JP2016128852A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel that is resistant to impacts.SOLUTION: A lens barrel has: a cylindrical movable unit that is movable in an optical axis direction, and has a flange shape part on a subject side; a cam ring that is arranged on a radial direction inner side of the movable unit; a stationary sensor holding member that is arranged on an imaging plane side of the movable unit and on a radial direction outer side of the cam ring, and has a sensor for detection of a rotation of the cam ring mounted; a reflection member holding frame that is arranged on a radial direction outer side of the sensor holding member, has a reflection member mounted, and integrally rotates with the cam ring; a stationary first appearance member that is arranged on an outer side of the reflection member; and a second appearance member that is present on a subject side of the first appearance member, and is fixedly coupled to the first appearance member. When an impact is applied to an end face on the subject side of the cylindrical movable unit, a face on an imaging plane side of the flange shape part hits the second appearance member, and impact force is transmitted to the first appearance member via the second appearance member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens barrel that includes an optical element such as a lens and a photoelectric conversion element such as an imaging element, and is drawn out from a casing when in use. The lens barrel is mounted on an imaging device such as an interchangeable lens, a video camera, or a digital still camera.

  Conventionally, a digital still camera or a digital video camera as an image pickup apparatus of this type is configured by attaching a lens barrel, which is a lens barrel apparatus that holds a plurality of lenses so as to be movable in the direction of the optical axis, to a casing. The lens barrel is extended from the wide-angle state (wide state) to the telephoto state (tele state) toward the subject side with respect to the housing.

  In the lens barrel described in Patent Document 1, as shown in FIG. 8, the projecting portion 114 is formed with an abutting portion that abuts on the master flange 190 in the retracted state of the first group frame 110. In some cases, the protrusion 114 is configured to prevent damage to the cam groove in advance of the master flange 190.

JP 2014-142666 A

  In the prior art disclosed in Patent Document 1 described above, for example, there is a problem in performance when there is a part that changes the performance of the lens barrel when subjected to an impact behind the master flange 190. The same configuration cannot be taken.

  An object of the present invention is to provide a lens barrel that ensures impact resistance performance while achieving downsizing of the barrel unit in a lens barrel mainly having a retractable configuration.

  In order to achieve the above object, the lens barrel of the present invention holds at least one lens and is located closest to the subject and can be advanced and retracted in the optical axis direction. A cylindrical movable part having a cam ring disposed on the radially inner side of the movable part, an imaging surface side of the movable part, and A fixed sensor holding member that is mounted on the outer side in the radial direction of the cam ring and that is equipped with a sensor for detecting the rotation of the cam ring, and is positioned on the outer side in the radial direction of the sensor holding member, and the position is detected by the sensor. A reflective member holding frame that is mounted with a reflective member to rotate integrally with the cam ring, a fixed first appearance member disposed outside the reflective member holding frame, and the first appearance On the subject side of the member and against the first exterior member There is a second appearance member connected and fixed, and when an impact is applied to the subject-side end surface of the cylindrical movable portion, the surface on the imaging surface side of the flange-shaped portion hits the second appearance member. The impact force is transmitted to the first appearance member via the second appearance member.

  ADVANTAGE OF THE INVENTION According to this invention, provision of the lens-barrel which ensured impact-resistant performance is achieved, achieving size reduction of a lens-barrel unit.

The perspective view of the camera which is an Example of this invention Cross section of lens barrel (WIDE) Cross section of lens barrel (TELE) An exploded perspective view showing that the cam follower of the L3A group lens barrel 3A is engaged with the rectilinear groove of the fixed cylinder 7. 3A is an exploded perspective view showing that the rotation of the second group is restricted by the guide bar with respect to 3A An exploded perspective view showing that the first group cylinder 1b is restricted by the guide bar with respect to the L3A group lens barrel 3A. Cross-sectional view of the lens barrel showing the location that will be reached first when an impact occurs The exploded perspective view which looked at the zoom drive unit in a present Example from the object side The exploded perspective view which looked at the zoom drive unit in a present Example from the sensor side Development view of first group cam grooves 8c1-8c3 Development view of third group cam groove 8a1-8a3 and second group cam groove 8b Conventional example

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a camera according to an embodiment of the present invention. In FIG. 1, L is a lens barrel, B is a camera body, D is a power button, and Z is a zoom operation key. When the camera is used, after the power button D is pressed and the power is turned on, the zoom operation key Z is operated, whereby the lens barrel expands and contracts and the photographing magnification changes.

