, in this embodiment, the fourth and sixth lens drive motor units 251 and 252 are positioned in the first and second regions AR21 and AR22, and the guide bars 253 and 255 are positioned closer to the first axis A21 than the fourth and sixth lens drive motor units 251 and 252 in the first and second regions AR21 and AR22. Furthermore, the fourth lens position sensor 257 and the sixth lens position sensor 258 are also positioned near the first axis A21 in accordance with the arrangement of the guide bars 253 and 255.

[0064] The front ends of the guide bars 253 and 254 that guide the fourth lens retaining frame 204 are held by the rear group base 226, and the rear ends are held by a rear group cover (not shown) fixed to the rear group base 226. The sleeve portion 204a of the fourth lens retaining frame 204 engages with the guide bar 253, and the U-groove portion 204b engages with the rotation-preventing bar 254 located in the third region AR23.

[0065] On the other hand, the front end of the guide bar 255 that guides the sixth lens retaining frame 206 is held by the rear group base 226, and the rear end is held by the rear group cover. The sleeve portion 206a of the sixth lens retaining frame 206 engages with the guide bar 255, and the U-groove portion 206b engages with the anti-rotation bar 254, just like the U-groove portion 204b of the fourth lens retaining frame 204. In other words, in this embodiment, the anti-rotation bar 254, which is the same member (single member), is used as both the first anti-rotation member and the second anti-rotation member.

[0066] Furthermore, similar to Embodiment 1, the first region AR21 is equipped with an arm that engages with the motor movable part of the fourth lens drive motor unit 251 and an arm biasing spring that biases it. The second region AR22 is equipped with an arm that engages with the motor movable part of the sixth lens drive motor unit 252 and an arm biasing spring that biases it.

[0067] By arranging the lens drive motor unit and related components (arm, arm biasing spring, and guide bars 253, 255) in the first region AR21 and the second region AR22 respectively, it becomes possible to position the follower mounting section a, to which the cam follower 259 for holding the fifth lens holding frame 205 is attached, near the boundary of each region, thereby securing the follower mounting section without increasing the size of the interchangeable lens.

[0068] In this embodiment as well, interchangeable lenses having fourth and sixth lens drive motor units 251 and 252 that drive the fourth and sixth lens groups can be miniaturized.

[0069] In this embodiment, it is desirable to place the flexible printed circuit board 261 connecting the fourth lens position sensor 257, the sixth lens position sensor 258, and the lens control unit (not shown) near the first axis A21. It is also desirable to place the flexible printed circuit board 260 connecting the fourth and sixth drive motor units 251 and 252 to the lens control unit in the third region AR23, which is the phase region opposite to the first axis A21. This allows for a space-saving arrangement.

[0070] Furthermore, although the above embodiments have described cases in which each motor unit drives a lens as an optical element, it is also possible to drive optical elements other than lenses, such as an aperture.

[0071] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of Symbols]

[0072] 104 Fourth lens retaining frame 105 Fifth lens retaining frame 106. Lens retaining frame #6 126 Rear group base 153, 154, 155, 156 Guide bars 151 Fourth lens drive motor unit 152. 6th Lens Drive Motor Unit 119 Lens control unit A1 First axis A2 Second axis A3 The third axis AR1 First Domain AR2 Second Domain AR3 Third Domain

Claims

1. A first guide member that guides the movement of a first holding member that holds a first optical element in the optical axis direction, A second guide member that guides the movement of a second holding member that holds a second optical element in the optical axis direction, Rotation-preventing members for preventing the rotation of the first and second holding members, A first driving means for moving the first holding member, A second driving means for moving the second holding member, It has a base member that holds the first and second drive means, When viewed from the direction of the optical axis, the axes passing through the holding parts for holding the base member, which are provided at three locations in the circumferential direction, and the optical axis are designated as the first axis, the second axis, and the third axis, respectively. When the area between the first and second axes is designated as the first region, the area between the first and third axes is designated as the second region, and the area between the second and third axes is designated as the third region, An optical device characterized in that the first driving means and the first guide member are arranged in the first region, the second driving means and the second guide member are arranged in the second region, and the rotation-preventing member is arranged in the third region.

2. The optical device according to claim 1, characterized in that it is detachable from an imaging device.

3. The optical device according to claim 1, characterized by having an image sensor.

Images