Lens device and imaging device
The lens device design addresses the issue of scale length and flexible circuit board entry by using a groove and projection configuration to maintain compact size and prevent optical path interference.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- CANON KK
- Filing Date
- 2024-11-21
- Publication Date
- 2026-06-02
AI Technical Summary
The existing lens devices face challenges in managing the length of the scale along the optical axis, leading to potential enlargement of the holding frame and risk of the flexible printed circuit board entering the optical path due to the movement of the holding frame.
A lens device design that includes a fixed cylinder with a groove and a retaining frame projection, positioning the flexible wiring board to avoid overlap with the groove, and housing it outside the fixed cylinder to prevent entry into the optical path.
Prevents the flexible wiring board from entering the optical path and reduces the overall size of the retaining frame along the optical axis, ensuring smooth operation and preventing interference with other structures.
Smart Images
Figure 2026090066000001_ABST
Abstract
Description
Technical Field
[0001] The disclosure of this specification relates to a lens device and an imaging device.
Background Art
[0002] Conventionally, a lens device including a holding frame that holds a lens and a fixed cylinder that holds the holding frame movably in a direction along the optical axis has been known. In such a lens device, a sensor for detecting the position of the holding frame in the direction along the optical axis is provided.
[0003] Patent Document 1 discloses a lens device that detects the position of a holding frame by providing an optical scale on the holding frame and detecting a change in light amount with an optical sensor fixed to a fixed cylinder.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, in the configuration described in Patent Document 1, the length of the scale provided on the holding frame in the direction along the optical axis needs to be at least equal to the total movement distance that the holding frame (moving frame) can move. Therefore, when the movement distance of the holding frame becomes long, at least a part of the holding frame may be enlarged in the direction along the optical axis.
[0006] In order to suppress the enlargement of the holding frame, if the scale is provided on the fixed cylinder and the sensor is provided on the holding frame, a flexible printed circuit board (FPC) for transmitting the signal of the sensor to a control board provided on the fixed cylinder is provided in the lens device. Since the holding frame moves in the direction along the optical axis with respect to the fixed cylinder, there is a risk that the excess of the flexible printed circuit board disposed between the holding frame and the fixed cylinder may enter the optical path. [Means for solving the problem]
[0007] A lens device according to an embodiment of the present invention comprises a retaining frame for holding a lens, a fixed cylinder for holding the retaining frame so as to be movable in a direction along the optical axis of the lens, a driving means for driving the retaining frame in a direction along the optical axis, a position detection means including a detected portion provided on the fixed cylinder and a detection portion provided on the retaining frame, and a flexible wiring board connecting the detection portion and a control unit provided on the fixed cylinder, wherein the fixed cylinder has a cylindrical portion that covers at least a part of the outer diameter of the retaining frame and a housing portion that houses the flexible wiring board in a direction along the optical axis, the fixed cylinder has a groove formed therein that penetrates from the inside of the cylindrical portion to the housing portion, the retaining frame has a projection inserted into the groove, the detection portion is fixed to the projection, the detected portion is housed in the housing portion, and at least a part of the flexible wiring board that extends beyond the projection in a direction along the optical axis is positioned so as not to overlap with the groove when viewed from the radial direction of the fixed cylinder. [Effects of the Invention]
[0008] In a lens device, it is possible to realize a lens device that prevents the flexible wiring board, which is connected to a detection unit provided on a retaining frame that is movable in the direction along the optical axis, from entering the inside of the fixed cylinder (in the optical path). [Brief explanation of the drawing]
[0009] [Figure 1] This diagram shows the configuration of the lens device in Example 1. [Figure 2] This figure shows the FPC housing section at the first zoom end of Example 1. [Figure 3] This is a view of the lens device from arrow A shown in Figure 2. [Figure 4] This figure shows the BB cross-section as shown in Figure 2. [Figure 5] This figure shows the FPC housing at the second zoom end, opposite to Figure 2. [Figure 6]This figure shows the FPC housing section at the first zoom end of Example 2. [Figure 7] This figure shows the EE cross-section as shown in Figure 6. [Figure 8] This figure shows the FPC housing at the second zoom end, opposite to Figure 6. [Figure 9] This diagram shows a modified example of a flexible circuit board. [Figure 10] This is a diagram showing the FPC housing section of Example 3. [Figure 11] This figure shows the FF cross-section shown in Figure 10. [Figure 12] This is a schematic diagram showing an imaging device. [Modes for carrying out the invention]
[0010] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same reference numeral is used for the same component, and redundant descriptions are omitted. This embodiment relates to a lens device having a detection unit in a holding frame that holds a lens, and a scale on a fixed cylinder that holds the holding frame so as to be movable in a direction along the optical axis.
