JP5558236B2 - Lens barrel - Google Patents

Description

  The present invention relates to a retractable lens barrel that can be shortened when not in use.

  In a lens barrel that holds a lens used in an imaging device such as a still camera and a video camera, the length in the direction along the optical axis of the optical system member of the lens barrel when not in use What was comprised so that expansion-contraction was possible so that it could be made shorter than length was known. Such a lens barrel that can be shortened when not in use is generally referred to as a retractable lens barrel, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-169285.

  The lens barrel disclosed in Japanese Patent Application Laid-Open No. 2009-169285 further shortens the overall length of the lens barrel when retracted by retracting some of the plurality of lenses from the optical axis in the direction perpendicular to the axis. It has the composition to do. In such a lens barrel, not only a plurality of lenses are gathered in the direction along the optical axis when retracted, but the lenses are overlapped in the direction perpendicular to the axis by retracting a relatively small diameter lens from the optical axis. By disposing the plurality of lenses, the plurality of lenses are densely packed so as to increase the ratio of the lens volume to the lens barrel volume, thereby reducing the volume when retracted.

  As described above, in a lens barrel in which a part of a plurality of lenses is retracted from the optical axis to retract the lens when the lens is retracted, each member is opened to avoid interference between the holding members that hold the lens when retracted. It is necessary to provide a part and a notch. These openings and cuts allow a light beam unnecessary for photographing to pass through during use such as photographing, and this unnecessary light beam may affect the photographing result.

  For this reason, in the lens barrel disclosed in Japanese Patent Application Laid-Open No. 2009-169285, a flexible light-shielding sheet is disposed in the opening of the holding member, thereby blocking unnecessary light rays. Yes. When the sheet is retracted, the sheet is deformed so as to be accommodated between the members by being pushed by a holding member or the like, so that the size reduction of the lens barrel is not hindered.

JP 2009-169285 A

  When a light-shielding sheet is provided in a place where unnecessary light passes, like the lens barrel disclosed in Japanese Patent Application Laid-Open No. 2009-169285, a part of the sheet holds the lens during use such as photographing. There is a case where the holding member is touched. As described above, when the sheet comes into contact with the holding member during use, the posture of the holding member is changed by the reaction force of the deformed sheet, which may cause variation in lens positioning.

  The present invention has been made in view of the above problems, and can be retracted so that unnecessary light can be prevented from passing through an opening provided in the lens holding member and the lens can be positioned with high accuracy. An object is to provide a lens barrel.

The lens barrel of the present invention holds a plurality of lenses, and a retracted state in which all the lenses are arranged on the optical axis and a retractable lens made up of a part of the lenses are retracted from the optical axis. a lens barrel that is capable of changing configuration, a collapsed state having a reduced length of the optical axis direction than the feeding state is a holding member having an opening portion in which the optical axis passes, the retracted A lens is held and can be rotated around a rotation axis parallel to the optical axis fixed to the holding member, and when viewed from the direction along the optical axis, the opening is in the extended state. A retractable lens frame that is positioned in a region overlapping with the support member and is movably supported relative to the holding member so as to be retracted from the opening in the retracted state, and the holding member and the retractable lens frame disposed between, A pivotable about Kikaido axis, when viewed from the direction along the optical axis, in the feeding state shields the region located in the direction in which the retracting lens frame of said opening is retracted And a light shielding blade supported so as to be relatively movable with respect to the holding member so as to retract from the opening and move to a position overlapping the retracting lens frame in the retracted state , The retractable lens frame and the light shielding blade have an engaging portion that engages with each other, and the light shielding blade moves around the rotation axis in conjunction with the movement of the retractable lens frame via the engaging portion. In the rotating lens barrel, the rotation shaft is a columnar member provided between a pair of flat portions provided on the holding member and parallel to each other and perpendicular to the optical axis, and the retraction shaft The lens frame slides around the rotation shaft A cylindrical portion having an outer peripheral shape smaller than the cylindrical portion provided at one end in a direction along the optical axis of the cylindrical portion, and the outer peripheral shape being centered on the rotation axis A movement of the cylindrical portion in the direction along the rotation axis is restricted by the cylindrical portion being disposed between the pair of plane portions, A sliding hole that is slidably fitted on the outer periphery of the cylindrical surface portion is provided, and the thickness of the portion along the optical axis of the portion where the sliding hole is formed is along the optical axis of the cylindrical surface portion. It is characterized by being thinner than the thickness in the direction .

