Optical device and imaging apparatus including the same

Abstract

To provide an optical device advantageous in terms of miniaturization.SOLUTION: In an interchangeable lens 100 including first to third holding members 104 to 106, first to third guide means 151 to 153, a plurality of driving means, and a rear group base 126, each of the first to third guide means 151 to 153 comprises a pair of guide members including one member and the other member, in the rear group base 126, rear group cam followers 123A to 123C are provided at three places in a circumferential direction, and when axes passing through an optical axis O and the respective rear group cam followers 123A to 123C are set as first to third axes AX1 to AX3 respectively, a first main shaft 151A and a second sub shaft 152B are arranged in a first area AR1 between the first axis AX1 and the second axis AX2, a second main shaft 152A and a third sub shaft 153B are arranged in a second area AR2 between the second axis AX2 and the third axis AX3, and a third main shaft 153A and a first sub shaft 151B are arranged in a third area AR3 between the third axis AX3 and the first axis AX1.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an optical device and an imaging device having the same. [Background technology]

[0002] 2. Description of the Related Art Techniques for moving a plurality of lens groups during focus adjustment are known in order to shorten the minimum shooting distance or improve image quality at close range.

[0003] Patent Document 1 discloses an optical device having a configuration in which two lens groups are moved by separate driving means. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-067719 Summary of the Invention [Problem to be solved by the invention]

[0005] The optical device disclosed in Patent Document 1 achieves compactness in a configuration having two lens groups. However, there is no disclosure of an optical device having three or more moving groups, and in a configuration having three or more moving groups, it is necessary to consider the impact resistance and compactness of each moving group.

[0006] An object of the present invention is to provide an optical device that is advantageous in terms of miniaturization. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides an optical device having a first holding member for holding a first optical element, a second holding member for holding a second optical element, a third holding member for holding a third optical element, a first guide means for guiding movement of the first holding member, a second guide means for guiding movement of the second holding member, a third guide means for guiding movement of the third holding member, a plurality of drive means, and a base member for holding the plurality of drive means, wherein the first, second and third guide means are each constituted by a pair of guide members including one member and the other member, and the base member has a front The base member has three engagement portions provided in a circumferential direction centered on the optical axis, and when axes passing through the optical axis and each of the engagement portions are designated as first, second and third axes, respectively, one member of the first guide means and the other member of the second guide means are arranged in a first region between the first axis and the second axis, one member of the second guide means and the other member of the third guide means are arranged in a second region between the second axis and the third axis, and one member of the third guide means and the other member of the first guide means are arranged in a third region between the third axis and the first axis. Effect of the Invention

[0008] According to the present invention, it is possible to provide an optical device which is advantageous in terms of miniaturization. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of the wide-angle end (wide end) of the interchangeable lens 100 in Example 1. FIG. [Diagram 2] FIG. 2 is an exploded perspective view of a main part according to the first embodiment. [Diagram 3] FIG. 2 is a cross-sectional view of a main part in the first embodiment. [Figure 4] FIG. 11 is a cross-sectional view of a main part in the second embodiment. [Diagram 5] FIG. 11 is a cross-sectional view of a main part in a third embodiment. [Figure 6] FIG. 1 is a schematic diagram showing a configuration example of an imaging device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Example 1 The configuration of an interchangeable lens 100 (optical device) in a first embodiment of the present invention will be described below with reference to Figs. 1 and 2. Fig. 1 is a cross-sectional view taken along a plane parallel to an optical axis O at the wide-angle end (wide end) of the interchangeable lens 100 in this embodiment. Fig. 2 is an exploded perspective view of the main parts in the first embodiment.

[0011] The interchangeable lens 100 of this embodiment is an optical device with a seven-group configuration consisting of a first lens group L1 to a seventh lens group L7 (hereinafter referred to as "each lens group"). A focusing operation in the interchangeable lens 100 moves the fourth lens group L4, which is the first floating lens group, the fifth lens group L5, which is the second floating lens group, and the sixth lens group L6, which is the focus lens group, in the optical axis direction. These moving lens groups will be referred to as moving lens groups hereinafter.

[0012] Furthermore, all of the movable lens groups move in the optical axis direction along predetermined trajectories due to zooming operation (zooming, variable magnification operation) in the interchangeable lens 100. At this time, the control unit 119 drives and controls the fourth lens group L4, the fifth lens group L5, and the sixth lens group L6 so that the focus position and the amount of each aberration changed by the zooming operation are kept below a certain level.

[0013] 6, the camera body 1a is an imaging device body equipped with an imaging element 1b such as a CCD or CMOS. The interchangeable lens 100 is held detachably in the camera body 1a, and the interchangeable lens 100 and the camera body 1a constitute a camera system.

[0014] The lens mount 111 has a bayonet portion for mounting the interchangeable lens 100 to the camera body 1a, and is fixed to the rear fixed barrel 112 with screws via an exterior barrel 113. The exterior barrel 113 is fixed by being sandwiched between the lens mount 111 and the rear fixed barrel 112. The front fixed barrel 115 is fixed to the rear fixed barrel 112 with screws, and a zoom index and an operation switch (not shown) are attached to the front fixed barrel 115. The guide barrel 116 is fixed to the rear fixed barrel 112 with screws.

[0015] A linear groove that guides each lens group in a linear direction is formed in the guide barrel 116. A cam groove is also formed in the guide barrel 116, and the cam barrel 117 is held so that it can be rotated and extended by zooming by a cam follower (not shown) fixed to the cam barrel 117 with a screw. Three types of cam grooves are formed in the cam barrel 117, each of which corresponds to the trajectory of each lens group during zoom operation.