  Next, the lens barrel that is a feature of the present invention will be described in detail with reference to FIGS. FIG. 2 is a cross-sectional view of the lens barrel at the widest angle (WIDE). FIG. 3 is a cross-sectional view of the lens barrel at the maximum telephoto (TELE). FIG. 4 is an exploded perspective view showing that the cam follower of the L3A group lens barrel 3A is engaged with the rectilinear groove of the fixed cylinder 7. FIG. FIG. 5 is an exploded perspective view showing that the rotation of the second group is restricted by the guide bar with respect to 3A.

  FIG. 6 is an exploded perspective view showing that the first group cylinder 1b is restricted by the guide bar relative to the L3A group lens barrel 3A. FIG. 7 is a cross-sectional view of the lens barrel, showing the first part when an impact occurs. FIG. 8 is an exploded perspective view of the manual zoom drive unit as viewed from the object side. FIG. 9 is an exploded perspective view of the manual zoom drive unit as viewed from the sensor side. FIG. 10 is a development view of the first group cam grooves 8c1 to 8c3. FIG. 11 is a development view of the third group cam grooves 8a1 to 8a3 and the second group cam grooves 8b.

  In the lens barrel L, the first lens unit L1, the second lens unit L2, the third lens unit L3A, and L3B, the fourth lens unit L4, the first lens unit, in order from the subject side to the image plane side. A five-lens group L5 is provided.

  The first lens group to the third lens group are zooming lenses that can be zoomed from the wide-angle side to the telephoto side by moving the respective groups back and forth in the optical axis direction along a predetermined cam locus. is there. The fourth lens unit L4 is a focusing lens that performs a focusing operation by moving in the optical axis direction. The fifth lens group L5 is a fixed lens group. The first lens group L1 is held by the first group barrel 1a, the second lens group L2 is held by the second group barrel 2, and the subject side group L3A of the third lens group is held by the L3A group barrel 3A. The lens L3B on the image plane side of the third lens group is held by a shift barrel 3B that can move in a plane perpendicular to the optical axis, and the fourth lens group L4 is held by the fourth group barrel 4, and is a fixed lens. The group L5 is held by the fifth group barrel 5.

  In the third lens group, an aperture shutter ND unit 6 for adjusting the amount of light is disposed between the lens group L3A on the subject side and the lens group L3B on the imaging surface side. It is fixed to the fifth group barrel 5. The fixed cylinder 7 is fixed to the fifth group barrel 5 with screws. The cam ring 8 is diameter-fitted with the outer diameter of the fixed cylinder 7 and rotates at a fixed position around the optical axis. By rotating the cam ring 8, the first lens group to the third lens group described above are driven in the optical axis direction along the cam locus formed on the cam ring 8, and zooming is possible from the wide angle side to the telephoto side. It has become.

  Three group cam followers 3A1 to 3A3 are provided at three locations at substantially equal intervals in the circumferential direction on the outer peripheral portion of the L3A group lens barrel 3A. The third group cam followers 3A1 to 3A3 pass through elongated holes 7a1 to 7a3 (7a3 is not shown) formed in the fixed cylinder 7 and extending in the optical axis direction to the third group cam grooves 8a1 to 8a3 formed in the cam ring 8. Engage. Thereby, the L3A group lens barrel 3A is positioned in the optical axis direction in a state where the rotation is restricted.

  On the inner peripheral side of the 3A group lens holding frame 3A, two two group guide bars 2b and 2c extending in the optical axis direction are provided. The end portions of the second group guide bars 2b and 2c on the optical axis direction imaging surface side are held by the L3A group lens barrel 3A. The ends of the second group guide bars 2b and 2c on the subject side in the optical axis direction are respectively fixed and held by the L3A group barrel cover member 3A4. The L3A group barrel cover member 3A4 is fixed to the L3A group barrel 3A with screws.