  According to the present invention, it is possible to realize a retractable lens barrel capable of preventing the passage of unnecessary light from an opening provided in the lens holding member and accurately positioning the lens.

It is sectional drawing of the lens-barrel in an extended state. It is sectional drawing of the lens-barrel in a retracted state. It is the figure which looked at the rectilinear frame in the extended state, the 3rd group lens holding frame, and the light-shielding blade from back. It is the figure which looked at the rectilinear frame in the retracted state, the 3rd group lens holding frame, and the light-shielding blade from back. It is the figure which looked at the 3rd group lens holding frame from back. It is A arrow directional view of FIG. It is the figure which looked at the light-shielding blade from back. It is a B arrow view of FIG. It is a figure explaining operation | movement of a 3rd group lens holding frame and a light-shielding blade. It is a figure explaining operation | movement of a 3rd group lens holding frame and a light-shielding blade. It is sectional drawing of a rotating shaft.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each drawing used for the following description, the scale is different for each component in order to make each component large enough to be recognized on the drawing. It is not limited only to the quantity of the component described in the figure, the shape of the component, the ratio of the size of the component, and the relative positional relationship of each component.

  The lens barrel 1 of the present embodiment is applied to an imaging apparatus such as a still camera and a video camera, and includes a plurality of frame members that hold optical system members including lenses and the like. . The lens barrel 1 is along the optical axis so that the length of the optical system member of the lens barrel 1 in the direction along the optical axis when not photographing can be made shorter than the length when photographing. It is configured to be stretchable in the direction. Such a lens barrel 1 is generally referred to as a retractable lens barrel.

  In the following description, the optical axis of the photographing optical system member in the lens barrel 1 is represented by the symbol O. In this direction along the optical axis O, the object side (object side) is defined as the front, and the direction in which each frame member constituting the lens barrel is directed forward is referred to as the feeding direction. On the other hand, in the direction along the optical axis O, the imaging side (image side) is the rear, and the direction in which each frame member heads backward is referred to as the retraction direction. The rotation direction of each component in the lens barrel is represented by the rotation direction viewed from the front side.

  FIG. 1 shows a cross-sectional view of the lens barrel 1 in the extended state (during shooting). FIG. 2 is a cross-sectional view of the lens barrel 1 in the retracted state (during non-shooting). The lens barrel 1 is configured to hold an optical system member including a first group lens 21, a second group lens 22, a third group lens 23, and a fourth group lens 24. The optical system member disposed in the lens barrel 1 is not limited to the lens, and may include an optical filter such as an ND filter, a prism, and the like.

  The lens barrel 1 is a frame member that holds and can move the first group lens 21, the second group lens 22, the third group lens 23, and the fourth group lens 24, respectively. A second group lens holding frame 12, a third group lens holding frame 13, and a fourth group lens holding frame 14 are provided. The first group lens holding frame 11, the second group lens holding frame 12, the third group lens holding frame 13, and the fourth group lens holding frame 14 are movable relative to the fixed frame 2 in the optical axis O direction. is there. Further, the lens barrel 1 is restricted from rotating around the optical axis O and the rotating frame 4 and the cam frame 5 that move forward and backward in the direction of the optical axis O while rotating around the optical axis O by the driving force of an electric motor (not shown). And a moving frame 3 that moves forward and backward in the optical axis O direction.

  The fixed frame 2 is a member that is fixed to the imaging device in order to fix the lens barrel 1 to the imaging device. The fixed frame 2 is a substantially cylindrical member, and a cam groove 2a is carved on an inner peripheral surface which is a cylindrical surface with the optical axis O as a central axis. The cam groove 2a is provided with a predetermined cam profile that is inclined with respect to the optical axis O. An electric motor (not shown) is fixed to the outer peripheral portion of the fixed frame 2. In the present embodiment, as an example, an imaging element 26 in a form called a CCD or a CMOS sensor is fixed to the rear of the fixed frame 2 via a holding plate 27. The imaging element 26 is fixed so that the light receiving surface is orthogonal to the optical axis O. The image sensor 26 may be fixed to the fixed frame 2 via a so-called image blur correction mechanism that holds the image sensor 26 movably with respect to the optical axis O.

