JP2010014786A - Light-shielding member-supporting structure of lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-shielding member-supporting structure by which appropriate position control of a light-shielding member for intercepting unwanted light can be performed and which is constituted to be compact and simple. <P>SOLUTION: The light-shielding member-supporting structure of a lens barrel includes: a lens holding frame which holds a lens group; a straight advance guiding member which guides the lens holding frame to move to straight advance in an optical axis direction; a driving means which drives the lens holding member in the optical axis direction relative to the straight advance guiding member; the light-shielding member which is supported to move in the optical axis direction with the lens holding frame; and a light-shielding member movement regulation part which is provided between the straight advance guiding member and the light-shielding member, and regulates the movement of the light-shielding member with the lens holding member when the lens holding frame moves to go over a predetermined position in the optical axis direction relative to the straight advance guiding member, so as to change an interval with the lens group in the optical axis direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a support structure for a light shielding member whose position in the optical axis direction is controlled according to the situation in a lens barrel.

Some lens barrels include a light blocking member in the optical path so that unnecessary light does not enter the image plane side. The simplest type of light shielding member is fixed to a movable member such as a lens holding frame movable in the optical axis direction, and its position in the optical axis direction is controlled. By the way, depending on the configuration of the optical system, there is a case where it is required to change the position of the light shielding member with respect to the lens group in order to obtain an appropriate light shielding effect according to the change in focal length or to make the housing compact. . Patent Document 1 describes a support structure using a cam mechanism as a configuration for performing independent optical axis direction position control of a light shielding member (light shielding cylinder).
JP-A-9-33781

  By using a cam mechanism for the support structure of the light shielding member, fine position control of the light shielding member becomes possible, but on the other hand, there is a problem that the structure becomes complicated and hinders the compactness of the lens barrel. . SUMMARY OF THE INVENTION An object of the present invention is to provide a support structure for a light shielding member having a compact and simple configuration that can perform appropriate position control of a light shielding member for blocking unnecessary light.

  The present invention relates to a lens holding member that holds a lens group; a rectilinear guide member that guides the lens holding member so as to be linearly movable in the optical axis direction; drive means that moves the lens holding member in the optical axis direction with respect to the linear guide member A light-shielding member supported so as to be movable in the optical axis direction along with the lens holding member; and a lens holding member provided between the linear guide member and the light-shielding member, and the lens holding member in a predetermined position in the optical axis direction with respect to the linear guide member And a light shielding member movement restricting portion that restricts the movement of the light shielding member accompanying the lens holding member and changes the distance between the lens group in the optical axis direction.

  The light blocking member movement restricting portion is preferably configured as follows. The lens holding member has a linear groove in a direction parallel to the optical axis, and the linear guide member includes a guide key that can be moved relative to the linear groove in the optical axis direction. On the other hand, it is provided with a radially opposing portion that faces radially. Then, the guide key of the rectilinear guide member and the light shielding member are arranged on the facing surface of the radially opposing portion in a direction parallel to the optical axis, and engaged by relative movement of the rectilinear guide member and the shading member in the optical axis direction. The first engaging portion is provided, and movement of the light shielding member in the optical axis direction is restricted by the engagement of the first engaging portion.

  On the opposing surface of the guide key of the rectilinear guide member and the radially opposing portion of the light shielding member, the light shielding member moves in the optical axis direction relative to the rectilinear guide member in a direction opposite to the movement restricting direction by the first engaging portion. A second engagement portion that determines the end may be formed.

  As specific modes of the first and second engaging portions, the optical axis direction end surface of the groove portion formed on the opposing surface of the guide key of the linear guide member and the opposing surface of the radially opposing portion of the light shielding member It is preferable to form a combination with the radial projections provided in the groove and projecting in the groove, since the radial compactness can be achieved.

  Further, a separation limiting portion that determines a maximum separation position in the optical axis direction between the light shielding member and the lens group may be provided between the lens holding member and the light shielding member. When the separation limiting portion is configured by an optical axis direction end surface of a linear groove formed in the lens holding member in a direction parallel to the optical axis, and a radial protrusion provided in the light shielding member and fitted in the linear groove, As in the case of the second engaging portion, it is preferable because the radial direction can be reduced.

  The present invention is particularly suitable for position control of the light shielding member in the zoom range of the zoom lens barrel, and the movement of the light shielding member by the light shielding member movement restricting unit during the focal length changing operation between the wide end and the tele end. Configured to be regulated.

  The present invention also provides a lens holding member that holds the lens group; a linear guide member that guides the lens holding member so as to move linearly in the optical axis direction; and a drive that moves the lens holding member in the optical axis direction with respect to the linear guide member. Means; a light shielding member supported so as to be movable in the optical axis direction along with the lens holding member; and a movement of the light shielding member forwardly in the optical axis direction relative to the linear guide member provided between the linear guide member and the light shielding member And a second engaging part for restricting movement in the rear in the optical axis direction.

  According to the present invention described above, the position of the light shielding member with respect to the lens holding member (lens group) using the movement restricting portion provided between the linear guide member that linearly guides the lens holding member in the optical axis direction and the light shielding member. Since the control is performed, a complicated cam structure or the like is unnecessary, and a light shielding member support structure having a compact and simple configuration can be obtained.

  With reference to FIGS. 1 to 5, a schematic structure of a zoom lens barrel 70 provided with a support structure for a light shielding member according to the present invention will be described. The imaging optical system of the zoom lens barrel 70 includes, in order from the object (subject) side, a first lens group LG1, a second lens group LG2, a shutter blade S that also serves as an aperture, a third lens group LG3, a low-pass filter 25, and an imaging element. In the following description, the optical axis direction means a direction parallel to the optical axis O of the photographing optical system.