[0016] The zoom operation tube 118 is radially fitted into the guide tube 116 and is held by a bayonet so as to be rotatable about the optical axis. The rotational force of the zoom operation tube 118 is converted into linear movement of the linear movement tube 122 by the action of a cam groove provided in the zoom operation tube 118, a cam follower provided on the outside of the linear movement tube 122, and the linear movement groove of the guide tube 116, and the linear movement tube 122 moves linearly due to zoom operation.

[0017] Here, a cam follower (not shown) provided on the linear barrel 122 also engages with a cam groove of the cam barrel 117, and the linear movement of the linear barrel 122 is converted into the rotational movement of the cam barrel 117. As described above, the cam barrel 117 is held so as to be rotatable and extendable relative to the guide barrel 116. As a result, the linear movement of the linear barrel 122 enables the cam barrel 117 to be rotatable and extendable relative to the optical axis O.

[0018] The rear group unit (not shown) and the seventh group unit (not shown) are configured to be drivable with respect to the optical axis O by utilizing the force of the cam barrel 117 rotating and extending relative to the guide barrel 116. More specifically, the rear group unit and the seventh group unit are driven by the action of rear group cam followers 123A, 123B, and 123C (engagement portions, see FIG. 2) described below, the seventh group cam followers (not shown) and the respective linear grooves and cam grooves. As described above, the mechanical movement of each lens group in this embodiment is a basic operation in which, due to the rotation of the zoom ring, (1) the linear barrel 122 extends linearly, (2) the cam barrel 117 rotates and extends, and (3) each group other than the first group extends linearly.

[0019] Next, each lens group will be described in detail. The first lens holding frame 101 is a holding frame that holds the first lens group L1. The first lens holding frame 101 is fixed to a linear cylinder 122 that is moved linearly by a linear groove, a cam groove, and a cam follower using screws. In addition, a first lens pressing ring 125 has a screw groove formed on its inner diameter, and is fixed by being screwed into a screw formed on the outer shape of the linear cylinder 122, at which time it plays a role in fixing the first lens group L1.

[0020] Furthermore, the filter frame 120 is fixed to the linear cylinder 122 with screws, and has a bayonet portion for attaching a hood on the outer periphery and a screw on the inner periphery, allowing accessories such as a filter to be attached.

[0021] The second lens retaining frame 102 is a retaining frame that retains the second lens group L2. The second lens retaining frame 102 constitutes a part of a shake correction unit 108. The shake correction unit 108 holds the second lens retaining frame 102 so that it can be driven in a direction perpendicular to the optical axis O (direction perpendicular to the optical axis), and performs shake correction by driving the second lens retaining frame 102 with a shake correction driving unit composed of a magnet, a coil, etc. The shake correction unit 108 is suspended and held by a guide cylinder 116 by a cam follower (not shown).

[0022] The third lens holding frame 103 is a holding frame that holds the third lens group L3. The third lens holding frame 103 is engaged with and held by a rear group base 126 (base member) by three cam followers, and is moved forward and backward in the optical axis direction by zooming operation by rear group cam followers 123A, 123B, and 123C provided on the rear group base 126. The third lens holding frame 103 also holds an electromagnetic diaphragm unit 110 that is configured with an diaphragm drive unit and an diaphragm blade unit.

[0023] The fourth lens holding frame 104 as a first holding member is a holding frame that holds the fourth lens group L4 as a first optical element that is a first floating group. The movement of the fourth lens holding frame 104 in the optical axis direction is guided by a first guide means 151. The fourth lens group L4 (or the fourth lens holding frame 104) advances and retreats in the optical axis direction as the rear group base 126 zooms, and is further driven in the optical axis direction by a first drive unit 161 that is a drive section relative to the rear group base 126.

[0024] Here, the driving force transmission mechanism included in the first drive unit 161 is composed of a motor stator (not shown) and a motor movable element (not shown) that constitute the motor, and a motor driving transmission section that is a part of the movable element. Furthermore, the motor driving transmission section is composed of a first rack 132 that is a driving transmission member that transmits the driving force of the motor to the fourth lens retaining frame 104, and a first rack biasing spring 133 (first biasing member) that biases the first rack 132 and the motor driving transmission section to remove backlash.

[0025] The fourth lens holding frame 104 is provided with a scale for detecting a position in the optical axis direction. Also, a corresponding optical sensor is provided on the rear group base 126 via a flexible printed circuit board (FPC), and the scale and the optical sensor together constitute a first floating position detection means.

[0026] The fifth lens holding frame 105 as the second holding member is a holding frame that holds the fifth lens group L5 as the second optical element that is the second floating group. The movement of the fifth lens holding frame 105 in the optical axis direction is guided by the second guide means 152. The fifth lens holding frame 105 advances and retreats in the optical axis direction when the rear group base 126 zooms, and is further driven in the optical axis direction by the second drive unit 162 that is a drive section relative to the rear group base 126. The drive force transmission mechanism included in the second drive unit 162 has a similar configuration to the drive force transmission mechanism included in the first drive unit 161 that drives the fourth lens group L4.

[0027] The sixth lens holding frame 106 as the third holding member is a holding frame that holds the sixth lens group L6 as the third optical element that is a focus group. The movement of the sixth lens holding frame 106 in the optical axis direction is guided by the third guide means 153. The sixth lens holding frame 106 advances and retreats in the optical axis direction by the zoom operation of the rear group base 126, and is further driven in the optical axis direction by the third drive unit 163 that is a drive unit relative to the rear group base 126. The drive force transmission mechanism included in the third drive unit 163 has the same configuration as the drive force transmission mechanism included in the first drive unit 161 that drives the fourth lens group L4. The fourth lens holding frame 104, the fifth lens holding frame 105, and the sixth lens holding frame 106 that move are hereinafter referred to as a moving group.