  With respect to the second group guide bars 2b and 2c, a sleeve hole 2d formed in the second group lens holding frame 2 is fitted into one second group guide bar 2b so as to be relatively movable in the optical axis direction. An arc groove 2e formed in the second group lens holding frame 2 is engaged with the guide bar 2c so as to be relatively movable in the optical axis direction. A second group cam follower 2a is fixed to the outer periphery of the second group barrel 2 with screws. The second group cam follower 2 a is engaged with a second group cam groove 8 b formed in the cam ring 8. Therefore, the second group lens holding frame 2 is positioned in the optical axis direction with the second group lens holding frame 2 being restricted in rotation with respect to the L3A group lens barrel 3A.

  In the 3A group lens holding frame 3A, a sleeve hole 3A5 and a U groove 3A6 are formed. The sleeve hole 3A5 of the 3A group lens holding frame 3A is engaged with the first group guide bar 1d, and the U groove 3A6 is engaged with the first group guide bar 1e.

  The two first group guide bars 1d and 1e are held by the first group cylinder 1b at the ends on the subject side in the optical axis direction. Further, the end portions of the first group guide bars 1d and 1e on the imaging surface side in the optical axis direction are respectively fixed and held by a first group cylinder cover member 1c for holding both guide bars 1d and 1e. . The first group cylinder cover member 1c is fixed to the first group cylinder 1b with screws 1g at three locations. With this configuration, the first group cylinder 1b is in a state in which the rotation is restricted with respect to the L3A group lens barrel 3A.

  The first group barrel 1a is fixed to the first group cylinder 1b with screws. Three first group cam followers 1f1 to 1f3 (1f2 is not shown) are provided at substantially equal intervals in the circumferential direction on the inner peripheral portion of the first group cylinder 1b. By engaging the first group cam followers 1f1 to 1f3 with the first group cam grooves 8c1 to 8c3 formed in the cam ring 8, the first group cylinder 1b is positioned in the optical axis direction.

  When the cam ring 8 is rotated by adopting the above-described configuration, the first lens group L1, the second lens group L2, the third lens group L3A, and L3B are cam grooves 8a1 to 8a3, 8b, It moves in the optical axis direction along the trajectory 8c1 to 8c3.

  Next, the assembly procedure of the first lens group to the third lens group will be described with reference to FIG. First, in a state where the cam ring 8 is fitted and assembled to the fixed cylinder 7, the first group cylinder cover member 1c is inserted from the subject side in the optical axis direction. Thereafter, the second group third group unit 23a in a state where the third group cam follower 3A1 to 3A3 and the second group cam follower 2a are not attached is dropped in the optical axis direction. Thereafter, the third group cam followers 3A1 to 3A3 are passed through the cam grooves 8a1 to 8a3 of the cam ring 8 and the long holes 7a1 to 7a3 of the fixed cylinder 7 from the outside of the cam ring 8, and are screwed into the 3A group lens holding frame 3A. Stop.

  Thereafter, the second group cam follower 2 a is penetrated from the outside of the cam ring 8 into the cam groove 8 b of the cam ring 8 and fixed to the second group barrel 2 with screws. Thereafter, the first group cylinder 1b is dropped from the subject side to the imaging surface side, and the first group cylinder cover member 1c is positioned with respect to the first group cylinder cover member 1c with the first group cylinder cover member 1c positioned. The cylinder 1b is fixed with screws.

  Next, details of the present embodiment will be described. Reference numeral 16 denotes a manual focus (MF) operation ring, which is fixed integrally with the MF appearance ring 17 and is rotatably supported between the MF fixing member 15 and the MF cover member 18. When the photographer manually rotates the MF operation ring 16, a sensor (not shown) detects and performs manual focus adjustment according to the rotation amount.

  Reference numeral 12 denotes a manual zoom (MZ) operation ring which is fixed integrally with the MZ appearance ring 13 and is rotatably supported between the MZ fixing member 14 and the MZ cover member 11. The MF cover member 18 and the MZ fixing member 14 described above are also fixed integrally by screws.