  The rotating frame 4 is a substantially cylindrical frame member that fits inside the fixed frame 2. The rotating frame 4 is disposed on the inner peripheral portion of the fixed frame 2 so as to be rotatable around the optical axis O and to be movable back and forth along the optical axis O. A cam follower that is slidably engaged with the cam groove 2 a of the fixed frame 2 is provided on the outer peripheral portion of the rotating frame 4. The moving frame 3 is a substantially cylindrical frame member that fits inside the rotating frame 4. The moving frame 3 is disposed on the inner periphery of the rotating frame 4 in a state in which the rotation around the optical axis O is described. A cam groove 3 a is carved on the inner peripheral surface of the moving frame 3. The cam groove 3a is provided with a predetermined cam profile.

  The rotating frame 4 is rotationally driven around the optical axis O relative to the fixed frame 2 by the driving force of the electric motor. The rotating frame 4 moves forward and backward along the optical axis O along with the rotation around the optical axis O due to the engagement between the cam follower and the cam groove 2 a of the fixed frame 2.

  The cam frame 5 is a substantially cylindrical frame member that fits inside the moving frame 3. The cam frame 5 is disposed on the inner peripheral portion of the moving frame 3 so as to be rotatable around the optical axis O and to be movable back and forth along the optical axis O. A cam follower that is slidably engaged with the cam groove 3 a of the moving frame 3 is provided on the outer peripheral portion of the cam frame 5.

  Cam grooves 5 a and 5 b and a lens retracting cam groove (not shown) are carved on the inner peripheral surface of the cam frame 5. A cam groove 5 c is carved on the outer peripheral surface of the cam frame 5. The cam grooves 5a, 5b and 5c and the lens retracting cam groove are each provided with a predetermined cam profile.

  The cam frame 5 is driven to rotate around the optical axis O relative to the moving frame 3 together with the rotating frame 3 by the driving force of the electric motor. The cam frame 5 moves forward and backward along the optical axis O along with the rotation around the optical axis O by the engagement of the cam follower and the cam groove 3 a of the moving frame 3.

  The first group lens holding frame 11 is a substantially cylindrical frame member that holds the first group lens 21 on the optical axis O. The first group lens holding frame 11 is fitted inside the moving frame 3 and fitted with a predetermined gap outside the cam frame 5. The first group lens holding frame 11 is arranged such that the rotation around the optical axis O is restricted, and the first group lens holding frame 11 can move forward and backward along the optical axis O relative to the cam frame 5.

  A cam follower that is slidably engaged with the cam groove 5 c of the cam frame 5 is provided on the inner peripheral surface of the first group lens holding frame 11. Since the rotation of the first lens group holding frame 11 around the optical axis O is restricted, the first lens group holding frame 11 is moved to the optical axis O along with the rotation of the cam frame 5 by the engagement of the cam follower and the cam groove 5c of the cam frame 5. Move forward and backward along.

  The second group lens holding frame 12 is a frame member having a shape that holds the second group lens 22 on the optical axis O behind the first group lens 21 and fits in the cam frame 5 from the front of the cam frame 5. is there. The second group lens holding frame 12 is disposed so that the rotation around the optical axis O is restricted, and the second group lens holding frame 12 can move forward and backward along the optical axis O relative to the cam frame 5.

  A cam follower that is slidably engaged with the cam groove 5 a of the cam frame 5 is provided on the outer periphery of the second group lens holding frame 12. Since the rotation of the second lens group holding frame 12 around the optical axis O is restricted, the engagement of the cam follower and the cam groove 5a of the cam frame 5 causes the optical axis O to move along with the rotation of the cam frame 5. Move forward and backward along.

  The third group lens holding frame 13 that is a retracting lens frame is a frame member that holds the third group lens 23 on the optical axis O behind the second group lens 23 when the lens barrel 1 is in the extended state. It is. As will be described in detail later, as shown in FIG. 2, the third group lens holding frame 13 is disposed so as to retract from the optical axis O when the lens barrel 1 is in the retracted state. As described above, the lens barrel 1 of the present embodiment retracts the third group lens holding frame 13 from the optical axis O in the retracted state, so that the second lens group holding frame 12 and the fourth group lens 4 are retracted in the retracted state. The distance in the optical axis O direction from the group lens holding frame 14 can be shortened, and the length of the lens barrel 1 in the retracted state can be shortened. Although described in detail later, the third group lens holding frame 13 is held by the rectilinear frame 7.

  The rectilinear frame 7 as a holding member is a substantially cylindrical frame member having a shape that fits in the cam frame 5 from behind the cam frame 5. The rectilinear frame 7 is disposed so that the rotation around the optical axis O is restricted, and the rectilinear frame 7 can move forward and backward along the optical axis O relative to the cam frame 5.