[0028] The seventh lens retaining frame 107 is a retaining frame that retains the seventh lens group L7. The seventh lens retaining frame 107 is screwed and fixed to the seventh group base 109, and is moved forward and backward in the optical axis direction by zooming together with the seventh group base 109 by three cam followers provided on the seventh group base 109.

[0029] In this embodiment, when driving the fourth lens retaining frame 104, the fifth lens retaining frame 105, and the sixth lens retaining frame 106, a motor using a piezoelectric element is used, and a configuration is made in which a motor movable element (not shown) can be driven in the optical axis direction relative to a motor stator (not shown). However, a similar configuration is also possible using, for example, a stepping motor, with the movable element and the motor drive transmission unit as a lead screw shaft and a mechanism connected to a rack. When using a stepping motor, it is also possible to eliminate the detection system and control it as an open drive.

[0030] In this embodiment, the first to third drive units 161-163 as the multiple drive means are fixed to the rear group base 126, but may be configured to be held movably in the optical axis direction relative to the rear group base 126. The first to third drive units 161-163 may overlap each other at least partially in the optical axis direction. Furthermore, the multiple drive means may be configured by two units, or four or more units.

[0031] The zoom operation tube 118 has a groove formed therein into which a movable element of a resistive linear sensor 134 (potentiometer) which is a zoom position detection means (not shown) fixed to the guide tube 116 fits. The output of the resistive linear sensor 134 changes according to the amount of rotation of the zoom operation tube 118, making it possible to detect zoom position information.

[0032] The focus operation tube 114 is sandwiched between the front fixed tube 115 and the rear fixed tube 112 so that it can rotate at a fixed position outside the front fixed tube 115. The amount and direction of rotation of the focus operation tube 114 are detected by a light detection element (not shown) provided on the front fixed tube 115 and a black and white light and dark scale (not shown) provided on the inner diameter of the focus operation tube 114.

[0033] The multipurpose operation tube 121 is sandwiched between the rear fixed tube 112 and the exterior tube 113 so as to be able to rotate at a fixed position outside the rear fixed tube 112. As with the focus operation tube 114, the amount and direction of rotation of the multipurpose operation tube 121 are detected by a photodetector element (not shown) provided on the rear fixed tube 112 and a scale (not shown) having black and white light and dark provided on the inner diameter of the multipurpose operation tube 121. In addition, the multipurpose operation tube 121 and the rear fixed tube 112 are provided with a click mechanism consisting of a click pin, groove, and spring for the purpose of giving the user a clicking sensation, and a configuration is also possible whereby the click position can be detected by the black and white light and dark pattern of the scale.

[0034] The control means 119 controls the entire interchangeable lens 100, including focus drive control, the electromagnetic aperture unit 110, and the shake correction unit 108, and is fixed to the rear fixed cylinder 112 with screws.

[0035] Next, the configuration of the main parts of the interchangeable lens 100 will be described with reference to Figures 2 and 3. Figure 3 is a cross-sectional view of the main parts in Example 1. The third lens group L3 to the sixth lens group L6 are held by a rear group base 126 that is moved in the optical axis direction by zooming operation. For convenience, Figure 2 shows the fourth lens holding frame 104 to the sixth lens holding frame 106 that correspond to the fourth lens group L4 to the sixth lens group L6.

[0036] The first guiding means 151 is configured by a pair of guide members (two guide bars) including a first main shaft 151A (one member) and a first counter shaft 151B (the other member). One end of the first main shaft 151A is held by the rear group base 126, and the other end is held by a first rear group cover 127 fastened and fixed to the rear group base 126. One end of the first counter shaft 151B is held by the rear group base 126, and the other end is held by a third rear group cover 129.

[0037] The first main shaft 151A and the first sub-shaft 151B guide the movement of the fourth lens retaining frame 104 in the optical axis direction, and the first main shaft 151A engages with a sleeve hole 104a of the fourth lens retaining frame 104. In addition, a first rack 132 and a first rack biasing spring 133 are provided on the fourth lens retaining frame 104, and the first rack biasing spring 133 generates a biasing force that rotates the first rack 132 that is rotatably provided.

[0038] A movable portion of the first drive unit 161 and the first rack 132 engage at a location not shown, and a rotation moment about the axis of the first main shaft 151A is generated in the fourth lens retaining frame 104 by the biasing force of the first rack biasing spring 133. In addition, the first rack biasing spring 133 biases the first sub-shaft 151B so that the first sub-shaft 151B abuts on the U-groove 104b of the fourth lens retaining frame 104, and the position of the fourth lens retaining frame 104 relative to the rear group base 126 is determined by this biasing force.

[0039] The position of the fourth lens retaining frame 104 in the optical axis direction relative to the rear group base 126 is read by detecting a scale (not shown) fixed to the fourth lens retaining frame 104 with a first position sensor 159 as a first detection means fixed to the rear group base 126.

[0040] The second guide means 152 is configured by a pair of guide members (two guide bars) including a second main shaft 152A (one member) and a second counter shaft 152B (the other member). One end of the second main shaft 152A is held by the rear group base 126, and the other end is held by a second rear group cover 128 fastened and fixed to the rear group base 126. One end of the second counter shaft 152B is held by the rear group base 126, and the other end is held by a first rear group cover 127.

[0041] The second main shaft 152A and the second sub-shaft 152B guide the movement of the fifth lens retaining frame 105 in the optical axis direction, and the second main shaft 152A engages with a sleeve hole 105a of the fifth lens retaining frame 105. In addition, a second rack and a second rack biasing spring (second biasing member) (not shown) are provided on the fifth lens retaining frame 105, and the second rack biasing spring generates a biasing force that rotates the rotatably provided second rack.