[0011] (Example 1) The lens device L of Embodiment 1 of the present invention will be described with reference to Figures 1 to 5. Here, Figure 1 is a diagram showing the configuration of the lens device, Figure 2 is a diagram showing the FPC housing at the first zoom end, Figure 3 is a view of the lens device from arrow A shown in Figure 2, and Figure 4 is a diagram showing the BB cross section shown in Figure 2. Figure 5 is a diagram showing the FPC housing when the moving group is positioned at the opposite second zoom end from the state at the first zoom end shown in Figure 2.
[0012] FIG. 1 is a diagram showing the configuration of the lens device L. The lens device L includes a lens body 100. The lens device L includes an exterior 200 and an exterior 300 that cover at least the lens body 100. The lens body 100 includes a focus unit 1 in which at least some lens groups move for focusing, and a zoom unit 2 that includes a plurality of lens groups that move for zooming. Further, the lens body 100 includes an aperture stop 3 for adjusting the amount of light, an extender unit 4 for switching the focal length range, and a relay unit 5 that includes an imaging optical system.
[0013] The zoom unit 2 has a fixed cylinder 6 (fixed lens barrel), holding frames 7, 8, and 9 that hold lens groups, and a cam cylinder 10 that is rotatably supported around a cam shaft C parallel to the optical axis P. The holding frames 7, 8, and 9 each include a cam follower 7a, a cam follower 8a, and a cam follower 9a. The cam followers can each be cylindrical. Further, the cam followers 7a, 8a, and 9a are respectively engaged with cams 10a, 10b, and 10c formed on the cam cylinder 10. For example, the cam follower has a cylindrical shape and the cam has a groove shape. Further, the holding frames 7, 8, and 9 each include a guide follower (not shown), and the guide followers are respectively engaged with a straight guide (not shown) formed on the fixed cylinder 6 along the optical axis P. The cam cylinder 10 is rotationally driven around the cam shaft C by a drive unit or the like, and as a result, the holding frames 7, 8, and 9 are each driven in a direction along the optical axis P (optical axis direction), and the focal length of the lens device L changes. Thus, each holding frame is a moving frame (moving member) that moves with respect to the fixed cylinder.
[0014] As shown in FIGS. 2 to 4, the fixed cylinder 6 has a cylindrical portion 6a that covers at least a part of the outer diameters of the holding frames 7, 8, and 9. Further, the fixed cylinder 6 has a groove 6b that extends along the optical axis P and penetrates from the inside to the outside of the cylindrical portion 6a, and a wall 6c is formed on the outside of the cylindrical portion 6a so as to surround the groove 6b. A lid 11 is fixed to the outside of the wall 6c of the fixed cylinder 6 so as to cover the opening of the wall 6c. A protrusion 7b inserted into the groove 6b of the fixed cylinder 6 is formed on the holding frame 7.
[0015] In the space 6d formed by the wall 6c of the fixed cylinder 6 and the lid 11, a position detection means 12 for detecting the position of the holding frame 7 in the optical axis direction and an FPC 15 (flexible printed circuit board) are accommodated. The position detection means 12 of the first embodiment includes a sensor 13 as a detection part and a scale 14 as a detected part. Further, the FPC 15 is provided with an FPC fixing part 15a and an FPC extending part 15b extending in the optical axis direction from the FPC fixing part 15a, and the FPC fixing part 15a is fixed to the protruding part 7b of the holding frame 7 with a screw 16. Here, the space 6d for accommodating the FPC 15 (flexible printed circuit board) in the direction along the optical axis is called an accommodating part.
[0016] With this configuration, in the state where the lid 11 is removed, the FPC 15 can be attached to the holding frame 7 from the outside of the fixed cylinder 6. Therefore, in the state where the position detection means 12 and the FPC 15 are removed, each adjustment operation (optical adjustment) such as the position and orientation of each optical system of the lens device L can be performed, so fixing the FPC 15 to the holding frame 7 does not impair the workability of the optical adjustment.
