Optical devices and imaging devices

Abstract

To provide an optical device that is advantageous in adjustment of optical characteristics and size reduction.SOLUTION: A lens device 1 has: a stationary barrel 8; a movable barrel 5 that is arranged inside the stationary barrel 8 and holds a second lens 2b; a conversion mechanism that moves the movable barrel 5 along an optical axis O through rotation of the movable barrel 5 around the optical axis O; and an operation member 9 that is arranged through the stationary barrel 8 and rotationally operated. The operation member 9 has a rotational shaft part 9a including a rotational axis A1 of the rotational operation, and an eccentric shaft part 9b that is eccentric from the rotational axis A1. The eccentric shaft part 9b includes an engagement part 9e that is engaged with a straight groove 5a formed in the movable barrel 5 along the optical axis O. In a direction orthogonal to the rotational axis A1, at least part of the engagement part 9e is outside the rotational shaft part 9a. The operation member 9 is rotated to cause the engagement part 9e to slide on the movable barrel 5 along the straight groove 5a and rotate the movable barrel 5 around the optical axis O, and cause the conversion mechanism to move the movable barrel 5 along the optical axis O.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Since components of an optical device such as a lens device have dimensional errors, the optical characteristics of the optical device may deviate from the design values. For this reason, a lens device is known in which the position of the focal plane can be adjusted by, for example, adjusting the position of the movable final lens group in the optical axis direction (so-called flange back adjustment).

[0003] Patent Document 1 discloses a flange focal length adjustment mechanism in which rotation around the optical axis of a movable barrel is converted into movement in the optical axis direction of the movable barrel by a rotation-to-linear conversion mechanism such as a helicoid mechanism. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6415425 Summary of the Invention [Problem to be solved by the invention]

[0005] In the flange back adjustment mechanism of Patent Document 1, if the distance between the rotation axis and eccentric axis of the operating unit is increased in order to increase the amount of movement of the movable barrel in the optical axis direction, the operating unit becomes larger, and therefore it is necessary to increase the diameter of the circular hole in the fixed barrel through which the operating unit passes.

[0006] An object of the present invention is to provide an optical device that is advantageous in terms of, for example, adjusting optical characteristics and being compact. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides an optical device having a fixed barrel, a movable barrel that is disposed inside the fixed barrel and that holds an optical element, a mechanism that moves the movable barrel along an optical axis by rotating the movable barrel around the optical axis, and an operating member that is disposed through the fixed barrel and that is operated to rotate, wherein the operating member has a rotation shaft portion that includes a rotation axis for the rotation operation, and an eccentric portion that is eccentric from the rotation shaft, and the eccentric portion includes an engaging portion that engages with a guide portion formed on the movable barrel along the optical axis, and in a direction perpendicular to the rotation shaft: a distance from the rotary shaft to the outermost surface of the engagement portion is greater than a radius of the rotary shaft portion, and a non-circular hole through which the operating member passes is formed in the fixed cylinder; By rotating the operating member, the engaging portion slides along the guide portion onto the movable barrel and rotates the movable barrel around the optical axis, and the mechanism moves the movable barrel along the optical axis. [Effects of the Invention]

[0008] According to the present invention, for example, it is possible to provide an optical device that is advantageous in terms of adjustment of optical characteristics and compact size. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a lens device 1 according to an embodiment. [Figure 2] FIG. 2 is a perspective view of a flange focal length adjustment section of the lens device 1 of the embodiment. [Figure 3] 1 is an exploded perspective view showing a state in which an operating member 9 of the embodiment is inserted into a fixed barrel 8. FIG. [Figure 4] FIG. 4 is an enlarged view of a hole in the embodiment. [Figure 5] FIG. 4 is an enlarged cross-sectional view of a flange back adjustment portion of the embodiment. [Figure 6] FIG. 2 is an enlarged view of the operating member 9 of the embodiment. [Figure 7] FIG. 10 is an enlarged cross-sectional view of a flange back adjustment portion of a modified example of the embodiment. [Figure 8] FIG. 10 is an enlarged view of a hole in a modified example of the embodiment. [Figure 9] FIG. 1 is a schematic diagram illustrating an example of the configuration of an imaging device. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Example) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A lens device 1 (optical device) according to an embodiment of the present invention will now be described with reference to the drawings. Figure 1 shows a cross-sectional view of the lens device 1 according to the embodiment.