  The low-pass filter 25 and the image sensor 71 are unitized and fixed to the image sensor holder 23, and the image sensor holder 23 is fixed to the rear portion of the housing 22. A zoom motor 150 and an AF motor 160 are supported outside the housing 22.

  The third group lens frame 51 that holds the third lens group LG3 is supported so as to be movable in the optical axis direction with respect to the housing 22, and is driven by the AF motor 160.

  A cam ring 11 is supported inside the housing 22. The cam ring 11 is rotated by the driving force of the zoom motor 150 and moves in the optical axis direction while rotating from the lens barrel storage state (FIG. 3) to the wide end (FIG. 4). In the zoom photographing region between the telephoto ends (FIG. 5), the zoom is rotated at a fixed position in the optical axis direction. More specifically, as shown in FIGS. 3 to 5, the cam ring 11 is provided with a gearing portion 11a at a rear end portion in the optical axis direction, and a guide projection 11b is projected on the gearring 11a. The gearing portion 11 a meshes with a zoom gear (not shown) rotated by the zoom motor 150, and the guide protrusion 11 b is slidably engaged with a cam ring guide groove 22 a formed on the inner peripheral surface of the housing 22. Match. The cam ring guide groove 22a has a spiral groove portion rearward in the optical axis direction and an annular groove portion centered on the photographing optical axis O forward in the optical axis direction. The cam ring guide groove 22a is in the lens barrel storage state and the photographing state (wide end). In the meantime, the guide protrusion 11 b is guided by the spiral groove portion of the cam ring guide groove 22 a, and the cam ring 11 moves in the optical axis direction while rotating with respect to the housing 22. Specifically, the cam ring 11 advances forward in the optical axis direction (object side) while rotating when the lens barrel storage state is changed to the photographing state, and conversely when the lens barrel storage state is changed from the photographing state, While rotating, it moves backward in the optical axis direction. Further, in the zoom range from the wide end to the tele end, the guide projection 11b is guided by the annular groove portion of the cam ring guide groove 22a, and the cam ring 11 does not change the position in the optical axis direction with respect to the housing 22, and the optical axis direction. It is rotated at a fixed position.

  The first feed cylinder 13 and the straight guide ring 10 are supported with the cam ring 11 in between. The first feeding cylinder 13 and the rectilinear guide ring 10 are each guided in a straight line with respect to the housing 22 in the optical axis direction, and can be relatively rotated with respect to the cam ring 11 and move together in the optical axis direction. Are combined.

  The rectilinear guide ring 10 guides the second group lens moving frame 8 so that it can move relative to the optical axis. Inside the second group lens moving frame 8, a second group lens holding frame 2 that holds the second lens group LG2 and a shutter block 100 that holds the shutter blades S are supported. Further, the first feeding cylinder 13 guided linearly in the optical axis direction with respect to the housing 22 further guides the second feeding cylinder 12 so as to be relatively movable in the optical axis direction. A first lens group LG <b> 1 is supported inside the second feeding cylinder 12 via a first group lens holding frame 1.

  The second feeding cylinder 12 has a first group cam follower CF1 protruding in the inner diameter direction, and the first group cam follower CF1 is slidably fitted in a first group control cam groove CG1 formed on the outer peripheral surface of the cam ring 11. is doing. Since the second feeding cylinder 12 is guided linearly in the direction of the optical axis via the first feeding cylinder 13, when the cam ring 11 rotates, the second feeding cylinder 12, i.e., the first feeding cylinder 12, according to the shape of the first group control cam groove CG1. The lens group LG1 moves along a predetermined locus in the optical axis direction.

  The second group cam follower CF2 provided on the outer peripheral surface of the second group lens moving frame 8 is engaged with the second group control cam groove CG2 formed on the inner peripheral surface of the cam ring 11. Since the second group lens moving frame 8 is linearly guided in the optical axis direction via the straight guide ring 10, when the cam ring 11 rotates, the second group lens moving frame 8, i.e., the first group moving frame 8 according to the shape of the second group control cam groove CG2. The two lens group LG2 moves along a predetermined locus in the optical axis direction.

  A group biasing spring 27 made of a compression spring is inserted between the second group lens moving frame 8 and the second feeding cylinder 12, and the second group lens moving frame 8 and the second feeding cylinder 12 are separated from each other. Is being energized.

  The zoom lens barrel 70 having the above structure operates as follows. In the lens barrel storage state shown in FIGS. 1 and 3, the length of the optical system in the optical axis direction (from the surface on the object side of the first lens group LG1 to the imaging element) as compared to the imaging states shown in FIGS. 71) (distance to the imaging surface) is shortened. When a transition signal to the photographing state in this lens barrel storage state (for example, a main switch provided in a camera on which the zoom lens barrel 70 is mounted) is input, the zoom motor 150 is driven in the lens barrel feeding direction. The cam ring 11 is fed forward in the optical axis direction while rotating. The rectilinear guide ring 10 and the first feed cylinder 13 move forward together with the cam ring 11. When the cam ring 11 rotates, on the inner side, the second group lens moving frame 8 guided linearly through the straight guide ring 10 is predetermined in the optical axis direction due to the relationship between the second group cam follower CF2 and the second group control cam groove CG2. It is moved by the trajectory. Further, when the cam ring 11 rotates, the second feeding cylinder 12 guided linearly through the first feeding cylinder 13 on the outside of the cam ring 11 is related to the first group cam follower CF1 and the first group control cam groove CG1. Is moved along a predetermined locus in the optical axis direction.