[0042] The movable part of the second drive unit 162 and the second rack are engaged at a location not shown, and the biasing force of the second rack biasing spring generates a rotation moment around the axis of the second main shaft 152A in the fifth lens retaining frame 105. In addition, the second rack biasing spring biases the second sub-shaft 152B so that the second sub-shaft 152B abuts against the U-groove 105b of the fifth lens retaining frame 105, and the position of the fifth lens retaining frame 105 with respect to the rear group base 126 is determined by this biasing force.

[0043] The position of the fifth lens retaining frame 105 in the optical axis direction relative to the rear group base 126 is read by detecting a scale (not shown) fixed to the fifth lens retaining frame 105 with a second position sensor (not shown) as a second detection means fixed to the rear group base 126.

[0044] The third guide means 153 is configured by a pair of guide members (two guide bars) including a third main shaft 153A (one member) and a third counter shaft 153B (the other member). One end of the third main shaft 153A is held by the rear group base 126, and the other end is held by a third rear group cover 129 fastened and fixed to the rear group base 126. One end of the third counter shaft 153B is held by the rear group base 126, and the other end is held by the second rear group cover 128.

[0045] The third main shaft 153A and the third sub-shaft 153B guide the movement of the sixth lens retaining frame 106 in the optical axis direction, and the third main shaft 153A engages with a sleeve hole 106a of the sixth lens retaining frame 106. In addition, a third rack and a third rack biasing spring (third biasing member) (not shown) are provided on the sixth lens retaining frame 106, and the third rack biasing spring generates a biasing force that rotates the rotatably provided third rack.

[0046] A movable portion of the third drive unit 163 and the third rack are engaged at a location not shown, and a rotation moment about the axis of the third main shaft 153A is generated in the sixth lens retaining frame 106 by the biasing force of the third rack biasing spring. In addition, the third rack biasing spring biases the third sub-shaft 153B so that the third sub-shaft 153B abuts against the U-groove 106b of the sixth lens retaining frame 106, and the position of the sixth lens retaining frame 106 with respect to the rear group base 126 is determined by this biasing force.

[0047] The position of the sixth lens retaining frame 106 in the optical axis direction relative to the rear group base 126 is read by detecting a scale (not shown) fixed to the sixth lens retaining frame 106 with a third position sensor (not shown) serving as a third detection means (third detection means) fixed to the rear group base 126.

[0048] Rear group cam followers 123A, 123B, and 123C for holding the rear group base 126 to another member are provided on the rear group base 126 at three locations in the circumferential direction centered on the optical axis O of the rear group base 126. The rear group base 126 is engaged with and held by the guide barrel 116 and the cam barrel 117 by the three rear group cam followers 123A, 123B, and 123C.

[0049] In this embodiment, the fourth lens group L4 is the first floating group, the fifth lens group L5 is the second floating group, and the sixth lens group L6 is the focus group, and it has been described that these three lens groups are driven during focus adjustment, but this is not limited to this. One may be a moving group that moves during magnification change and the other during focus adjustment. Note that a floating mechanism that moves two moving groups during focus adjustment is used to correct two variables, the focus position and the field curvature, but a floating mechanism that moves three moving groups during focus adjustment is used to correct three variables, the focus position, the spherical aberration, and the field curvature.

[0050] The arrangement of the members constituting the main part of this embodiment will be described in detail with reference to Fig. 3. The first axis AX1, the second axis AX2, and the third axis AX3 are each an axis that passes through the center of the rear group cam followers 123A, 123B, and 123C with the optical axis O as the origin. Since the rear group cam followers 123A, 123B, and 123C are arranged in approximately three equal parts, the angle formed by each of the first to third axes AX1 to AX3 is approximately 120 degrees.

[0051] In this embodiment, the first axis AX1, the second axis AX2, and the third axis AX3 are axes passing through the rear group cam followers 123A, 123B, and 123C, respectively, but are not limited thereto. For example, the rear group cam followers 123A, 123B, and 123C may be cam followers that hold the fourth holding member that holds the fourth optical element on the rear group base 126. Furthermore, instead of cam followers, they may be mounting parts such as screw fastening parts. Even in this form, by arranging the drive unit and the guide member in different areas, the mounting parts can be secured near the boundaries of each area. Since there is no need to increase the size in order to secure the mounting parts, this leads to miniaturization.

[0052] When the area surrounded by the first axis AX1 and the second axis AX2 is defined as a first area AR1, the area surrounded by the second axis AX2 and the third axis AX3 is defined as a second area AR2, and the area surrounded by the third axis AX3 and the first axis AX1 is defined as a third area AR3, the components are arranged as follows.

[0053] The first region AR1 is provided with the first driving unit 161, the first rack 132, the first rack biasing spring 133, the first main shaft 151A, and the second counter shaft 152B. The second region AR2 is provided with the second driving unit 162, the second rack, the second rack biasing spring, the second main shaft 152A, and the third counter shaft 153B. The third region AR3 is provided with the third driving unit 163, the third rack, the third rack biasing spring, the third main shaft 153A, and the first counter shaft 151B. The effects of this arrangement will be described below.

[0054] In this embodiment, the first to third driving units 161 to 163 driven electrically are used to drive the lens groups of the fourth lens group L4 to the sixth lens group L6, and the lens groups are arranged close to each other. In this embodiment, the driving units and the guide members are arranged in different regions, so that the mounting parts of the cam followers can be secured near the boundaries of the regions, leading to a reduction in the size of the device. In addition, the positioning method in the plane perpendicular to the optical axis O of each lens holding frame is performed by engaging each sleeve hole and each main shaft of each lens holding frame as described above, and the positioning of the rotation around the axis of each sleeve hole is performed by each U-groove and each sub-shaft of each lens holding frame. When considering the movement restriction end in the optical axis direction of each lens holding frame, since the positioning part in the plane perpendicular to the optical axis described above becomes the sliding part, it is suitable for the positioning accuracy to provide the movement restriction end near the sliding part.