[0017] The sensor 13 is arranged on the FPC fixing part 15a of the FPC 15, and the scale 14 is fixed by adhesion to the surface of the lid 11 facing the sensor 13. The FPC extending part 15b is connected to the control board 17 (control part) through a notch 6e formed in the wall 6c of the fixed cylinder 6. With this configuration, the detection signal of the sensor 13 is communicated to the control board 17 (control part) via the FPC 15. In addition, in order to prevent foreign matter from entering from the notch 6e and adhering to the sensor 13 and the scale 14 or entering the inside of the cylindrical part 6a of the fixed cylinder 6, the notch 6e may be sealed with a sealing material or the like.
[0018] When the holding frame 7 is driven along the optical axis P, the light projected from the light emitting part of the sensor 13 is reflected by the scale 14, and by receiving the reflected light by the light receiving part of the sensor 13, the position of the holding frame 7 in the direction along the optical axis can be discriminated.
[0019] As shown in Figures 3 and 4, the portion of the FPC extension 15b that extends beyond the projection end face 7c of the retaining frame 7 is positioned so as not to overlap with the groove 6b. In other words, as shown in Figure 3, when the groove 6b is viewed from the radial direction of the fixed cylinder 6, at least a portion of the FPC extension 15b of the FPC 15 is positioned so as not to overlap with the groove 6b. Therefore, even when the excess portion of the FPC extension 15b becomes large, as shown in Figure 5, it is possible to prevent the FPC extension 15b from falling into the groove 6b.
[0020] As described above, in the lens device of Embodiment 1, a detection unit is provided on the retaining frame, and a housing unit for arranging the flexible wiring board is provided on the outside of the fixed cylinder. Therefore, it is possible to suppress the increase in size of the retaining frame along the optical axis. In addition, the structure is such that the flexible wiring board does not fall out into the groove connecting the housing unit for the flexible wiring board and the inside of the fixed cylinder. Therefore, it is possible to suppress the excess portion of the flexible wiring board entering the optical path of the lens device and the flexible wiring board interfering with other retaining frames or structures.
[0021] (Example 2) The lens device of Embodiment 2 of the present invention will be described with reference to Figures 6 to 8. Here, Figure 6 shows the FPC housing at the first zoom end, and Figure 7 shows the EE cross-section shown in Figure 6. Figure 8 shows the FPC housing when the moving group is positioned at the second zoom end, opposite to the state at the first zoom end shown in Figure 6.
[0022] As shown in Figures 6 to 8, the fixed tube 20 (fixed lens barrel) has a cylindrical portion 20a that covers at least a portion of the outer diameter of the retaining frame 7. The fixed tube 20 also has a groove 20b that extends along the optical axis P and penetrates from the inside to the outside of the cylindrical portion 20a, and a wall 20c is formed on the outside of the cylindrical portion 20a so as to surround the groove 20b. A cover 21 is fixed to the outside of the wall 20c of the fixed tube 20 so as to cover the opening of the groove 20b. The retaining frame 7 has a projection 7b that is inserted into the groove 20b of the fixed tube 20.
[0023] The space 20d formed by the wall 20c and lid 21 of the fixed cylinder 20 houses a position detection means 12 for detecting the position of the holding frame 7 in the optical axis direction, and an FPC 22 (flexible printed circuit board). The position detection means 12 in Embodiment 2 includes a sensor 13 as a detection unit and a scale 14 as a detected unit. The FPC 22 is provided with an FPC fixing unit 22a and an FPC extension unit 22b extending from the FPC fixing unit 22a in the optical axis direction, and the FPC fixing unit 22a is fixed to a projection 7b of the holding frame 7. Here, the space 20d that houses the FPC 22 (flexible printed circuit board) in the direction along the optical axis will be called the housing unit.