  That is, the first lens group LG1 and the second lens group LG2 are fed out from the lens barrel retracted state by the former moving amount of the cam ring 11 with respect to the housing 22 and the second feeding cylinder 12 with respect to the cam ring 11, respectively. The latter is determined as the sum of the amount of forward movement of the cam ring 11 relative to the housing 22 and the amount of cam extension of the second group lens moving frame 8 relative to the cam ring 11. Zooming is performed by moving the first lens group LG1 and the second lens group LG2 along the photographing optical axis O while changing the air interval between them. When the lens barrel is extended from the housed state, first, the wide end extended state shown in FIG. 4 is obtained. When the zoom motor 150 is further driven in the lens barrel extending direction, the tele end extended state shown in FIG. In the zoom region between the tele end and the wide end, the cam ring 11 rotates at the above-mentioned fixed position and does not advance or retreat in the optical axis direction. When a storage state transition signal (for example, turning off the main switch of the camera) is input, the zoom motor 150 is driven in the lens barrel storage direction, and the zoom lens barrel 70 is retracted in the opposite manner to the above-described extension operation. I do.

  Further, a barrier blade 104 capable of opening and closing the front of the first lens group LG1 is provided at the front end portion of the second feeding cylinder 12, and the barrier blade 104 is closed when the lens barrel is housed, so that the shooting state is restored. The barrier blade 104 is opened according to the feeding operation.

  The third lens group frame 51 that supports the third lens group LG3 is moved back and forth in the optical axis direction by the AF motor 160 independently of the driving of the first lens group LG1 and the second lens group LG2 by the zoom motor 150 described above. Can be made. When the optical system is in the zoom range from the wide end to the tele end, the third lens group LG3 is moved in the optical axis direction by driving the AF motor 160 according to the subject distance information obtained by the distance measuring means. Move to perform focusing.

  The zoom lens barrel 70 is provided with a light blocking member 15 at the rear portion of the second group lens moving frame (lens holding member) 8 for preventing unnecessary light from entering the image sensor 71. Hereinafter, the support structure of the light shielding member 15 will be described.

  As shown in FIG. 9, the rectilinear guide ring (straight guide member) 10 has an annular rear end ring-shaped portion 10a centered on the photographing optical axis O, and 3 projects in the outer diameter direction from the rear end ring-shaped portion 10a. One guide projection 10b and a plurality of rotation guide claws 10c provided intermittently in the circumferential direction on the front portion of the rear end ring-shaped portion 10a. Each of the three guide protrusions 10b is slidably fitted into a rectilinear guide groove 22b (FIGS. 3 to 5) formed on the inner peripheral surface of the housing 22 and parallel to the photographic optical axis O. The guide ring 10 is guided straight in the optical axis direction. The rotation guide claw 10c is restricted from moving in the optical axis direction with respect to the rotation guide claw 11c (FIGS. 3 to 5) formed on the inner peripheral surface near the rear end of the cam ring (lens holding member driving means) 11. The linear guide ring 10 is coupled to the cam ring 11 so that the relative position in the optical axis direction is unchanged and relative rotation is possible. Yes. Further, three rectilinear guide keys 10d protrude from the rear end ring-shaped portion 10a toward the front in the optical axis direction. Each of the rectilinear guide keys 10d is a partial cylindrical portion that forms a part of a cylindrical body with the photographing optical axis O as the center.

  As shown in FIGS. 6 and 7, the second group lens moving frame 8 has a cylindrical portion 8a with a second group cam follower CF2 projectingly formed on the outer peripheral surface, and on the cylindrical portion 8a in the optical axis direction. Three linear guide grooves (linear grooves) 8b, which are linear grooves, are formed. Due to the fitting relationship between the three rectilinear guide grooves 8b and the three rectilinear guide keys 10d of the rectilinear guide ring 10, the second group lens moving frame 8 is guided linearly in the optical axis direction. The second group lens moving frame 8 has an annular inner flange portion 8c substantially orthogonal to the photographing optical axis O on the inner peripheral surface near the front end portion of the cylindrical portion 8a, and on the inner diameter side of the inner flange portion 8c, A second group holding ring portion 8d (FIGS. 14 to 19) that changes its position in the optical axis stepwise as it approaches the photographing optical axis O is formed. The second group holding ring portion 8d and the second group lens holding frame 2 are formed. The second lens group LG2 is held in between. A shutter block storage space 8e is formed at the rear of the inner flange portion 8c and the second group holding ring portion 8d in the second group lens moving frame 8.

  In the shutter block storage space 8e, a shutter block 100 whose appearance is shown in FIGS. 6 and 7 is supported so as to be movable in the optical axis direction. As shown in FIG. 7, a front guide pin 8 f protrudes rearward in the optical axis direction at the inner flange portion 8 c of the second group lens moving frame 8, and a front pin insertion hole formed in the shutter holding frame 100 a of the shutter block 100. 100b is inserted. The shutter holding frame 100a is formed with a rear pin insertion hole 100c positioned coaxially with the front pin insertion hole 100b, and the rear guide pin 5a of the shutter stopper member 5 is inserted into the rear pin insertion hole 100c. The shutter stopper member 5 is fixed to a stopper mounting recess 8g (FIG. 7) provided at the rear portion of the second group lens moving frame 8 by a fixing screw 32. In this fixed state, the shutter block 100 is guided so as to be linearly movable in the optical axis direction by the relationship between the front and rear pin insertion holes 100b and 100c formed in the shutter holding frame 100a and the front and rear guide pins 8f and 5a. The member 5 is provided with a backward movement restricting portion 5b for restricting the backward movement thereof. The shutter block 100 is urged toward the rear moving end side approaching the rear movement restricting portion 5b by a shutter block urging spring 30 formed of a compression coil spring. A rear cover plate 100d for closing the rear portion of the shutter blade S is attached to the rear surface side of the shutter holding frame 100a.