  A cam follower that is slidably engaged with the cam groove 5 b of the cam frame 5 is provided on the outer peripheral surface of the rectilinear frame 7. Since the rotation of the first lens group holding frame 11 around the optical axis O is restricted, the first lens group holding frame 11 is moved to the optical axis O along with the rotation of the cam frame 5 by the engagement of the cam follower and the cam groove 5b of the cam frame 5. Move forward and backward along. Since the rectilinear frame 7 is restricted from rotating around the optical axis O, the rectilinear frame 7 moves forward and backward along the optical axis O along with the rotation of the cam frame 5 by the engagement of the cam follower and the cam groove 5 c of the cam frame 5. To do. The third group lens holding frame 13 moves forward and backward along the optical axis O as the rectilinear frame 7 moves forward and backward.

  In addition to the third group lens holding frame 13, the rectilinear frame 7 holds a shutter unit 25 and a light shielding blade 8, which will be described later, behind the third group lens holding frame 13. The shutter unit 25 is configured to have a shutter function for opening and closing the photographing optical path and an aperture function for adjusting the photographing light amount.

  In the rectilinear frame 7, a cylindrical slide shaft 7a substantially parallel to the optical axis O is provided. On the other hand, the shutter unit 25 is provided with a through hole 25b slidably fitted to the slide shaft 7a. The shutter unit 25 is disposed so as to be movable along the optical axis O relative to the rectilinear frame 7.

  Further, the shutter unit 25 is provided with a through hole 25a in a region overlapping with the third group lens holding frame 13 when viewed from the optical axis O direction in the retracted state of the lens barrel 1. When the lens barrel 1 moves from the extended state to the retracted state, the shutter unit 25 moves relatively forward with respect to the third group lens holding frame 13. At this time, the rear end portion of the third group lens holding frame 13 is inserted into the through hole 25a. As described above, when the lens barrel 1 is retracted, a part of the third group lens holding frame 13 and a part of the shutter unit 25 are overlapped when viewed from a direction orthogonal to the optical axis O. Thus, the length of the lens barrel 1 in the retracted state can be shortened.

  The fourth group lens holding frame 14 is a frame member that holds the fourth group lens 24 on the optical axis O behind the shutter unit 25. The fourth group lens holding frame 14 is disposed so as to be able to advance and retreat along the optical axis O in a state where rotation around the optical axis O is restricted. The fourth group lens frame 14 is configured to move in a direction along the optical axis O by an actuator different from the electric motor that rotationally drives the rotary frame 4. The fourth group lens 24 is a so-called focusing lens, and when the focusing distance of the optical system member is changed, the fourth group lens holding frame 14 is driven back and forth along the optical axis O.

  Below, the detailed structure of the rectilinear advance frame 7, the 3rd group lens holding frame 13, and the light-shielding blade 8 is demonstrated. FIG. 3 is a view of the rectilinear frame 7, the third group lens holding frame 13, and the light shielding blade 8 when viewed from the rear when the lens barrel 1 is in the extended state. FIG. 4 is a view of the rectilinear frame 7, the third group lens holding frame 13, and the light shielding blade 8 when viewed from the rear when the lens barrel 1 is in the retracted state.

  As shown in FIG. 3, the rectilinear frame 7 that is a holding member has a planar portion 7 b having a planar shape substantially orthogonal to the optical axis O on the front side, and is substantially the center of the optical axis behind the planar portion 7 b. A member having a cylindrical side surface portion 7d. An opening 7c that is a through hole is formed in the flat surface portion 7b. The opening 7c has a shape that allows the rear end portion of the second group lens holding frame 13 to be inserted therein.

  In the present embodiment, the opening 7c is a substantially circular through hole. In the present embodiment, since the outer diameter of the rearmost lens of the second group lens 22 is larger than the outer diameter of the lens having the largest outer diameter of the third group lens 23, when viewed from the optical axis O direction, The opening 7 c has a larger diameter than the third group lens 23.

  Moreover, the rotating shaft 10 is erected on the flat surface portion 7b. The rotation shaft 10 is a shaft member that is separated from the optical axis O by a predetermined distance R1 and is substantially parallel to the optical axis O, and can rotate at least one of the third group lens holding frame 13 and the light shielding blade 8. It is a member to support.

  Specifically, in the present embodiment, the rotation shaft 10 is a cylindrical member, and as shown in FIG. 11, is substantially parallel to the flat surface portion 7 b and the flat surface portion 7 b and radially inward from the side surface portion 7 d. The front end portion and the rear end portion are supported by the tongue piece portion 7h extending to the front.