[0055] On the other hand, when considering the inertial force caused by the acceleration generated when an impact is applied to each lens holding frame, the inertial force generated in the mass of the optical system and each lens holding frame and other members acts on the center of gravity of these moving groups. Generally, the mass of the optical system, i.e., the lenses, is the largest, so the inertial force is generated near the optical center.

[0056] Therefore, the best position for the movement restriction end in the optical axis direction when an impact is applied is one in which the midpoints of the lines connecting the main and sub axes are located near the center of gravity of each moving group when viewed from the optical axis direction. This is because, as described above, by making the force acting on the movement restriction end approximately the same when an impact is applied, the effect of the reaction after acting on the restriction end can be minimized.

[0057] From this viewpoint, it is also important that each line segment connecting each main shaft and each sub-shaft is close to the center of gravity. This is because when an impact is applied to each lens holding frame and it collides with the movement restricting end, by shortening the distance between each line segment connecting each main shaft and each sub-shaft and the center of gravity, the moment that tends to tilt around the axis of each line segment connecting each main shaft and each sub-shaft due to the generated reaction force is reduced.

[0058] In this embodiment, a pair of main shafts and sub shafts corresponding to the same lens holding frame are arranged not to be in the same region, and are arranged so that the sub shafts are positioned in adjacent regions in the clockwise direction in Fig. 3 relative to the main shafts. Note that this arrangement is such that a combination of a set of drive units and guide members is arranged to be spaced apart by approximately 120 degrees and approximately 240 degrees around the optical axis O. As described above, this arrangement works well with the rear group cam followers 123A, 123B, and 123C being arranged in approximately three equal parts in the circumferential direction of the rear group base 126, and this allows for miniaturization and improved impact resistance.

[0059] With this configuration, in all three moving groups, the distance between the line segment connecting the main shaft and the secondary shaft and the optical axis O can be shorter than the radius of the lens group, or the midpoint of each line segment can be located within the effective diameter of each lens group. As an example, FIG. 3 shows that when the line segment connecting the first main shaft 151A and the first secondary shaft 151B, which are a pair of guide members, is defined as the first line segment A1, the first distance D1 (distance) between the first line segment A1 and the optical axis O is shorter than the radius R1 of the fourth lens group L4. Or, it shows that the first midpoint C1, which is the midpoint of the first line segment A1, is within the effective diameter of the fourth lens group L4. Similarly, when the line segment connecting the second main shaft 152A and the second secondary shaft 152B, which are a pair of guide members, is defined as the second line segment A2, the second distance (not shown) between the second line segment A2 and the optical axis O is shorter than the radius (not shown) of the fifth lens group L5. Alternatively, the midpoint (not shown) of the second line segment A2 is within the effective diameter of the fifth lens group L5. Similarly, when a line segment connecting the third main shaft 153A and the third sub shaft 153B, which are a pair of guide members, is defined as a third line segment A3, a third distance A3 between the third line segment A3 and the optical axis O is shorter than the radius (not shown) of the sixth lens group L6. Alternatively, the midpoint (not shown) of the third line segment A3 is within the effective diameter of the sixth lens group L6.

[0060] When considering the position of the center of gravity of the moving group, the lens group which is the optical system has the greatest mass, so by arranging it as described above, it is possible to bring each line segment close to the position of the center of gravity of each moving group, thereby obtaining a compact size and high impact resistance.

[0061] In this embodiment, the guide members are arranged so that the first to third line segments A1 to A3 intersect when viewed from the optical axis direction. This configuration makes it easier to bring the line segments connecting the main shafts and the sub shafts closer to the center of gravity, thereby improving impact resistance.

[0062] This arrangement not only provides high impact resistance, but also improves the holding accuracy of each lens holding frame by allowing each sleeve hole and each U-groove to be positioned as far apart as possible. For example, the distance A (first line segment A1) between the first main axis 151A and the first sub-axis 151B, the distance B from the first main axis 151A to the optical axis O, and the component of the position error of the first sub-axis 151B and the U-groove 104b that is perpendicular to the line connecting the first main axis 151A and the first sub-axis 151B is δ. In this case, the holding accuracy of the optical system is represented by δB / A, and it can be seen that the holding accuracy of the fourth lens holding frame 104 is improved.

[0063] As described above, according to the first embodiment, it is possible to provide a small-sized optical device with high impact resistance in which three electric drive units are used to move three lens groups to perform focus adjustment and zooming.

[0064] In this embodiment, the main shaft and the sub shaft (paired with the main shaft in the adjacent region) in each region are placed close to each other so that they can be held by the same rear group cover, but this is not limiting. For example, it is also possible to realize an efficient arrangement when viewed from the optical axis direction by treating the main shaft and the sub shaft in each region as the same part.

[0065] Furthermore, in this embodiment, it has been described that each lens holding frame driven by each drive unit is biased by each rack spring in a plane perpendicular to the optical axis O, but this is not limited to this. For example, a biasing means other than a rack spring may be used, or a biasing means may not be provided and a means may be used to suppress backlash between each main shaft and each sleeve hole, and between each sub shaft and each U-groove. It is clear that the above-mentioned effects can be obtained even with such a configuration.

[0066] In this embodiment, the drive unit is an ultrasonic motor, but is not limited to this. For example, it may be a stepping motor, a lead screw, or a voice coil motor, or a combination of these. Furthermore, the drive unit is not limited to being electrically driven, and may be, for example, a drive force in the optical axis direction obtained from the rotation of a cam barrel to drive the holding member in the optical axis direction.