  As shown in FIG. 8, the light shielding member 15 includes a light shielding plate support frame 16 and a light shielding plate 17. The light shielding plate support frame 16 has an annular portion 16a surrounding the photographing optical axis O, and a thin light shielding plate 17 is attached to the front portion of the annular portion 16a. In the center of the light shielding plate 17, an opening 17a for allowing light for photographing to pass is formed. Three first support keys (radially facing portions) 16b and second support keys 16c are provided at different positions in the circumferential direction from the outer peripheral portion of the annular portion 16a of the light shielding plate support frame 16 toward the front in the optical axis direction. It is protruding. Each first support key 16b is inserted into three light shielding member support grooves (straight grooves) 8h formed in the second group lens moving frame 8, and each second support key 16c is inserted in the second group lens moving frame 8. It is inserted into three light shielding member support grooves 8i (FIG. 7) formed on the peripheral surface side. Each of the light shielding member support grooves 8h and 8i is a long groove in a direction parallel to the photographing optical axis O. Of these, the light-shielding plate support frame 16 is guided in a straight line so as to be movable relative to the second-group lens moving frame 8 in the optical axis direction by the sliding relationship between the first support key 16b and the light-shielding member support groove 8h. It is also possible to guide the light shielding plate support frame 16 straight by other parts such as the second support key 16c and the light shielding member support groove 8i.

  As shown in FIGS. 14 to 19, the annular portion 16 a and the light shielding plate 17 of the light shielding plate support frame 16 are located behind the rear cover plate 100 of the shutter block 100, and the first support of the light shielding plate support frame 16 is provided. The key 16b and the second support key 16c extend forward in the optical axis direction through the outside of the shutter block 100. Three first support key insertion recesses 100e are formed on the outer peripheral portion of the shutter holding frame 100a at circumferential positions corresponding to the three light shielding member support grooves 8h of the second group lens moving frame 8, and support three light shielding members. Three second support key insertion recesses 100f are formed at circumferential positions corresponding to the grooves 8i. Each of the three first support keys 16b of the light shielding plate support frame 16 protrudes forward of the shutter block 100 through the first support key insertion recess 100e and is inserted into the light shielding member support groove 8h. Similarly, each of the three second support keys 16c of the light shielding plate support frame 16 protrudes forward of the shutter block 100 through the second support key insertion recess 100f and is inserted into the light shielding member support groove 8i.

  As shown in FIGS. 6 and 7, in the second group lens moving frame 8, the three light shielding member support grooves 8 h into which the first support keys 16 b of the light shielding plate support frame 16 are inserted are respectively rectilinear guides of the rectilinear guide ring 10. It communicates with the bottom (inner diameter side) of the three rectilinear guide grooves 8b into which the key 10d is inserted, and the light shielding member support groove 8h located on the inner diameter side is more than the rectilinear guide groove 8b located on the outer diameter side. It is narrow. Further, the second group lens moving frame 8 communicates with the outer diameter side of three light shielding member support grooves 8i into which the second support keys 16c of the light shielding plate support frame 16 are inserted (through in the radial direction), A sub control groove (straight groove) 8j is formed. The sub-control groove 8j is a long groove in the optical axis direction that is narrower than the light shielding member support groove 8h, and the front end and the rear end in the optical axis direction are closed.

  As shown in FIG. 8, on the outer peripheral surface of each first support key 16b in the light shielding plate support frame 16, two front position control protrusions (second engagement portions, A radial projection) 16d and one rear position control projection (light-shielding member movement restricting portion, first engagement portion, radial projection) 16e are provided in a projecting manner. The two front position control protrusions 16d are spaced apart from each other in the width direction of the first support key 16b, and each of the front position control protrusions 16d has a quadrangular prism shape. The rear position control protrusion 16e has a standing wall surface 16e-1 that is positioned substantially at the center in the width direction of the first support key 16b and faces forward in the optical axis direction. Further, as shown in FIG. 8, on the outer peripheral surface of the light shielding plate support frame 16 near the front end portion of each second support key 16c, a sub-control projection (separation limiting portion) 16f is projected. The sub-control protrusion 16f has a standing wall surface 16f-1 that is positioned substantially at the center in the width direction of the first support key 16b and faces rearward in the optical axis direction.

  On the inner peripheral surface of the rectilinear guide key 10d of the rectilinear guide ring 10, a wide light shielding member control groove 10e and a narrow rear communication groove 10f communicating with the rear of the light shielding member control groove 10e are formed. The light shielding member control groove 10e is a long groove formed with a constant width from the vicinity of the front end portion of the linear guide key 10d toward the rear in the optical axis direction, and two front openings 10g spaced apart in the groove width direction at the front end portion. In addition, a position control projection (light shielding member movement restricting portion, first engaging portion) 10h sandwiched between the two front openings 10g is formed. On the position control projection 10h, a standing wall surface 10h-1 facing rearward in the optical axis direction is formed. At the rear end of the light shielding member control groove 10e, there are two movement restricting surfaces (second engaging portions) 10i positioned on the extension of the two front openings 10g in the optical axis direction and facing forward in the optical axis direction. Is formed. In the light-shielding member control groove 10e, the standing wall surface 10h-1 of the position control projection 10h constitutes an end face in the optical axis direction front, and the movement restricting surface 10i constitutes an end face in the rear in the optical axis direction. The surfaces (10h-1, 10i) are different from each other in the groove width direction. The rear communication groove 10f is located on the extension of the position control projection 10h in the optical axis direction, and the front end portion of the rear communication groove 10f communicates between the two movement restriction surfaces 10i.