[0011] The lens device 1 is provided with a plurality of optical elements, which are composed of a first lens 2a, a second lens 2b, and a third lens 2c. The first lens 2a, which is a front fixed group, is fixed to a front fixed barrel 3, the second lens 2b, which is an object to be adjusted by a flange back adjustment unit (described later), is fixed to a movable barrel 5, and the third lens 2c, which is a relay group, is fixed to a rear fixed barrel 6.

[0012] A lens mount 7 is provided at the end of the rear fixed barrel 6, which is connected to a mount unit of an imaging device (not shown) during shooting. A fixed barrel 8 is provided between the front fixed barrel 3 and the rear fixed barrel 6. A flange focal length adjustment unit is provided on the fixed barrel 8. The front fixed barrel 3 and the fixed barrel 8 are connected by a plurality of screws (not shown). The fixed barrel 8 and the rear fixed barrel 6 are connected by a plurality of screws 10. A movable barrel 5 that holds the second lens 2b is disposed inside the fixed barrel 8.

[0013] The first lens 2a is fixed to the front fixed barrel 3 by fastening a first retaining ring 11a to a threaded portion formed on the front fixed barrel 3. The second lens 2b is fixed to the movable barrel 5 by fastening a second retaining ring 11b to a threaded portion formed on the movable barrel 5. The third lens 2c is fixed to the rear fixed barrel 6 by fastening a third retaining ring 11c to a threaded portion formed on the rear fixed barrel 6. Although explanation of the lens device 1 will be omitted in the examples, it may be configured so that focus adjustment, magnification variation, and light intensity adjustment are possible using a structure not shown.

[0014] The flange focal length adjustment unit will be described with reference to FIGS. 1 and 2. FIG. 2 is a perspective view of the flange focal length adjustment unit of the lens device 1. Flange focal length adjustment is performed by rotating an operation member 9, which will be described later. The operation member 9 is normally covered by a rubber cap 12 (second cap member) provided on a cover member 13. The cover member 13 is provided on the outer circumferential surface of the fixed barrel 8, and is provided so that the operation member 9 and a lock screw 14 (fixing member) are covered by fitting the rubber cap 12 into the cover member 13. The rubber cap 12 prevents the operation member 9 and the lock screw 14 from being exposed to the exterior. The cover member 13 is made of a material such as resin or metal, and is fixed to the outer circumferential surface of the fixed barrel 8 with two screws 15. The rubber cap 12 is an elastic member such as rubber or resin, and is fixed by being press-fitted into the cover member 13. When the rubber cap 12 is removed, the operation member 9 and the lock screw 14 are exposed to the exterior.

[0015] Next, the movable barrel 5, fixed barrel 8, operating member 9 and cap member 16 (first cap member) will be described with reference to Figures 3 to 5. Figure 3 is an exploded perspective view showing the state in which the operating member 9 is inserted into the fixed barrel 8. Figure 4 is an enlarged view of a non-circular hole (hole) formed in the fixed barrel 8. Figure 5 is an enlarged cross-sectional view of the flange back adjustment portion.

[0016] The movable barrel 5 has an approximately cylindrical shape, and a second pressing ring 11b that fixes the second lens 2b is screwed onto its inner periphery, and a male helicoid screw portion 5b with multiple threads and a linear groove 5a (guide portion) are formed on its outer periphery along the optical axis direction H.

[0017] A non-circular hole through which the operating member 9 passes is formed in the fixed barrel 8, penetrating from the outer peripheral surface to the inner peripheral surface. The non-circular hole is formed by an arc portion 8a having a partial arc and a recess portion 8c connected to the arc portion 8a, and its overall shape is approximately keyhole-shaped. A sliding surface 8b is formed on a part of the arc surface of the arc portion 8a, and the rotating shaft portion 9a of the operating member 9 is fitted onto the sliding surface 8b, allowing the rotating shaft portion 9a to slide smoothly on the sliding surface 8b and preventing the rotating shaft portion 9a from tilting. The recess portion 8c is formed so that the eccentric shaft portion 9b (eccentric portion) of the operating member 9 can be inserted therethrough. The recess portion 8c is formed from the center of the rotating shaft portion 9a of the arc portion 8a along the optical axis direction H. In other words, the longitudinal direction of the non-circular hole is along the optical axis direction H. The non-circular hole portion has a sliding surface 8b and a relief portion 8c integrally formed to have a generally keyhole shape, which allows the operating member 9 to be inserted into the fixed barrel 8. In this way, the operating member 9 is disposed so as to pass through the fixed barrel 8, and can be rotated.