  Reference numeral 10 denotes a reflection member holding frame, which is supported in the optical axis direction by being sandwiched between the MZ cover member 11 and the sensor holding frame 9 and is rotatably supported at a fixed position with respect to the sensor holding frame 9.

  Reference numeral 10b denotes an MZ operation ring connection key provided on the reflection member holding frame 10. The MZ operation ring connection key 10 b is fixed using two screws, and engages with the engagement portion 12 a of the MZ operation ring 12. Reference numeral 10 c denotes a cam ring connection key provided on the reflection member holding frame 10. The cam ring connection key 10 c is fixed using two screws, and engages with the engaging portion 8 d of the cam ring 8.

  When the photographer manually rotates the MZ operation ring 12, the reflecting member holding frame 10 can be rotated around the optical axis via the MZ operation ring connection key 10b. The reflecting member holding frame 10 can further rotate the cam ring 8 around the optical axis via the cam ring connecting key 10c. As described above, since the cam ring 8 drives and holds the first to third lens groups that hold the variable power lens group in the optical axis direction, the imaging magnification can be changed.

  Reference numeral 9 a denotes an optical position detection sensor that is bonded and fixed to the sensor holding frame 9. Reference numeral 10 a denotes a sheet-like reflecting member, which is fixed to the inner peripheral surface of the reflecting member holding frame 10.

  The surface of the reflecting member 10a is patterned in light and dark so that bright portions with high reflectivity and dark portions with low reflectivity are alternately arranged in the rotation direction. The patterned surface is fixed to the inner peripheral surface of the reflecting member holding frame 10 so as to face the optical position detection sensor side (optical axis center side).

  The optical position detection sensor 9a is a sensor having a light emitting part and a light receiving part. Therefore, when the reflecting member holding frame 10 rotates, the optical position detection sensor 9a can detect a light / dark pattern and detect the rotation angle of the reflecting member holding frame 10.

  In FIG. 10, in the TELE state, the group of cam followers is located at 8a6. In the WIDE state, the first group of cam followers is located at 8a5. The intersection angle of the cams of the first group cam grooves 8c1 to 8c3 in TELE is an angle indicated by 8a7. In the present embodiment, the intersection angle of the cam in TELE is about 40 degrees. Also, as TELE → MIDELE, the cam crossing angle becomes steep and becomes about 60 degrees (8a8). However, as it approaches WIDE, the cam crossing angle becomes gentle and is almost flat in the final WIDE state ( (About 0 degree).

  In the TELE state, when an impact is applied to the distal end portion 1b1 of the first group cylinder 1b, the angle of intersection of the first group cam in the TELE is about 40 degrees, so a part of the impact force becomes a force that rotates the cam ring. There is little damage to the group cam followers 1f1 to 1f3. Even if an impact is applied to the distal end portion 1b1 of the first group cylinder 1b in the state of MIDDLE, the angle of intersection of the first group cam is about 60 degrees. Therefore, as in the case of TELE, part of the impact force is a force that rotates the cam ring. Thus, the damage to the first group cam followers 1f1 to 1f3 is small. On the other hand, when an impact is applied to the tip 1b1 of the first group cylinder 1b in the WIDE state, since the intersection angle of the first group cam is flat, it cannot be changed to a force for rotating the cam ring. The impact force is transmitted to the first group cam followers 1f1 to 1f3, and problems such as destruction of the cam followers 1f1 to 1f3 occur.

  For this reason, in this embodiment, the cam followers 1f1 to 1f3 are configured to be provided in advance before a problem such as destruction occurs, thereby preventing the problem from occurring.

  Specifically, the clearance 1b1 between the flange portion 1b3 and the MF fixing member 15 on the imaging surface side of the flange portion 1b3 of the first group cylinder 1b is minimized, and the cam followers 1f1 to 1f3 are undergoing elastic deformation ( Before the plastic deformation, the clearance 1b2 is contracted, the flange portion 1b4 and the MF fixing member 15 come first, and the cam followers 1f1 to 1f3 are prevented from being destroyed.

  The material of the cam followers 1f1 to 1f3 is preferably a material that is easily elastically deformed, and for example, POM is suitable.