[0067] Example 2 In Example 1, each major axis and each minor axis (which is paired with a major axis in an adjacent region) in each region was arranged close to one boundary of the region, but in Example 2, the major axes are close to one boundary of the region, and the minor axes are close to the other boundary of the region.

[0068] In addition, in Example 1, the second optical element is the fifth lens group L5, and the third optical element is the sixth lens group L6, but this is different in Example 2. Specifically, the second optical element is the sixth lens group L6, and the third optical element is the fifth lens group L5. The configuration of each lens group is unchanged from Example 1.

[0069] FIG. 4 is a cross-sectional view of the main part in the second embodiment. The fourth lens group L4 in the second embodiment is driven by the first driving unit 261, and is held by the first main shaft 251A (one member) and the first sub-shaft 251B (the other member), which are a pair of guide members constituting the first guide means 251. The sixth lens group L6 is driven by the second driving unit 262, and is held by the second main shaft 252A (one member) and the second sub-shaft 252B (the other member), which are a pair of guide members constituting the second guide means 252. The fifth lens group L5 is driven by the third driving unit 263, and is held by the third main shaft 253A (one member) and the third sub-shaft 253B (the other member), which are a pair of guide members constituting the third guide means 253. In the second embodiment, the arrangement of the rear group cam followers 123A and 123B is different from that in the first embodiment, and therefore the arrangement of the first axis AX1 and the second axis AX2 is also different.

[0070] When the area surrounded by the first axis AX1 and the second axis AX2 is the first area ARl, the area surrounded by the second axis AX2 and the third axis AX3 is the second area AR2, and the area surrounded by the third axis AX3 and the first axis AX1 is the third area AR3, the components are arranged as follows.

[0071] In the first region AR1, the first driving unit 261, the first rack (not shown), the first rack biasing spring (not shown), the first main shaft 251A, and the second countershaft 252B are arranged. In the second region AR2, the second driving unit 262, the second rack (not shown), the second rack biasing spring (not shown), the second main shaft 252A, and the third countershaft 253B are arranged. In the third region AR3, the third driving unit 263, the third rack (not shown), the third rack biasing spring (not shown), the third main shaft 253A, and the first countershaft 251B are arranged.

[0072] With this configuration, it is possible to arrange the midpoints of the line segments connecting the main shafts and the sub-shafts, which are a pair of guide members, near the optical axis. The best arrangement for restricting movement in the optical axis direction when an impact is applied is one in which the midpoints of the line segments connecting the main shafts and the sub-shafts are located near the center of gravity of the moving group when viewed from the optical axis direction, and this embodiment is exactly that, so it is possible to further improve impact resistance. This arrangement not only provides high impact resistance, but also improves the holding accuracy of each lens holding frame by allowing the sleeve holes and U-grooves to be arranged as far apart as possible, as explained in the first embodiment.

[0073] 4, a line segment connecting the first main shaft 251A and the first sub-shaft 251B, which are a pair of guide members, is shown as a first line segment A1, a line segment connecting the second main shaft 252A and the second sub-shaft 252B is shown as a second line segment A2, and a line segment connecting the third main shaft 253A and the third sub-shaft 253B is shown as a third line segment A3. When viewed from the optical axis direction, these first to third line segments A1 to A3 pass substantially through the optical axis O, but are not limited to this. It is clear from the above description that when the center of gravity positions of each moving group are different, it is more preferable to arrange each midpoint of each line segment in the vicinity of the center of gravity.

[0074] That is, when the center of gravity of the fourth lens group L4 driven by the first driving unit 261 is defined as the first center of gravity, the first line segment A1 passes through the first center of gravity, or the midpoint (not shown) of the first line segment A1 and the first center of gravity are substantially coincident. Similarly, when the center of gravity of the sixth lens group L6 driven by the second driving unit 262 is defined as the second center of gravity, the second line segment A2 passes through the second center of gravity, or the midpoint (not shown) of the second line segment A2 and the second center of gravity are substantially coincident. Also, when the center of gravity of the fifth lens group L5 driven by the third driving unit 263 is defined as the third center of gravity, the third line segment A3 passes through the third center of gravity, or the midpoint (not shown) of the third line segment A3 and the third center of gravity are substantially coincident.

[0075] As described above, according to the second embodiment, it is possible to provide a small-sized optical device with high impact resistance in which three lens groups are moved using three electrical drive units to perform focus adjustment and zooming.

[0076] Example 3 In Example 1, the main axis and the secondary axis are disposed close to one boundary of the region, but in Example 3, the main axis is disposed close to one boundary of the region, and the secondary axis is disposed close to the other boundary of the region. Also, the members corresponding to the second and third claims in Example 3 have the same corresponding relationship as in Example 1.

[0077] 5 is a cross-sectional view of the main part in the third embodiment. The fourth lens group L4 in the third embodiment is driven by the first driving unit 361, and is held by the first main shaft 351A (one member) and the first sub-shaft 351B (the other member), which are a pair of guide members constituting the first guide means 351. The fifth lens group L5 is driven by the second driving unit 362, and is held by the second main shaft 352A (one member) and the second sub-shaft 352B (the other member), which are a pair of guide members constituting the second guide means 352. The sixth lens group L6 is driven by the third driving unit 363, and is held by the third main shaft 353A (one member) and the third sub-shaft 353B (the other member), which are a pair of guide members constituting the third guide means 353.

[0078] The definitions of the first to third axes AX1 to AX3 and the first to third regions AR1 to AR3 are the same as those in the first embodiment. In the first region AR1, the first driving unit 361, the first rack (not shown), the first rack biasing spring (not shown), the first main shaft 351A, and the second countershaft 352B are arranged. In the second region AR2, the second driving unit 362, the second rack (not shown), the second rack biasing spring (not shown), the second main shaft 352A (one member), and the third countershaft 353B are arranged. In the third region AR3, the third driving unit 363, the third rack (not shown), the third rack biasing spring (not shown), the third main shaft 353A, and the first countershaft 351B are arranged.