  As shown in FIG. 10, the inner peripheral surface of the rectilinear guide key 10d of the rectilinear guide ring 10 and the shading plate support frame in a state where the second group lens moving frame 8, the rectilinear guide ring 10, the light shielding member 15, and the shutter block 100 are combined. The front position control protrusion 16d on the first support key 16b faces the front opening 10g on the linear guide key 10d side and the optical axis of the movement restricting surface 10i. The rear position control protrusion 16e is positioned on the direction extension, and is positioned on the optical axis direction extension of the rear communication groove 10f and the position control protrusion 10h. In other words, the radial positions of the front position control projection 16d and the rear position control projection 16e protruding on the first support key 16b are set so that the light shielding member control groove 10e and the rear communication groove 10f of the linear guide key 10d of the linear guide ring 10 are provided. It overlaps with the radial position. Further, the sub control projection 16 f provided on the second support key 16 c of the light shielding plate support frame 16 is positioned in the sub control groove 8 j of the second group lens moving frame 8. The position of the light shielding plate support frame 16 in the optical axis direction relative to the second group lens moving frame 8 is controlled by the engagement relationship between these protrusions and grooves, and the details will be described mainly with reference to FIG. 11 to 13, the light shielding plate support frame 16 overlaps with the second group lens moving frame 8 and the rectilinear guide ring 10 and is not shown with a broken line but is shown with a solid line.

  11, 14, and 15 show the light blocking member support structure when the zoom lens barrel 70 is housed. In the lens barrel storage state, the group lens frame 51 is located close to the back of the light shielding plate 17, and further retreat of the light shielding member 15 is restricted. Further, the rear cover plate 100d of the shutter block 100 is located on the front side of the light shielding plate 17, and the forward movement of the light shielding member 15 is also restricted. Further, the shutter block 100 is positioned at the front moving end (close position to the inner flange portion 8c) in the shutter block storage space 8e.

  In the lens barrel storage state, the front position control protrusion 16d provided on the light shielding plate support frame 16 and the rear position are determined by the mutual positional relationship of the second group lens moving frame 8, the linear guide ring 10, the light shielding member 15, and the shutter block 100. Each of the control protrusion 16e and the sub control protrusion 16f is held at the position shown in FIG. First, the two front position control protrusions 16d on the first support key 16b are located in the vicinity of the front opening 10g in the light shielding member control groove 10e of the linear guide ring 10, and the rear position control protrusion 16e is formed of the light shielding member control groove. 10e is positioned slightly in front of the movement restricting surface 10i (see FIG. 14). The sub control protrusion 16f on the second support key 16c is positioned near the front end portion in the sub control groove 8j of the second group lens moving frame 8 (see FIG. 15).

  When the zoom lens barrel 70 is extended from the lens barrel storage state to the photographing state, the cam ring 11 moves forward in the optical axis direction while rotating, and the rectilinear guide ring 10 also moves forward in the optical axis direction together with the cam ring 11. Moved. Further, the second group lens moving frame 8 takes an image by moving the cam ring 11 itself forward while changing the position in the optical axis direction within the cam ring 11 by the relationship between the second group cam follower CF2 and the second group control cam groove CG2. It is moved forward with respect to the element 71. When the second group lens moving frame 8 is moved forward, there is no restriction by the members behind the second group lens moving frame 8 (such as the third group lens frame 51 and the image sensor holder 23). By the urging force, the shutter stopper member 5 is retracted in the shutter block storage space 8e until it contacts the rearward movement restricting portion 5b. Then, as shown in FIGS. 16 and 17, the light shielding member 15 is pushed by the shutter block 100 and relatively moved rearward with respect to the second group lens moving frame 8, and the second lens group LG2 and the light shielding member 15 (light shielding) The distance between the plates 17) in the optical axis direction is larger than that when the lens barrel is stored.

  As described above, when the zoom lens barrel 70 is extended from the housed state to the photographing state, first, the wide end (FIG. 4) of the zoom range is obtained. As can be seen from FIG. 4, at the wide end, the first lens group LG1 is extended largely forward with respect to the image plane (imaging element 71), whereas the forward extension amount of the second lens group LG2 is small. The distance between the second lens group LG2 and the third lens group LG3 is narrow. Further, the third lens group LG3 is moved in the approaching direction to the second lens group LG2 by the focusing operation by the AF motor 160. For this reason, it is necessary to hold the light shielding member 15 positioned behind the second lens group LG2 at a position close to the second lens group LG2 to prevent interference with the third lens group LG3.

  FIGS. 12, 16, and 17 show the light blocking member support structure at the wide end. As can be seen from these drawings, in the mutual positional relationship between the rectilinear guide ring 10 and the light shielding member 15 at the wide end, the two front position control protrusions 16d on the first support key 16b of the light shielding plate support frame 16 have the rectilinear guide ring. The rear position control projection 16e enters the rear communication groove 10f and is located near the rear end thereof, being positioned close to the movement restricting surface 10i in the ten light shielding member control grooves 10e. Further, due to the mutual positional relationship between the second group lens moving frame 8 and the light shielding member 15, the sub control projection 16 f on the second support key 16 c is positioned near the center in the longitudinal direction of the sub control groove 8 j of the second group lens moving frame 8. Is done. In this state, the light of the light shielding member 15 with respect to the second group lens moving frame 8 and the rectilinear guide ring 10 is obtained by the engagement of the front position control projection 16 d provided on the shading plate support frame 16 and the movement restricting surface 10 i of the rectilinear guide ring 10. Since the rearward movement in the axial direction is restricted, the light shielding member 15 can be reliably held at a position where it does not interfere with the third lens group LG3.

  When the focal length is changed from the wide end to the tele end, as shown in FIG. 5, the second lens group LG2 moves forward in the optical axis direction and approaches the first lens group LG1. Thereby, there is no possibility of interference between the rear third lens group LG3 and the light shielding member 15, but on the other hand, as the distance between the second lens group LG2 and the third lens group LG3 is increased, the second lens group LG3 and FIG. The internal reflection of the lens barrel as shown by the dotted line IR is likely to occur. The position of the light shielding member 15 is controlled as follows in order to prevent such inner surface reflection and prevent the unnecessary light from entering the image sensor 71.