[0024] A regulating member 23 is fixed to the surface of the lid 21 facing the FPC 22, regulating the position of the outer bent portion 22c of the FPC extension portion 22b of the FPC 22. The sensor 13 is positioned on the FPC fixing portion 22a of the FPC 22, and the scale 14 is fixed by adhesive to the surface of the lid 21 facing the sensor 13. When light rays entering the FPC 22 from inside the fixing cylinder 20 through the groove 20b are reflected by the inner surface 22e of the FPC extension portion 22b and enter the inside of the fixing cylinder 20 again, there is a risk of ghosting occurring in the image obtained through the lens device L. To prevent ghosting, it is desirable to apply light-shielding means such as coating the inner surface 22e of the FPC extension portion 22b with light-shielding paint or attaching a light-shielding sheet.
[0025] As shown in Figure 6, the inner bent portion 22d of the FPC 22 is positioned to engage with the end portion 20f of the groove 20b. In other words, when the groove 20b is viewed from the radial direction of the fixed cylinder 20, at least a portion of the FPC extension portion 22b of the FPC 22 is positioned so as not to overlap with the groove 20b. Therefore, even when the excess portion of the FPC extension portion 22b becomes large, as shown in Figure 8, the FPC extension portion 22b is accommodated within the space 20d, thus preventing the FPC extension portion 22b from falling into the groove 20b.
[0026] As a modified example of the flexible printed circuit board of Example 2, a structure in which a wide portion 24a, wider than the width of the groove 20b, is provided in a part of the FPC 24 may also be used, as shown in Figure 9. By using the FPC 24 shown in Figure 9, it is possible to prevent the FPC extended portion 24b from falling into the groove 20b.
[0027] Thus, in the lens device of Embodiment 2, a detection unit is provided on the retaining frame, and a housing unit for arranging the flexible wiring board is provided on the outside of the fixed cylinder. Therefore, it is possible to suppress the increase in size of the retaining frame along the optical axis. In addition, the structure is such that the flexible wiring board does not fall out into the groove connecting the housing unit for the flexible wiring board and the inside of the fixed cylinder. Therefore, it is possible to suppress the excess portion of the flexible wiring board from entering the optical path of the lens device and the flexible wiring board from interfering with other retaining frames or structures.
[0028] (Example 3) The lens device of Embodiment 3 of the present invention will be described with reference to Figures 10 and 11. Here, Figure 10 is a diagram showing the FPC housing section according to Embodiment 3, and Figure 11 is a diagram showing the FF cross-section shown in Figure 10.
[0029] As shown in Figures 10 and 11, the fixed tube 30 (fixed lens barrel) has a cylindrical portion 30a that covers at least a portion of the outer diameter of the retaining frame 7. The fixed tube 30 also has a groove 30b that extends along the optical axis P and penetrates from the inside to the outside of the cylindrical portion 30a, and a wall 30c is formed on the outside of the cylindrical portion 30a so as to surround the groove 30b. A cover 31 is fixed to the outside of the wall 30c of the fixed tube 30 so as to cover the opening of the groove 20b. The retaining frame 7 has a projection 7b that is inserted into the groove 30b of the fixed tube 30.
[0030] The space 30d formed by the wall 30c and lid 31 of the fixed cylinder 30 houses a position detection means 12 for detecting the optical axis position of the retaining frame 7 and an FPC 32 (flexible printed circuit board). The position detection means 12 of Embodiment 3 includes a sensor 13 as a detection unit and a scale 14 as a detected unit. The FPC 32 is fixed to the projection 7b of the retaining frame 7 via an FPC support plate 33. The sensor 13 is located on the FPC fixing part 32a of the FPC 32, and the scale 14 is located on the inner wall surface of the wall 30c of the fixed cylinder 30.
[0031] As shown in Figure 11, the bent portion 32c of the FPC extension portion 32b of the FPC 32 is positioned to intersect with the edge of the groove 30b formed in the fixed cylinder 30 in a direction along the optical axis. In this case, a part of the bent portion 32c is positioned to overlap with the groove 30b, but the FPC extension portion 32b connecting the bent portion 32c and the fixed portion 32a is positioned not to overlap with the groove 30b. In other words, as shown in Figure 11, when the groove 30b is viewed from the radial direction of the fixed cylinder 30, at least a part of the FPC extension portion 32b of the FPC 32 is positioned not to overlap with the groove 30b. Therefore, it is possible to prevent the FPC extension portion 32b from falling into the groove 30b of the fixed cylinder 30.