[0079] 5, a line segment connecting the first main shaft 351A and the first counter shaft 351B, which are a pair of guide members, is shown as a first line segment A1, a line segment connecting the second main shaft 352A and the second counter shaft 352B is shown as a second line segment A2, and a line segment connecting the third main shaft 353A and the third counter shaft 353B is shown as a third line segment A3. In the first and second embodiments, the line segments are arranged so that there are intersections between them, but in the third embodiment, there is no intersection between them.

[0080] As described above, according to the third embodiment, it is possible to provide a small-sized optical device with high impact resistance in which three electric drive units are used to move three lens groups to perform focus adjustment and zooming.

[0081] 5 that, for example, the first distance D1 between the first midpoint C1 of the first line segment A1 connecting the first main shaft 351A and the first sub shaft 351B and the center of gravity position of the moving group is long when compared with Example 1 or 2, but there are the following advantages: In Example 3, the sleeve holes and U-grooves formed in each lens holding frame can be disposed close to each other, so that the interchangeable lens 100 can be further miniaturized while improving impact resistance.

[0082] (Examples) 6 is a schematic diagram showing an example of the configuration of a camera device 1 (imaging device) that uses an interchangeable lens 100 (interchangeable lens for a single-lens reflex camera) to which the present invention is applied. The imaging device includes the interchangeable lens 100 and the camera device 1 that is made up of a camera body 1a having an image sensor 200b that receives light from the interchangeable lens 100. The imaging device is configured such that the interchangeable lens 100 is detachably attached to the camera body 1a of the camera device 1, but the camera body 1a and the interchangeable lens 100 may also be configured as one unit.

[0083] 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 present invention.

[0084] The disclosure of this embodiment includes the following configuration. (Configuration 1) a first holding member that holds a first optical element, a second holding member that holds a second optical element, and a third holding member that holds a third optical element; a first guide means for guiding the movement of the first holding member, a second guide means for guiding the movement of the second holding member, and a third guide means for guiding the movement of the third holding member; A plurality of drive means; a base member for holding the plurality of driving means, The first, second, and third guide means each include a pair of guide members including one member and the other member, The base member is provided with three engagement portions in a circumferential direction centered on an optical axis of the base member, When axes passing through the optical axis and each of the engagement portions are defined as first, second, and third axes, respectively, one member of the first guide means and the other member of the second guide means are disposed in a first region between the first shaft and the second shaft, one member of the second guide means and the other member of the third guide means are disposed in a second region between the second shaft and the third shaft, An optical device, characterized in that one member of said third guiding means and the other member of said first guiding means are disposed in a third region between said third axis and said first axis. (Configuration 2) 3. The optical device according to configuration 2, wherein when viewed from the optical axis direction, the three line segments connecting each pair of the guide members each have an intersection point. (Configuration 3) The optical device described in configuration 1 or 2, characterized in that when viewed from the optical axis direction, the three line segments connecting each pair of guide members pass through the optical axes of the first, second, and third optical elements. (Configuration 4) When the line segments connecting the pair of guide members are respectively defined as first, second, and third line segments, when viewed from the optical axis direction, a first distance between the first line segment and the optical axis is shorter than a radius of the first optical element, or a midpoint of the first line segment is within an effective diameter of the first optical element; a second distance between the second line segment and the optical axis is less than a radius of the second optical element, or a midpoint of the second line segment is within an effective diameter of the second optical element; The optical device described in configuration 1, characterized in that a third distance between the third line segment and the optical axis is shorter than a radius of the third optical element, or a midpoint of the third line segment is within an effective diameter of the third optical element. (Configuration 5) the plurality of driving means include first, second and third driving units configured to drive the first, second and third holding members in the optical axis direction, respectively; The center of gravity of the moving group driven by the first drive unit is referred to as a first center of gravity position, The center of gravity of the moving group driven by the second drive unit is referred to as a second center of gravity position. The center of gravity of the moving group driven by the third drive unit is called a third center of gravity position. When viewed from the optical axis direction, the first line segment substantially passes through the first center of gravity position, or a midpoint of the first line segment substantially coincides with the first center of gravity position, the second line segment substantially passes through the second center of gravity position, or a midpoint of the second line segment substantially coincides with the second center of gravity position, The optical device according to configuration 4, wherein the third line segment substantially passes through the third center of gravity position, or a midpoint of the third line segment substantially coincides with the third center of gravity position. (Configuration 6) The optical device according to any one of configurations 1 to 5, wherein the first, second, and third drive units overlap each other in at least a partial range in the optical axis direction. (Configuration 7) the first, second, and third biasing members are provided to generate biasing forces so as to bring the first, second, and third holding members into contact with the other members of the first, second, and third guiding means, respectively; 7. The optical device according to any one of configurations 1 to 6, wherein the first, second, and third biasing members are disposed in the first, second, and third regions, respectively. (Configuration 8) The optical device according to any one of configurations 1 to 7, wherein any one of the first, second and third optical elements moves in the optical axis direction during zooming or focusing. (Configuration 9) The optical device according to any one of configurations 1 to 8, wherein the engagement portion causes a fourth holding member that holds a fourth optical element to be held on the base member. (Configuration 10) An imaging device comprising: the optical device according to any one of configurations 1 to 9; and an imaging element that receives light from the optical device. (Configuration 11) 11. The imaging device according to configuration 10, wherein the optical device is detachably attached to the imaging device. [Explanation of symbols]