[0018] The operating member 9 is composed of a rotation shaft portion 9a including a rotation axis A1 for rotation operation, an eccentric shaft portion 9b eccentric from the rotation axis A1, a groove portion 9c, a disk portion 9d, and an engagement portion 9e. Furthermore, an arc groove 9f is formed through the disk portion 9d. The rotation shaft portion 9a is coaxial with the rotation axis A1, and the eccentric shaft portion 9b is parallel to the rotation shaft portion 9a and protrudes eccentrically from the rotation axis A1. That is, the eccentric shaft portion 9b extends in a direction closer to the optical axis O than the rotation shaft portion 9a. An engagement portion 9e is formed at the tip of the eccentric shaft portion 9b. The engagement portion 9e engages with a linear groove 5a formed on the outer periphery of the movable barrel 5 along the optical axis O. The engagement portion 9e engaging with the linear groove 5a includes a spherical surface that contacts the linear groove 5a and is approximately spherical in shape at least in the area that contacts the wall of the linear groove 5a. Furthermore, at least a portion of the engagement portion 9e is located outside the rotation shaft portion 9a in a direction perpendicular to the rotation axis A1. The distance L2 from the rotation axis A1 to the outermost surface of the engagement portion 9e is longer than the radius L1 of the rotation shaft portion 9a, and this shape of the operating member 9 ensures a larger flange focal length adjustment amount than before, without increasing the size of the lens device 1.

[0019] The groove 9c is a groove into which a tool such as a flat-head screwdriver is inserted to rotate the operation when adjusting the optical performance (when adjusting the flange back). The disk portion 9d abuts against the flat surface portion 8d on the outer periphery of the fixed barrel 8, and the operation member 9 is disposed on the fixed barrel 8 so as to be able to rotate smoothly around the rotation axis A1 that is perpendicular to the optical axis O.

[0020] Then, after the eccentric shaft portion 9b of the operating member 9 is inserted into the recessed portion 8c of the fixed barrel 8, the cap member 16 is placed in the non-circular hole. More specifically, the cap member 16 is inserted into the recessed portion 8c. The cap member 16 is fixed to the fixed barrel 8 by bonding with an adhesive, bonding with double-sided tape, or by press-fitting. The cap member 16 is made of a metal, resin, or rubber material. The cap member 16 is formed with an arc-shaped sliding surface 16a on which the rotating shaft portion 9a of the operating member 9 slides.

[0021] The female helicoid 17 is connected to the front fixed barrel 3 by a plurality of screws 18. The female helicoid 17 has a female helicoid screw portion 17a with multiple threads formed on its inner periphery. The male helicoid screw portion 5b of the movable barrel 5 is screwed into the female helicoid screw portion 17a, and the movable barrel 5 moves along the optical axis O as the movable barrel 5 rotates around the optical axis O due to a conversion mechanism (mechanism) that converts the rotational movement of the helicoid mechanism into linear movement. The conversion mechanism may be a cam mechanism or a helicoid mechanism.

[0022] 6 is an enlarged view of the operating member 9 attached to the fixed barrel 8. An arc groove 9f having an arc of approximately 180° is formed in the disk portion 9d and penetrates the disk portion 9d. A lock screw 14 is inserted into the arc groove 9f and threaded into a screw hole 8e of the fixed barrel 8 (see FIG. 4).