  Further, the flat portion 7b of the rectilinear frame 7 is in contact with a third group lens holding frame 13 and a light shielding blade 8 which will be described later, so that the third group lens holding frame 13 and the light shielding blade 8 around the rotation axis 10 are arranged. Stoppers 7f and 7g, which are convex portions for positioning, are provided.

  A receding opening 7 e that is a through hole is formed in the side surface portion 7 d of the rectilinear frame 7. As shown in FIG. 2, the retracting opening 7e is provided so that a part of the third group lens holding frame 13 can be accommodated therein when the third group lens holding frame 13 is retracted from the optical axis O. ing. In other words, the retracting opening 7e is a through-hole provided at a position where the side group 7d interferes with the third group lens holding frame 13. Thus, by providing the retracting opening 7e in the side surface portion 7d, the third group lens holding frame 13 can be retracted further away from the optical axis O in the retracted state. The distance in the optical axis O direction with respect to the fourth group lens holding frame 14 can be further shortened.

  FIG. 5 is a view of the third lens group holding frame 13 as viewed from the rear. As shown in FIG. 5, the third group lens holding frame 13 includes a cylindrical portion 13d, an arm portion 13b extending from the outer peripheral portion of the cylindrical portion 13d, and a third portion fixed to the distal end portion of the arm portion 13b. A lens holding portion 13a for holding the group lens 23 and a contact portion 13f extending from the lens holding portion 13a are provided.

  The cylindrical portion 13d is a substantially cylindrical portion in which a sliding hole 13c that is slidably fitted to the outer periphery of the sliding shaft 10 is formed. In the third group lens holding frame 13, the central axis of the sliding hole 13c and the lens optical axis of the third group lens 23 held in the lens holding portion 13a are substantially parallel, and the central axis and the lens optical axis. Is approximately the same as the distance R1 between the central axis of the rotation shaft 10 and the optical axis O. Therefore, by fitting the rotation shaft 10 and the sliding hole 13c, the third lens group holding frame 13 can rotate about the rotation shaft 10 substantially parallel to the optical axis O with respect to the rectilinear frame 7. Supported.

  As shown in FIG. 11, the length of the cylindrical portion 13d in the axial direction is slidably inserted between the flat surface portion 7b and the tongue piece portion 7h of the rectilinear frame 7. Accordingly, the third group lens holding frame 13 is positioned in the optical axis O direction with respect to the rectilinear frame 7.

  A cylindrical surface portion 13g is provided on the outer peripheral portion of the cylindrical portion 13d. The cylindrical surface portion 13g is a portion where a light shielding blade 8 described later is extrapolated so as to be rotatable around the cylindrical surface portion 13g. The central axis of the cylindrical surface portion 13g substantially coincides with the central axis of the sliding hole 13c. In the present embodiment, as shown in FIG. 6, the cylindrical surface portion 13g has a smaller outer diameter than other portions of the cylindrical portion 13d and is formed to have a predetermined length L1 in the axial direction.

  An operating lever 13f is erected from the outer peripheral portion of the cylindrical portion 13d toward the radially outer side. As shown in FIG. 11, the operation lever 13 f is provided so as to protrude to the outer peripheral side of the side surface portion 7 d through a through hole formed in the side surface portion 7 d of the rectilinear frame 7. The operating lever 13f is slidably engaged with a lens retracting cam groove carved on the inner peripheral surface of the cam frame 5. When the cam frame 5 disposed on the outer periphery of the rectilinear frame 7 rotates relative to the rectilinear frame 7 around the optical axis O, the third group lens holding frame 13 moves around the rotational axis 10. Rotate.

  The abutting portion 13 h abuts on a convex stopper 7 f provided on the flat surface portion 7 b of the rectilinear frame 7, so that the lens barrel 1 extends around the rotation axis 10 of the third lens group holding frame 13 in the extended state. It is a part for positioning. As shown in FIG. 4, the third group lens holding frame 13 is rotated from the state where the third group lens 23 is retracted from the optical axis O to the direction of advancement on the optical axis O as shown in FIGS. In the case where the lens optical axis of the third group lens 23 is substantially coincident with the optical axis O, the contact portion 13h contacts the stopper 7f.