[0085] 100 Interchangeable lenses (optical devices) 104 fourth lens holding frame (first holding member) 105 fifth lens holding frame (second holding member) 106 sixth lens holding frame (third holding member) 123A~123C Rear group cam follower (engagement part) 126 Rear group base (base material) 133 First rack biasing spring (first biasing member) 151 to 153 First guide means to third guide means 251 to 253 First guide means to third guide means 351 to 353 First guide means to third guide means 151A~351A First spindle (one of the components) 151B~351B First auxiliary shaft (other member) 152A~352A Second spindle (one of the components) 152B~352B Second auxiliary shaft (other member) 153A~353A 3rd spindle (one of the components) 153B~353B 3rd countershaft (other member) 161~163 1st drive unit ~ 3rd drive unit 261~263 1st drive unit~3rd drive unit AX1~AX3 1st axis~3rd axis AR1~AR3 1st area~3rd area C1 midpoint D1 First distance (distance) A1~A3 1st line segment~3rd line segment L4 Fourth lens group (first optical element) L5 Fifth lens group (second optical element, third optical element) L6 6th lens group (3rd optical element, 2nd optical element) R1 radius O optical axis

Claims

1. A first holding member that holds a first optical element, a second holding member that holds a second optical element, and a third holding member that holds a third optical element, a pair of first guiding members that guide the movement of the first holding member, a pair of second guiding members that guide the movement of the second holding member, and a pair of third guiding members that guide the movement of the third holding member, Among the regions divided into three parts around the optical axis in the circumferential direction, when the region where one of the pair of first guiding members is arranged is the first region, the region where one of the pair of second guiding members is arranged is the second region, and the region where one of the pair of third guiding members is arranged is the third region, the other of the pair of second guiding members is arranged in the first region, the other of the pair of third guiding members is arranged in the second region, and the other of the pair of first guiding members is arranged in the third region. An optical device characterized by this.

2. When viewed from the optical axis direction, a first line segment connecting the pair of first guiding members to each other, a second line segment connecting the pair of second guiding members to each other, and a third line segment connecting the pair of third guiding members to each other intersect each other. The optical device according to claim 1, characterized by this.

3. When viewed from the optical axis direction, a first line segment connecting the pair of first guiding members to each other, a second line segment connecting the pair of second guiding members to each other, and a third line segment connecting the pair of third guiding members to each other intersect the optical axis. The optical device according to claim 1, characterized by this.

4. When viewed from the optical axis direction, a first distance between the first line segment connecting the pair of first guiding members to each other and the optical axis is shorter than the radius of the first optical element, a second distance between the second line segment connecting the pair of second guiding members to each other and the optical axis is shorter than the radius of the second optical element, and a third distance between the third line segment connecting the pair of third guiding members to each other and the optical axis is shorter than the radius of the third optical element. The optical device according to claim 1, characterized by this.

5. When viewed from the optical axis direction, the midpoint of the first line segment connecting the pair of first guiding members to each other is within the effective region of the first optical element, the midpoint of the second line segment connecting the pair of second guiding members to each other is within the effective region of the second optical element, and the midpoint of the third line segment connecting the pair of third guiding members to each other is within the effective region of the third optical element. The optical device according to claim 1, characterized by this.

6. The optical device according to claim 1, wherein when viewed from the optical axis direction, a first line segment connecting the pair of first guide members passes through the center of gravity of the first holding member, a second line segment connecting the pair of second guide members passes through the center of gravity of the second holding member, and a third line segment connecting the pair of third guide members passes through the center of gravity of the third holding member.

7. The optical device according to claim 1, wherein when viewed from the optical axis direction, the midpoint of a first line segment connecting the pair of first guide members is at the center of gravity of the first holding member, the midpoint of a second line segment connecting the pair of second guide members is at the center of gravity of the second holding member, and the midpoint of a third line segment connecting the pair of third guide members is at the center of gravity of the third holding member.

8. The optical device according to claim 1, further comprising: a first driving unit configured to move the first holding member; a second driving unit configured to move the second holding member; and a third driving unit configured to move the third holding member.

9. The optical device according to claim 1, wherein a part of each of the first driving unit, the second driving unit, and the third driving unit is located in a common plane perpendicular to the optical axis.

10.

11. The optical device according to claim 1, further comprising: a first biasing member configured to bias the first holding member toward the other of the first guide members; a second biasing member configured to bias the second holding member toward the other of the second guide members; and a third biasing member configured to bias the third holding member toward the other of the third guide members.

12. The optical device according to claim 1, wherein the first biasing member is disposed in the first region, the second biasing member is disposed in the second region, and the third biasing member is disposed in the third region.

13. The optical device according to claim 1, further comprising: a first driving unit configured to move the first holding member; a second driving unit configured to move the second holding member; a third driving unit configured to move the third holding member; and a base member configured to hold the first driving unit, the second driving unit, and the third driving unit.

14. The base member includes a first engaging portion, a second engaging portion, and a third engaging portion that are arranged in the circumferential direction when viewed from the optical axis direction and engage with other members.

15. The optical device according to claim 1, wherein when viewed from the optical axis direction, the first region is between the first engaging portion and the second engaging portion, the second region is between the second engaging portion and the third engaging portion, and the third region is between the third engaging portion and the first engaging portion.

11. It has a base member that holds the first holding member, the second holding member, and the third holding member. The base member includes a first engaging portion, a second engaging portion, and a third engaging portion that are arranged in the circumferential direction when viewed from the optical axis direction and engage with other members. When viewed from the optical axis direction, the first region is between the first engaging portion and the second engaging portion, the second region is between the second engaging portion and the third engaging portion, and the third region is between the third engaging portion and the first engaging portion. The optical device according to claim 1, characterized in that.

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

13. An imaging device, comprising: the optical device according to any one of claims 1 to 12; and an imaging element that receives light from the optical device.

Images