[0023] The adjustment reference state, in which the flange focal length adjustment unit is positioned approximately in the center of the adjustment range, is a state in which the rotation axis A1 of the rotation shaft portion 9a and the central axis A2 of the eccentric shaft portion 9b are furthest apart in the optical axis direction H (see, for example, FIG. 5). The lock screw 14 has a groove 14a formed in its head, into which a tool such as a flat-head screwdriver is inserted to rotate the lock screw 14. When the lock screw 14 is rotated in the feed direction toward the optical axis O, the disk portion 9d of the operating member 9 is sandwiched between the flat portion 8d on the outer periphery of the fixed barrel 8 and the head of the lock screw 14. The lock screw 14 is threadedly engaged with a threaded hole 8e formed in the fixed barrel 8, thereby fixing the operating member 9 to the fixed barrel 8 so that the operating member 9 cannot be rotated.

[0024] A method for adjusting the flange focal length in the lens device 1 configured as above will be described below with reference to FIGS. 2, 5 and 6. FIG.

[0025] First, remove the rubber cap 12 of the flange back adjustment section and loosen the exposed lock screw 14 using a tool such as a flathead screwdriver. Loosening the lock screw 14 releases the hold on the disk portion 9d of the operating member 9, allowing the operating member 9 to be rotated.

[0026] Next, using a tool such as a flathead screwdriver, the groove 9c of the operating member 9 is rotated. The rotation range is limited by the abutment of the lock screw 14 with the end of the arcuate groove 9f, so it is limited to a range of approximately 90° clockwise and counterclockwise from the adjustment reference state. By rotating the operating member 9, the engagement portion 9e slides along the linear groove 5a on the movable barrel 5 and rotates the movable barrel 5 around the optical axis O.

[0027] The conversion mechanism of the helicoid mechanism converts this rotation into linear motion, moving the movable barrel 5 along the optical axis O. Because the back focus changes as the movable barrel 5 moves in the optical axis direction H, the flange focal length can be adjusted by rotating the operation member 9 as described above. After the flange focal length adjustment optical system (movable barrel 5 that holds the second lens 2b) has been adjusted to an appropriate position, the lock screw 14 is tightened to fix the adjusted position. Finally, the rubber cap 12 of the flange focal length adjustment section is fitted to complete the flange focal length adjustment operation.

[0028] As explained above, the lens device 1 can be configured to be small and space-saving, without the flange focal length adjustment section becoming larger even when the flange focal length adjustment amount of the movable barrel 5 is increased. Furthermore, by providing the cap member 16 in the relief portion 8c of the non-circular hole portion of the fixed barrel 8, dust-proofing and drip-proofing of the interior of the lens device 1 are improved. Furthermore, by providing the cap member 16 with the sliding surface 16a along which the rotation shaft portion 9a of the operation member 9 slides, it is possible to prevent the operation member 9 from tilting in the optical axis direction H, thereby improving the accuracy of flange focal length adjustment. This embodiment can provide an optical device that is advantageous in terms of adjustment of optical characteristics and compact size.

[0029] Furthermore, the relief portion 8c of the non-circular hole is formed from the center of the rotation shaft portion 9a of the operating member 9 along the optical axis direction H, so even if the operating member 9 were to tilt toward the relief portion 8c, the engagement portion 9e would simply tilt along the optical axis direction H. As a result, almost no acting force is generated to rotate the movable barrel 5. As a result, the flange back amount does not change almost at all due to the tilting of the operating member 9, allowing for stable adjustment when the flange back amount is adjusted by rotating the operating member 9.

[0030] (Variation) Fig. 7 is an enlarged cross-sectional view of a flange back adjustment portion which is a modified example of this embodiment. Fig. 8 is an enlarged view of a non-circular hole portion (hole) formed in the fixed barrel 28 of this modified example. This modified example will be explained with reference to Figs. 7 and 8. Note that the same components as those in the embodiment are given the same reference numerals and their explanation will be omitted, and only different components will be explained.

[0031] To further increase the flange back adjustment amount in the embodiment, the distance L2 from the rotation axis A1 to the outermost surface of the engaging portion 29e of the eccentric shaft portion 29b (eccentric portion) may be set to be greater than or equal to the distance L3 from the rotation axis A1 of the operating member 29 to the outer surface of the disk portion 29d (flange portion). The relationship between the distances L2 and L3 is L2 ≥ L3. That is, in the direction perpendicular to the rotation axis A1, at least a portion of the engaging portion 29e is configured to be outside the disk portion 29d of the operating member 29, which does not penetrate the fixed barrel 28. In this configuration, the relief portion 28c connected to the arc portion 28a constituting the non-circular hole formed in the fixed barrel 28 for inserting the operating member 29 is enlarged. The enlarged relief portion 28c also increases the size of the cap member 26 (first cap member), but the flange back adjustment portion does not increase in size.