  In the present embodiment, the contact portion 13h is provided at a position farther from the rotation shaft 10 than the lens holding portion 13a. In this way, by providing the contact portion 13h at a position away from the rotation shaft 10 in the radial direction, the influence of the dimensional error of each member on the positioning of the third lens group 23 in the extended state of the lens barrel 1 can be achieved. Can be small.

  The arm portion 13b is provided with an engaging portion 13e. The engaging portion 13e is a part that engages with a light shielding blade 8 described later and interlocks the light shielding blade 8 with the rotation of the third group lens holding frame 13. In the present embodiment, the engaging portion 13e has a convex shape that protrudes forward from the front surface of the arm portion 13b. More specifically, the engaging portion 13e has a cylindrical shape with a diameter D1. The engaging portion 13e is disposed at a position where the central axis is substantially parallel to the central axis of the sliding hole 13c and the central axis is separated from the central axis of the sliding hole 13c by a distance R3.

  Further, in the present embodiment, the third group lens holding frame 13 is urged in a direction to advance on the optical axis O by an urging member 9 having elasticity. That is, the urging member 9 urges the third group lens holding frame 13 in a direction in which the abutting portion 13 h of the third group lens holding frame 13 comes into contact with the stopper 7 f. In this embodiment, as an example, the urging member 9 is configured by a torsion spring wound around the rotation shaft 10.

  Thus, the biasing member 9 biases the third group lens holding frame 13 in the direction in which the abutting portion 13h abuts against the stopper 7f, thereby positioning the third group lens 23 in the extended state. Can be done without. The form of the urging member 9 is not limited to the torsion spring, and may be a plate spring or a coil spring.

  FIG. 7 is a view of the light shielding blade 8 as seen from the rear. As shown in FIG. 7, the light shielding blade 8 includes a cylindrical portion 8b, a light shielding portion 8a extending from the outer periphery of the cylindrical portion 8b, and a contact portion 8d.

  The cylindrical portion 8b is a substantially cylindrical portion in which a sliding hole 8c is formed on the outer periphery of the cylindrical surface portion 13g of the third group lens holding frame 13 with a predetermined gap. When the sliding hole 8c is fitted into the cylindrical surface portion 13g of the third group lens holding frame 13, the light shielding blade 8 is supported so as to be rotatable around the central axis of the cylindrical surface portion 13g. In other words, the light-shielding blade 8 is supported so as to be rotatable around a rotation axis 10 substantially parallel to the optical axis O with respect to the rectilinear frame 7.

  The thickness L2 of the cylindrical portion 8b in the central axis direction is set to a value smaller than the length L1 of the cylindrical surface portion 13g in the central axis direction by a predetermined value. As described above, since the cylindrical surface portion 13g has a smaller outer diameter than other portions of the cylindrical portion 13d, the sliding hole 8c is fitted to the cylindrical surface portion 13g of the third group lens holding frame 13, and the first When the sliding hole 13c of the third group lens holding frame 13 is fitted to the rotating shaft 10, as shown in FIG. 11, the cylindrical portion 8b includes a plane portion 7b and a cylindrical surface portion of the cylindrical portion 13d. A portion having an outer diameter larger than 13 g is sandwiched with a predetermined gap in the direction of the optical axis O. That is, in this state, the light shielding blade 8 is positioned in the optical axis O direction with respect to the rectilinear frame 7.

  As described above, in the lens barrel 1 of the present embodiment, the light blocking blade 8 is fitted into the outer periphery of the cylindrical surface portion 13g of the third group lens holding frame 13 with a gap, thereby holding the third group lens. The frame 13 and the light shielding blade 8 are supported so as to be rotatable around the rotation axis 10 with respect to the rectilinear frame 7. Therefore, in the present embodiment, the positioning accuracy of the third group lens holding frame 13 relative to the rectilinear frame 7 is fixed to the rectilinear frame 7 with the flat surface portion 7b, the tongue piece portion 7h and the stopper 7g provided on the rectilinear frame 7. It is only influenced by the rotating shaft 10.

  That is, in this embodiment, the rotation of the light shielding blade 8 and the variation in the shape and size of the light shielding blade 8 do not affect the positioning accuracy of the third group lens holding frame 13 with respect to the rectilinear frame 7. For this reason, in the present embodiment, the third lens group 23 retracted from the optical axis O in the retracted state can be accurately positioned and held in the extended state.