  There is also a method in which the clearance 1b3 at the rearmost end of the first group cylinder 1b is minimized as much as possible so that the first group cylinder 1b and the sensor holding frame 9 are brought into contact with each other while the cam followers 1f1 to 1f3 are elastically deformed. However, in the present embodiment, the sensor holding frame 9 fixes the optical position detection sensor 9a by adhesion. For example, when the first group cylinder 1b hits the sensor holding frame 9 due to an impact, the optical position detection sensor 9a is fixed. If the position of the detection sensor 9a is deviated, the sensor output will change, causing a problem that the accuracy of the zoom rotation angle is reduced.

  Therefore, in this embodiment, it is desirable that the relationship between the clearance 1b2 and the clearance 1b3 is 1b2 <1b3. By doing so, the impact force is transmitted from the MF fixing member 15 → the MF cover member 18 → the MZ cover member 11, so that the impact force is exerted on the sensor holding frame 9 and the reflection member holding frame 10 which affect the sensor output. There is no transmission.

  Conversely, it is conceivable to arrange another fixing member without arranging the sensor holding frame 9 at the rearmost end of the first group cylinder 1b. However, the radius La of the lens barrel in the present invention cams the main optical system. The radius La is determined by the radius Lb of the main lens barrel portion driven by the ring and the sum of the thicknesses Lc of the sensor output component and the appearance part. Therefore, when another fixing member is arranged, the radius La becomes large. The lens barrel becomes large.

  That is, the present invention can adopt a configuration in which the lens barrel is reduced in size and has impact resistance.

  Further, 1b5 of the first group cylinder 1b is a bayonet coupling portion for attaching a hood for cutting a ghost caused by unnecessary light. In the present invention, the first flange portion 1b4 is the bayonet coupling portion 1b5. Even if an impact is applied to the front end of the hood (most end surface on the subject side) with the hood attached, the impact is applied to the flange portion 1b4 of the first-group cylinder 1b → the MF fixing member. Since 15 → MF cover member 18 → MZ cover member 11 is transmitted, the impact force is not transmitted to the sensor holding frame 9 and the reflection member holding frame 10 which affect the sensor output.

  The lens barrel of the present invention can be mounted not only on a video camera but also on various optical devices such as an imaging device such as a digital still camera and an interchangeable lens.

1b 1 group cylinder (movable part in claims), 8 cam ring, 9 sensor holding frame,
10 reflecting member holding frame, 11 MZ cover member (first appearance member in claims),
15 MF fixing member (second appearance member in claims)

Claims (4)

  A cylindrical movable part that has at least one lens and is positioned closest to the subject and can be advanced and retracted in the optical axis direction, and has a flange-shaped part on the subject side, and the movable part in the optical axis direction The cam ring disposed on the radially inner side of the movable part and the rotation of the cam ring disposed on the imaging surface side of the movable part and on the radially outer side of the cam ring are detected. A fixed sensor holding member on which a sensor for mounting is mounted, a reflecting member which is disposed radially outside the sensor holding member and detects a position by the sensor, and is integrated with the cam ring A reflecting member holding frame that rotates to the outside, a fixed first appearance member disposed outside the reflecting member, and on the subject side of the first appearance member, and connected and fixed to the first appearance member The second movable member has the cylindrical movable part. When an impact is applied to the end surface on the subject side, the surface on the imaging surface side of the flange-shaped portion hits the second appearance member, and the impact force is applied to the first appearance member via the second appearance member. A lens barrel characterized by being transmitted.   The cam ring has a cam groove for driving the movable portion in the optical axis direction, and the angular groove has a steep intersection angle on the telephoto side and is flat on the intersection angle side. The lens barrel according to Item 1.   The movable portion has a cam follower for fitting with the cam groove, and the material of the cam follower is a material that is easily elastically deformed, and when an impact occurs, before the cam follower is plastically deformed ( 3. The lens barrel according to claim 1, wherein the flange-shaped portion precedes the second appearance member within an elastic deformation range. 4.   The lens barrel according to any one of claims 1 to 3, wherein the flange-shaped portion is positioned on an imaging surface side of a mounting portion to which a hood is coupled with a bayonet.