[0032] Thus, according to the lens device of Embodiment 3, a detection unit is provided in the retaining frame, and a housing unit for arranging the flexible wiring board is provided on the outside of the fixed cylinder. Therefore, it is possible to suppress the increase in size of the retaining frame along the optical axis. Furthermore, it is possible to suppress the flexible wiring board from entering the optical path of the flexible wiring board in the groove connecting the housing unit and the inside of the fixed cylinder, and to suppress the flexible wiring board from interfering with other retaining frames or structures.
[0033] (Other examples) In each of the above embodiments, an optical scale was used as the detected part of the position detection means for the holding frame, and an optical sensor that reads the optical scale was used as the detection part. As for the position detection means, a magnetic sensor may be used as the detection part, and a magnetic scale may be used as the detected part. In this way, similar effects can be obtained even if a position detection means using other detection methods is used.
[0034] Furthermore, in the above embodiments, the scale to be detected is described as a separate component from the fixed cylinder, attached to the lid or the wall of the fixed cylinder. However, the scale may be integrally formed with the fixed cylinder.
[0035] Furthermore, the placement of the sensor as the detection unit is not limited to mounting it on the flexible wiring board; it may also be mounted on a substrate connected to the flexible wiring board. In this case, the detection unit is fixed to the retaining frame by fixing the substrate on which the sensor is mounted to a protrusion on the retaining frame.
[0036] Furthermore, in each of the above embodiments, the object whose position in the direction along the optical axis is detected was described as a single holding frame 7, but a configuration in which the positions of multiple holding frames are detected is also possible. In this case, sensors as detection units included in the position detection means are attached to the other holding frames 8, holding frames 9, etc. When position detection means are provided on multiple holding frames, it is desirable to take measures against false detection by providing light-shielding members that block light from the light-emitting parts of sensors placed on adjacent holding frames. In addition, the scales that are to be detected, which are provided on the fixed cylinder, may be provided corresponding to each detection means, or they may share a single scale.
[0037] (Imaging device) Figure 12 is a schematic diagram of the imaging device 400. As shown in Figure 12, the imaging device 400 comprises a lens device L and a camera body 500. The camera body 500 comprises an image sensor 600. The image sensor 600 receives light from the lens device L. The lens device L comprises a lens body 100, a retaining frame 7 that holds at least a portion of the lens of the lens body 100, and a fixing cylinder 6 that holds the retaining frame 7 so as to be movable in a direction along the optical axis. The configuration of the retaining frame 7 and the fixing cylinder is as described in each embodiment above.
[0038] The lens device L is attached to the camera body 500. The lens device L may be detachable from the camera body 500, or it may be integrated with the camera body 500.
[0039] The disclosure of embodiments of the present invention includes the following configurations.
[0040] (Composition 1) A retaining frame that holds the lens, A fixed cylinder that holds the retaining frame so as to be movable in a direction along the optical axis of the lens, A driving means for driving the holding frame in a direction along the optical axis, A position detection means including a detection unit provided on the fixed cylinder and a detection unit provided on the holding frame, In a lens device comprising a flexible wiring board connecting the detection unit and the control unit provided on the fixed cylinder, The fixing cylinder has a cylindrical portion that covers at least a part of the outer diameter of the retaining frame and a housing portion that houses the flexible wiring board in a direction along the optical axis. The aforementioned fixing cylinder has a groove formed that penetrates from the inside of the cylindrical portion to the housing portion. The retaining frame has a projection that is inserted into the groove, The detection unit is fixed to the projection, The detected unit is housed in the housing unit, A lens device characterized in that at least a portion of the flexible wiring plate extending in the direction along the optical axis from the projection is positioned so as not to overlap with the groove when the groove is viewed from the radial direction of the fixed cylinder.
[0041] (Configuration 2) The lens device according to configuration 1, characterized in that the bent portion of the flexible wiring board is positioned so as not to overlap with the groove.
[0042] (Composition 3) The lens device according to configuration 1 or 2, characterized in that the flexible wiring board intersects with the edge of the groove extending in a direction along the optical axis.
[0043] (Composition 4) The system comprises a plurality of the aforementioned holding frames and a plurality of the aforementioned detection units provided on each of the holding frames, The lens device according to any one of configurations 1 to 3, characterized in that the plurality of detection units share one of the detected units.