  The abutting portion 8d abuts on a convex stopper 7g provided on the flat surface portion 7b of the rectilinear frame 7, thereby positioning the light shielding blade 8 around the rotation axis 10 in the extended state of the lens barrel 1. It is a part of. As shown in FIG. 4, from the state where the light shielding blade 8 is retracted from the position overlapping the opening 7c of the rectilinear frame 7, the light shielding blade 8 is advanced to the position overlapping the opening 7c as shown in FIGS. When rotated, the contact portion 8d contacts the stopper 7g at a predetermined position.

  The light shielding portion 8a is a substantially flat plate-like portion that extends radially outward from the outer peripheral portion of the cylindrical portion 8b. The light shielding portion 8a is a region that does not obstruct the effective optical path of the third group lens 23 of the opening 7c when viewed from the optical axis O direction when the lens barrel 1 is extended, that is, when the shielding blade 8 is advanced. It has a shape that at least partially shields it.

  Specifically, in the present embodiment, as shown in FIG. 9, the light-shielding portion 8 a is third than the third-group lens holding frame 13 when viewed from the optical axis O direction when the lens barrel 1 is extended. It has a shape that shields the region of the opening 7c that exists in the direction in which the group lens holding frame 13 is retracted.

  An engaging portion 8e is provided in the light shielding portion 8a. The engaging portion 8 e is a portion for engaging the light shielding blade 8 with the rotation of the third group lens holding frame 13 by engaging with the engaging portion 13 e of the third group lens holding frame 13. In the present embodiment, the engaging portion 8e is a concave groove portion carved on the rear surface of the light shielding portion 8a.

  More specifically, the engaging portion 8e is a substantially arc-shaped groove having a radius R4 with the central axis of the sliding hole 8c as the center. The width D2 of the engaging portion 8e is larger than the diameter D1 of the engaging portion 13e of the third group lens holding frame 13 by a predetermined value. The radius R4 of the substantially arcuate engaging portion 8e is substantially the same as the separation distance R3 between the engaging portion 13e and the central axis of the sliding hole 13c.

  As shown in FIG. 9, when the lens barrel 1 is in the extended state, a predetermined gap is formed between the engaging portion 8e that is a groove and the engaging portion 13e that protrudes into the groove. In addition, one end of the engaging portion 8e, which is a groove, is formed. Therefore, the positioning of the light shielding blade 8 in the turning-out state in the extended state is performed by the contact portion 8d hitting the stopper 7g in the direction of advancement toward the opening portion 7c, and the direction of retreating from the opening portion 7c. This is performed by the engagement relationship between the engaging portion 8e and the engaging portion 13e. That is, the light-shielding blade 8 is positioned with a slight play in the rotation direction around the rotation shaft 10 in the extended state.

  In this way, when the lens barrel 1 is in the extended state, a gap is formed between the engaging portion 13e of the third group lens holding frame 13 and the engaging portion 8e of the light shielding blade 8. Thus, the engagement of the engaging portion 13e and the engaging portion 8e is prevented from affecting the positioning accuracy of the third lens group holding frame 13.

  In addition, the light shielding blade 8 having the above-described configuration is created by integral molding using, for example, a black synthetic resin. Moreover, in order to suppress the light reflectivity, it is preferable that an uneven shape is formed on the entire surface of the light shielding portion 8a.

  In the lens barrel 1 of the present embodiment having the above-described configuration, a part of the region that does not overlap the third group lens holding frame 13 in the opening 7c of the rectilinear frame 7 in the extended state is provided with the light shielding blade 8. It can be shielded by the light shielding portion 8a. Specifically, in the lens barrel 1 of the present embodiment, in the extended state, the third lens group holding frame 13 is retracted more than the third lens group holding frame 13 when viewed from the optical axis O direction. The area of the existing opening 7c is shielded by the light shielding part 8a.

  In the lens barrel 1, a retraction opening 7 e of the rectilinear frame 7 and a through hole 25 a of the shutter unit 25 are provided in the direction in which the third group lens holding frame 13 retreats when viewed from the optical axis O direction. ing. The retracting opening 7e and the through hole 25a are provided to form a space for accommodating the third group lens holding frame 13 in the retracted state.

  As shown by arrows A1 and A2 in FIG. 1, the retracting opening 7e and the through hole 25a may pass light rays unnecessary for image formation by the optical system member in the extended state. In the present embodiment, the light shielding blade 8 is positioned in front of the retracting opening 7e and the through hole 25a, and the light shielding blade 8 is a region in the direction in which the retracting opening 7e and the through hole 25a are positioned. Therefore, unnecessary light rays that pass through the retreat opening 7e and the through hole 25a are not generated.