[0032] The reason for this reduction in size is that the flange focal length adjustment section can be achieved without increasing the size of the rubber cap 12 and the cover member 13. First, the cap member 26 is large and protrudes in the optical axis direction H from the outer surface of the disk portion 29d of the operation member 29, but the protruding portion 26a of the cap member 26 is hidden by the rear fixed barrel 6, so there is little effect on the appearance. Because the cap member 26 is fixed to the fixed barrel 28 by adhesive, double-sided tape, or press-fitting, even if water or dust enters through the gap between the cover member 13 and the rear fixed barrel 6, the water or dust will not penetrate into the interior of the fixed barrel 28. This modification makes it possible to provide an optical device that is advantageous in terms of adjustment of optical characteristics and compact size.

[0033] (Application example) 9 is a schematic diagram showing an example of the configuration of a camera device 100 (image capture device) that uses a lens device 1 according to an embodiment of the present invention. The image capture device shown in FIG. 9 includes the lens device 1 and a camera device 100 that is configured with a camera body 100a having an image sensor 100b that captures an image formed by the lens device 1. The image capture device may also be configured such that the lens device 1 is detachably attached to the camera body 100a (image capture device body) of the camera device 100.

[0034] Although the preferred embodiments, modifications, and application examples of the present invention have been described above, the present invention is not limited to these embodiments, modifications, and application examples, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0035] 1. Lens device (optical device) 2b Second lens (optical element) 5. Moving Cylinder 5a Straight groove (guide section) 8, 28 Fixed cylinder 9, 29 Operating member 9a Rotating shaft part 9b, 29b Eccentric shaft part (eccentric part) 9e, 29e Engagement part 29d Disk part (flange part) 12 rubber cap (second cap member) 16 Cap member (first cap member) 16a Sliding surface 14 Lock screw (fixing member) 100 Camera device (imaging device) A1 rotation axis O optical axis

Claims

1. A fixed cylinder; a movable barrel disposed inside the fixed barrel and holding an optical element; a mechanism for moving the movable barrel along the optical axis by rotating the movable barrel around the optical axis; an operating member that is disposed through the fixed barrel and is rotatably operated, the operating member has a rotation shaft portion including a rotation shaft of the rotation operation, and an eccentric portion eccentric from the rotation shaft, the eccentric portion includes an engaging portion that engages with a guide portion formed on the movable barrel along the optical axis, a distance from the rotation shaft to an outermost surface of the engagement portion in a direction perpendicular to the rotation shaft is greater than a radius of the rotation shaft portion; The fixed cylinder is formed with a non-circular hole through which the operating member passes, An optical device characterized in that, by rotating the operating member, the engagement portion slides along the guide portion on the movable barrel and rotates the movable barrel around the optical axis, and the mechanism moves the movable barrel along the optical axis.

2. 2. The optical device according to claim 1, wherein a first cap member is disposed in the hole.

3. 3. The optical device according to claim 2, wherein the first cap member includes a sliding surface on which the rotation shaft portion slides.

4. 4. The optical device according to claim 1, wherein the longitudinal direction of the hole is aligned with the optical axis.

5. 5. The optical device according to claim 1, wherein the mechanism includes a cam mechanism or a helicoid mechanism.

6. 6. The optical device according to claim 1, wherein the engaging portion includes a spherical surface that contacts the guide portion.

7. An optical device as described in any one of claims 1 to 6, characterized in that in a direction perpendicular to the rotation axis, the distance from the rotation axis to the outermost surface of the engagement portion is greater than the radius of the flange portion of the operating member that does not penetrate the fixed tube.

8. 8. The optical device according to claim 1, further comprising a fixing member that fixes the operating member to the fixed barrel so that the operating member is not rotated.

9. 9. The optical device according to claim 8, further comprising a second cap member that covers the operating member and the fixing member.

10. 10. The optical device according to claim 1, which is detachably mounted on an imaging device body.

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

Images