  As described above, at the time of the operation from the wide end to the tele end, the cam ring 11 is rotated at a fixed position without changing the position in the optical axis direction, and the straight guide that the cam ring 11 and the relative position in the optical axis direction are coupled invariably. The ring 10 also does not change its position in the optical axis direction. On the other hand, according to the rotation of the cam ring 11, the second group lens moving frame 8 is linearly moved forward in the optical axis direction by the relationship between the second group cam follower CF2 and the second group control cam groove CG2. The light shielding member 15 is moved forward along with the second group lens moving frame 8 by a frictional force acting between the support keys 16b and 16c of the light shielding plate 16 and the light shielding member support grooves 8h and 8i on the second group lens moving frame 8 side. It is drawn out to. Then, the front position control projection 16d and the rear position control projection 16e of the light shielding plate support frame 16 are relatively forward with respect to the light shielding member control groove 10e and the rear communication groove 10f of the linear guide ring 10 whose position in the optical axis direction does not change. Move to. Specifically, the rear position control protrusion 16e located near the rear end of the rear communication groove 10f at the wide end returns again into the light shielding member control groove 10e and is positioned close to the movement restricting surface 10i at the wide end. The forward position control protrusion 16d that has been moved moves toward the front end of the light shielding member control groove 10e. When the forward movement of the light shielding member 15 with respect to the linear guide ring 10 is continued with the movement toward the telephoto end, the two front position control projections 16d are separated from the light shielding member control groove 10e forward through the front opening 10g. (FIGS. 13 and 18). In addition, the rear position control protrusion 16e located at the center in the width direction of the first support key 16b has a standing wall surface with respect to the standing wall surface 10h-1 of the position control protrusion 10h located at the center in the width direction of the light shielding member control groove 10e. 16e-1 is brought into contact (FIGS. 13 and 18). The forward movement of the light shielding member 15 is restricted by the contact of the rear position control protrusion 16e with the position control protrusion 10h. As a result, the distance in the optical axis direction between the light shielding plate 17 of the light shielding member 15 whose forward movement is restricted and the second lens group LG2 held by the second lens group moving frame 8 that continues to move forward is increased.

  FIGS. 13, 18 and 19 show the light shielding member support structure in a state where the zoom lens barrel 70 reaches the telephoto end. As described above, the standing wall surface 16e-1 of the rear position control projection 16e on the first support key 16b abuts against the standing wall surface 10h-1 of the position control projection 10h to restrict the forward movement of the light shielding plate support frame 16; As a result, the light shielding plate 17 of the light shielding member 15 is located rearward from the second lens group LG2. As can be seen from FIG. 18 and FIG. 19, the light shielding plate 17 is positioned rearward from the second lens group LG2 in this way, so that the inner surface of the lens barrel (particularly a straight guide) passes through the second lens group LG2. The light beam going toward the inner peripheral surface of the key 10d can be reliably blocked by the light shielding plate 17. That is, it is possible to prevent unnecessary lens barrel inner surface reflected light toward the image sensor 71 and obtain high image quality.

  However, the light shielding member 15 at the tele end may not be positioned rearward with respect to the second lens group LG2, and the second light shielding member 15 blocks the unnecessary light while blocking the unnecessary light. It is also necessary to control (limit) the maximum separation position in the optical axis rearward direction with respect to the lens group LG2. At the wide end, the rearward movement of the light shielding member 15 with respect to the rectilinear guide ring 10 is restricted by the relationship between the front position control projection 16d in the light shielding plate support frame 16 and the movement restricting surface 10i of the rectilinear guide ring 10, but FIG. As shown in FIG. 18, at the tele end, the front position control projection 16d is detached forward from the light shielding member control groove 10e and is not involved in the position control of the light shielding plate support frame 16 in the optical axis direction. Instead, at the tele end, as shown in FIGS. 13 and 19, the standing wall surface 16f-1 of the sub-control projection 16f on the second support key 16c is a rear end surface (separation limiting portion) where the sub-control groove 8j is closed. ) Is located close to 8j-1, and due to the relationship between the sub-control projection 16f and the rear end surface 8j-1 of the sub-control groove 8j, the light-shielding plate support frame 16 moves backward relative to the second group lens moving frame 8. Be regulated. For example, even when a moving force in the rearward direction of the optical axis acts on the light-shielding plate support frame 16 by some external force, the standing wall surface 16f-1 of the sub-control projection 16f contacts the rear end surface 8j-1 of the sub-control groove 8j. By attaching, the backward movement of the light shielding member 15 is regulated.

  Conversely, in the transition from the tele end to the wide end, the second group lens moving frame 8 moves rearward in the optical axis direction, and the second lens group LG2 is separated from the first lens group LG1. When the second group lens moving frame 8 is retracted to some extent, the rear cover plate 100d of the shutter block 100 comes into contact with the light shielding plate 17, and thereafter the light shielding member 15 is retracted together with the second group lens moving frame 8 and the shutter block 100. By the backward movement of the light shielding member 15, the rear position control projection 16e on the first support key 16b moves away from the position control projection 10h and moves rearward in the light shielding member control groove 10e, and the two front position control projections 16d move forward. The light enters the light shielding member control groove 10e through the opening 10g. Further, the sub-control projection 16f on the second support key 16c is separated from the rear end surface 8j-1 of the sub-control groove 8j and changes its position in the sub-control groove 8j relatively forward (FIGS. 12 and 12). 17).

  In the transition from the wide end to the retracted state, the linear guide ring 10 moves rearward in the optical axis direction together with the cam ring 11, and accordingly, the second group lens moving frame 8 also moves rearward. Then, the annular portion 16a of the light shielding plate support frame 16 comes into contact with the restriction projection 23a (FIGS. 4 and 5) provided on the image sensor holder 23, and the backward movement of the light shielding member 15 and the shutter block 100 is restricted. Even after the light blocking member 15 and the shutter block 100 are retracted, the second group lens moving frame 8 continues to move. As a result, as shown in FIGS. 14 and 15, the urging force of the shutter block urging spring 30 is resisted. The position of the shutter block 100 in the shutter block storage space 8e changes relatively forward. In addition, the light shielding plate 17 and the second lens group LG2 are closer to each other in the optical axis direction than in the wide end, and in the retracted state, the light shielding plate 17 is closer to the rear end of the second lens group LG2.