[0044] (Composition 5) The lens device according to any one of configurations 1 to 4, characterized in that the detection unit is arranged on the flexible wiring board and the flexible wiring board is fixed to the projection.
[0045] (Composition 6) The lens device according to any one of configurations 1 to 4, characterized in that the detection unit is arranged on a substrate connected to the flexible wiring board.
[0046] (Composition 7) The lens device according to any one of configurations 1 to 6, characterized in that the detected part is an optical scale and the detection part is an optical sensor.
[0047] (Composition 8) The lens device according to any one of configurations 1 to 6, characterized in that the detected part is a magnetic scale and the detection part is a magnetic sensor.
[0048] (Composition 9) The lens device according to any one of configurations 1 to 8, characterized in that the position detection means detects the position of the retaining frame in a direction along the optical axis with respect to the fixed cylinder.
[0049] (Composition 10) The lens device according to any one of configurations 1 to 9, characterized in that at least a portion of the housing portion is provided on the outside of the cylindrical portion.
[0050] (Composition 11) The lens device according to any one of configurations 1 to 10, characterized in that the detected portion is integrally formed with the fixed cylinder.
[0051] (Composition 12) The lens device according to any one of configurations 1 to 10, characterized in that the detected part is a scale provided on a separate member from the fixed cylinder.
[0052] (Composition 13) A lens device according to any of configurations 1 to 12, An imaging device characterized by comprising a camera body having an image sensor that receives light from the aforementioned lens device.
[0053] Although 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 its gist. [Explanation of Symbols]
[0054] 6 Fixed tube 7 Holding slots 12 Position detection means 13. Sensor (detection unit) 14. Scale (detected area) 15. FPC (Flexible Printed Circuit Board) L Lens Device
Claims
1. A retaining frame that holds the lens, A fixed cylinder that holds the retaining frame so as to be movable in a direction along the optical axis of the lens, A driving means for driving the holding frame in a direction along the optical axis, A position detection means including a detection unit provided on the fixed cylinder and a detection unit provided on the holding frame, In a lens device comprising a flexible wiring board connecting the detection unit and the control unit provided on the fixed cylinder, The fixing cylinder has a cylindrical portion that covers at least a part of the outer diameter of the retaining frame and a housing portion that houses the flexible wiring board in a direction along the optical axis. The aforementioned fixing cylinder has a groove formed that penetrates from the inside of the cylindrical portion to the housing portion. The retaining frame has a projection that is inserted into the groove, The detection unit is fixed to the projection, The detected unit is housed in the housing unit, A lens device characterized in that at least a portion of the flexible wiring plate extending in the direction along the optical axis from the projection is positioned so as not to overlap with the groove when the groove is viewed from the radial direction of the fixed cylinder.
2. The lens device according to claim 1, characterized in that the bent portion of the flexible wiring board is positioned so as not to overlap with the groove.
3. The lens device according to claim 1, characterized in that the flexible wiring board intersects with the edge of the groove extending in a direction along the optical axis.
4. The system comprises a plurality of the aforementioned holding frames and a plurality of the aforementioned detection units provided on each of the holding frames, The lens device according to claim 1, characterized in that the plurality of detection units share one of the detected units.
5. The lens device according to claim 1, characterized in that the detection unit is arranged on the flexible wiring board and the flexible wiring board is fixed to the projection.
6. The lens device according to claim 1, characterized in that the detection unit is arranged on a substrate connected to the flexible wiring board.
7. The lens device according to claim 1, characterized in that the detected part is an optical scale and the detection part is an optical sensor.
8. The lens device according to claim 1, characterized in that the detected part is a magnetic scale and the detection part is a magnetic sensor.
9. The lens device according to claim 1, characterized in that the position detection means detects the position of the retaining frame in a direction along the optical axis with respect to the fixed cylinder.
10. The lens device according to claim 1, characterized in that at least a portion of the housing portion is provided on the outside of the cylindrical portion.
11. The lens device according to claim 1, characterized in that the detected portion is integrally formed with the fixed cylinder.
12. The lens device according to claim 1, characterized in that the detected part is a scale provided on a separate member from the fixed cylinder.
13. A lens device according to any one of claims 1 to 12, An imaging device characterized by comprising a camera body having an image sensor that receives light from the aforementioned lens device.