  Therefore, in the lens barrel 1 of the present embodiment, the total length of the retracted lens barrel 1 can be shortened by retracting the third lens group 23 from the optical axis O in the retracted state, and in the extended state. In FIG. 5, it is possible to prevent generation of unnecessary light rays that pass through the opening 7e and the through hole 25a formed for retracting the third lens group 23, and it is possible to obtain high-quality image formation.

  The light shielding blade 8 does not interfere with the positioning of the third group lens holding frame 13 when the lens barrel 1 is in the extended state. For this reason, the lens barrel 1 of the present embodiment can accurately position the third group lens 23. As described above, the lens barrel 1 of the present embodiment can prevent unnecessary light from passing through and improve the lens positioning accuracy.

  Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and a lens mirror accompanying such a change. The cylinder is also included in the technical scope of the present invention.

  The lens barrel according to the present invention is not limited to the imaging apparatus described in the embodiment, but can be applied to a lens barrel of an electronic device having a photographing function, and can also be applied to a lens barrel of a film camera. is there.

1 lens barrel,
2 fixed frame,
3 Movement frame,
4 Rotating frame,
5 Cam frame,
7 Linear frame (holding member),
7a sliding shaft,
7b plane part,
7c opening,
7d side surface,
7e Retraction opening,
7f stopper,
7g stopper,
7h tongue piece,
8 Shading blade,
8a shading part,
8b cylindrical part,
8c sliding hole,
8d contact part,
9 biasing member,
10 pivot axis,
11 First lens group holding frame,
12 Second group lens holding frame,
13 Third lens group holding frame (retractable lens frame),
13a Lens holding part,
13b arms,
13c sliding hole,
13d cylindrical shape part,
13e engaging part,
13f actuating lever,
13g cylindrical surface,
13h contact part,
14 Fourth lens group holding frame,
21 first lens group,
22 Second lens group,
23 third lens group,
24 fourth lens group,
25 Shutter unit,
25a through hole,
25b through hole,
26 Image sensor,
27 Holding plate.

Claims (2)

An extended state in which a plurality of lenses are held and all the lenses are arranged on the optical axis, and a retractable lens composed of a part of the lenses is retracted from the optical axis and the light is more than in the extended state. a collapsed state having a reduced axial length, capable of changing a configured lens barrel, the
A holding member having an opening through which the optical axis passes;
The retractable lens is held and can be rotated around a rotation axis parallel to the optical axis fixed to the holding member, and when viewed from the direction along the optical axis, A retractable lens frame that is located in a region that overlaps the opening, and is supported so as to be relatively movable with respect to the holding member so as to retract from the opening in the retracted state;
It is disposed between the holding member and the retractable lens frame, is rotatable around the rotation axis, and when viewed from the direction along the optical axis, The retraction lens frame is shielded from the region located in the retraction direction, and in the retracted state, the retraction lens frame is retreated from the opening and moved to a position overlapping with the retraction lens frame. A light-shielding blade that is movably supported ,
The retractable lens frame and the light shielding blade have an engaging portion that engages with each other, and the light shielding blade moves around the rotation axis in conjunction with the movement of the retractable lens frame via the engaging portion. In the rotating lens barrel,
The pivot shaft is a columnar member provided between a pair of plane portions provided on the holding member and parallel to each other and perpendicular to the optical axis,
The retractable lens frame is slidably fitted to the outer periphery of the rotating shaft, and the outer peripheral shape has a cylindrical shape with the rotating shaft as a central axis, and one end of the cylindrical portion along the optical axis A cylindrical surface portion having an outer diameter smaller than that of the cylindrical shape portion provided on the cylindrical shape portion, and the cylindrical shape portion is arranged between the pair of flat surface portions when the cylindrical shape portion is moved along the rotation axis. It is regulated by being established,
The light-shielding blade includes a sliding hole that is slidably fitted to the outer periphery of the cylindrical surface portion, and a thickness in a direction along the optical axis of the portion where the sliding hole is formed is equal to that of the cylindrical surface portion. A lens barrel characterized by being thinner than a thickness in a direction along the optical axis . An urging member that urges the holding member in a direction to advance on the optical axis;
Positioning of the retractable lens frame around the rotation axis in the extended state is performed by the retractable lens frame being abutted against the holding member by the biasing force of the biasing member,
The engagement portion includes a gap between the engagement member and the blade member so that the blade member can rotate within a predetermined range around the rotation axis in the extended state. The lens barrel according to claim 1.

Images