  As described above, in the zoom lens barrel 70 of the present embodiment, when the distance between the second lens group LG2 and the third lens group LG3 in the optical axis direction is wide (tele end), the light is blocked behind the second lens group LG2. Since the position of the member 15 is controlled so as to increase the distance between the second lens group LG2 and the optical axis direction, unnecessary reflection light on the inner surface of the lens barrel can be effectively prevented. The position control of the light shielding plate support frame 16 in the optical axis direction is performed by controlling the position control projection 10h (standing wall surface) in the light shielding member control groove 10e formed in the linear guide ring 10 for guiding the second group lens moving frame 8 linearly. 10h-1) and the rear position control protrusion 16e (standing wall surface 16e-1) on the first support key 16b that supports the light shielding member 15 with respect to the second group lens moving frame 8 are engaged. The configuration is simpler than that in which the position of the light shielding member is controlled by a complicated cam mechanism or the like, and the effects of downsizing the lens barrel and reducing the manufacturing cost can be obtained.

  In addition to the rear position control projection 16e and the position control projection 10h that restrict the forward movement of the light shielding plate support frame 16 and increase the distance in the optical axis direction with respect to the second lens group LG2 when moving to the telephoto end, the light shielding member 15 Is located at an approach position with respect to the second group lens group LG2 (that is, at the wide end), the front position control projection 16d and the movement restricting surface 10i are provided as parts for restricting the rearward movement of the light shielding member 15, and the light shielding member 15 has two groups. A sub control projection 16f and a sub control groove 8j (rear end face 8j-1) are provided as parts for restricting the rearward movement of the light shielding plate support frame 16 when the lens group LG2 is at a position away from the lens group LG2 (ie, at the tele end). . As described above, by restricting the rearward movement of the light blocking member 15 at the wide end, it is possible to prevent interference with the third lens group LG3. At the tele end, by preventing excessive movement of the light shielding member 15 in the direction away from the second lens group LG2, it is possible to block only unnecessary rays and obtain an optimum light shielding effect. These portions that restrict the rearward movement of the light shielding member 15 are also provided on the projections (front position control projection 16d and sub control projection 16f) provided on the support keys 16b and 16c of the light shielding plate support frame 16 and the second group lens movement. Since the optical axis direction end surface of the groove formed in the frame 8 and the linear guide ring 10 (the movement restricting surface 10i of the light shielding member control groove 10e and the rear end surface 8j-1 of the sub control groove 8j) is configured, the configuration is simple. Therefore, it is possible to prevent the zoom lens barrel 70 from becoming large.

  As mentioned above, although this invention was demonstrated based on illustration embodiment, this invention is not limited to this embodiment. For example, in the embodiment, in the zoom range between the wide end and the tele end of the zoom lens barrel 70, the distance between the second lens group LG2 and the light shielding plate 17 in the optical axis direction is changed. The present invention can also be applied to a light shielding member support structure that changes the position of the light shielding member in the optical axis direction with respect to the lens group between the storage state of the lens barrel and the photographing state. That is, zooming is not performed by assuming that FIGS. 12 and 16 showing the wide end in the embodiment correspond to the lens barrel storage state and FIGS. 13 and 18 showing the tele end correspond to the photographing state. It is also established as a single focus lens.

It is an external appearance perspective view of the storage state of the zoom lens barrel to which the present invention is applied. It is an external appearance perspective view of the photographing state of the zoom lens barrel. It is sectional drawing of the accommodation state of the zoom lens barrel. It is sectional drawing in the wide end of the zoom lens barrel. It is sectional drawing in the tele end of the zoom lens barrel. It is a front perspective view of a 2nd group lens moving frame and a shutter block. It is a back perspective view of a 2nd group lens moving frame and a shutter block. It is a front perspective view of the light-shielding frame and light-shielding plate which comprise a light-shielding member. It is a front perspective view of a rectilinear guide ring. It is a front perspective view of the assembled state of the second group lens moving frame, shutter block, light shielding member, and linear guide ring. It is an expanded top view which shows the light shielding member support structure in the accommodation state of a zoom lens barrel. It is an expanded top view which shows the light-shielding member support structure in the wide end of a zoom lens barrel. It is an expanded top view which shows the light-shielding member support structure in the tele end of a zoom lens barrel. FIG. 12 is a cross-sectional view showing a relationship among a second group lens moving frame, a shutter block, a light shielding member, a rectilinear guide ring, and a third group lens frame at a position along the line A1-A1 in FIG. FIG. 12 is a cross-sectional view illustrating a relationship among a second group lens moving frame, a shutter block, a light blocking member, a straight guide ring, and a third group lens frame at a position along line B1-B1 in FIG. FIG. 13 is a cross-sectional view illustrating a relationship among a second group lens moving frame, a shutter block, a light shielding member, a rectilinear guide ring, and a third group lens frame at a position along the line A2-A2 of FIG. FIG. 13 is a cross-sectional view illustrating a relationship among a second group lens moving frame, a shutter block, a light shielding member, a straight guide ring, and a third group lens frame at a position along line B2-B2 in FIG. FIG. 14 is a cross-sectional view illustrating a relationship among a second group lens moving frame, a shutter block, a light shielding member, a rectilinear guide ring, and a third group lens frame at a position along the line A3-A3 in FIG. FIG. 14 is a cross-sectional view illustrating a relationship among a second group lens moving frame, a shutter block, a light shielding member, a rectilinear guide ring, and a third group lens frame at a position along line B3-B3 in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st group lens holding frame 2 2nd group lens holding frame 5 Shutter stopper member 5a Back guide pin 5b Backward movement control part 8 2nd group lens moving frame (lens holding member)
8a Cylindrical part 8b Straight guide groove (straight groove)
8c Inner flange portion 8d Group 2 retaining ring portion 8e Shutter block storage space 8f Front guide pin 8g Stopper mounting recess 8h Light shielding member support groove (straight groove)
8i Light shielding member support groove 8j Sub-control groove (straight groove)
8j-1 Rear end surface of sub-control groove (separation limiting portion)
10 Straight guide ring (straight guide member)
10a Rear end ring-shaped portion 10b Guide projection 10c Rotation guide claw 10d Straight guide key 10e Light shielding member control groove 10f Rear communication groove 10g Front opening 10h Position control projection (light shielding member movement restricting portion, first engagement portion)
10h-1 Standing wall surface 10i Movement restricting surface (second engaging portion)
11 Cam ring (Lens holding member driving means)
11a Gearing part 11b Guide protrusion 11c Rotation guide claw 12 Second delivery cylinder 13 First delivery cylinder 15 Light shielding member 16 Light shielding plate support frame 16a Annular part 16b First support key (radially opposed part)
16c 2nd support key 16d Front position control protrusion (2nd engaging part, radial direction protrusion)
16e Rear position control protrusion (light-shielding member movement restricting portion, first engaging portion, radial protrusion)
16e-1 Standing wall surface 16f Sub-control projection (separation limiting portion)
16f-1 Standing wall surface 17 Light-shielding plate 17a Light-shielding plate opening 22 Housing 23 Image sensor holder 23a Restriction protrusion 25 Low-pass filter 32 Fixing screw 27 Group biasing spring 51 Third lens group frame 70 Zoom lens barrel 71 Image sensor 100 Shutter block 100a Shutter holding frame 100b Front pin insertion hole 100c Rear pin insertion hole 100d Rear cover plate 100e First support key insertion recess 100f Second support key insertion recess 104 Barrier blade 150 Zoom motor 160 AF motor CF1 First group cam follower CF2 Second group Cam follower CG1 First group control cam groove CG2 Second group control cam groove LG1 First lens group LG2 Second lens group LG3 Third lens group O Optical axis S of photographing optical system Shutter blade

Claims (8)

A lens holding member for holding the lens group;
A rectilinear guide member that guides the lens holding member so as to be linearly movable in the optical axis direction;
Drive means for moving the lens holding member in the optical axis direction with respect to the rectilinear guide member;
A light shielding member supported so as to be movable in the optical axis direction along with the lens holding member; and a lens holding member provided between the linear guide member and the light shielding member, wherein the lens holding member is located at a predetermined position in the optical axis direction with respect to the linear guide member. A light-shielding member movement restricting unit that restricts the movement of the light-shielding member accompanying the lens holding member and changes the distance between the lens group in the optical axis direction when moving beyond the lens group:
A structure for supporting a light shielding member of a lens barrel, comprising: 2. The structure for supporting a light blocking member of a lens barrel according to claim 1, wherein the lens holding member has a linear groove in a direction parallel to the optical axis, and the rectilinear guide member moves relative to the linear groove in the optical axis direction. A guide key that can be fitted, and the light shielding member includes a radial facing portion that faces the guide key in a radial direction,
The light blocking member movement restricting portion is positioned side by side in a direction parallel to the optical axis on the opposing surfaces of the guide key of the linear guide member and the radial facing portion of the light blocking member, and is arranged in the optical axis direction of the linear guide member and the light blocking member. 1. A light shielding member support structure for a lens barrel comprising a first engaging portion engaged by relative movement. The light blocking member support structure for a lens barrel according to claim 2, further comprising a movement restricting direction by the first engaging portion on a facing surface of the guide key of the linear guide member and a radially facing portion of the light blocking member. Is a light shielding member support structure for a lens barrel in which a second engagement portion that determines an optical axis direction moving end of the light shielding member with respect to the linear guide member in the opposite direction is formed. 4. The light blocking member support structure for a lens barrel according to claim 3, wherein each of the first engagement portion and the second engagement portion is light in a groove formed on the facing surface of the guide key of the rectilinear guide member. A structure for supporting a light shielding member of a lens barrel, comprising an axial end face and a radial protrusion protruding from the opposing surface of the radially opposing portion of the light shielding member and positioned in the groove. 5. The lens barrel light shielding member support structure according to claim 1, wherein a separation is provided between the lens holding member and the light shielding member to determine a maximum separation position of the light shielding member and the lens group in the optical axis direction. A light shielding member supporting structure of a lens barrel provided with a limiting portion. 6. The lens barrel light blocking member supporting structure according to claim 5, wherein the separation limiting portion is provided on the optical axis end face of the linear groove in a direction parallel to the optical axis formed on the lens holding member, and on the light blocking member. A light-shielding member support structure for a lens barrel comprising radial protrusions that fit into the linear grooves. The lens barrel according to any one of claims 1 to 6, wherein the lens barrel is a zoom lens barrel, and the light shielding member is moved by the light shielding member movement restricting portion during the focal length changing operation between the wide end and the tele end. A light blocking member support structure for a lens barrel that is subject to movement restrictions. A lens holding member for holding the lens group;
A rectilinear guide member that guides the lens holding member so as to be linearly movable in the optical axis direction;
Drive means for moving the lens holding member in the optical axis direction with respect to the rectilinear guide member;
A light-shielding member supported so as to be movable in the optical axis direction along with the lens holding member; and a forward movement of the light-shielding member with respect to the linear guide member provided between the linear guide member and the light-shielding member. A first engaging portion for restricting and a second engaging portion for restricting rearward movement in the optical axis direction;
A structure for supporting a light shielding member of a lens barrel, comprising:

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