JP2010014959A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel capable of reliably protecting a biasing means which is swingable around an axis orthogonal to a plane parallel with an optical axis to bias an optical element-holding member without depending on the shape of a stationary barrel member. <P>SOLUTION: The lens barrel includes: the optical element-holding member for holding an optical element constituting a photographing optical system, which is moveable in an optical axis direction; the stationary barrel member surrounding the photographing optical system; the biasing means which is positioned on the outside of the stationary barrel member, is swingable around the axis orthogonal to the optical axis, and biases the optical element-holding member in the optical axis direction through a force applied portion extending in a radial direction from the center of swing; and a protective wall member which is provided as a separate member from the stationary barrel member, and fixed to the stationary barrel member to create an accommodation space for the biasing means between an outer surface of the stationary barrel member and the protective wall member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens barrel, and more particularly, to a protection structure for a biasing means for an optical element that advances and retreats in the optical axis direction.

In the lens barrel, the holding member of the optical element movable in the optical axis direction is responsible for a part of the drive mechanism, takes backlash in the drive mechanism, or stabilizes the position. For this purpose, an urging force in the optical axis direction is often applied. This type of urging means preferably has a smaller fluctuation range of the load per moving amount of the optical element from the viewpoint of reducing the load on the driving mechanism and improving the operation accuracy. It is possible to reduce the fluctuation range of. For example, when the biasing means is a tension spring or a compression spring, the load fluctuation range can be reduced by using a spring that is long in the expansion and contraction direction. However, a lens barrel that is required to be downsized has a problem that it is difficult to employ a tension spring or a compression spring that is long in the optical axis direction. In order to solve this problem, an urging means of a type that swings an urging portion (biasing portion) extending in the radial direction around an axis substantially orthogonal to a plane parallel to the optical axis of the optical system. Has been proposed (Patent Document 1). As a specific mode of the biasing means, a torsion spring or a combination of a swinging lever member and a biasing spring is assumed.
Japanese Patent Application No. 2007-291656

  The urging means of Patent Document 1 increases the effect of suppressing load fluctuations as the distance from the swinging center portion to the force application point on the optical element holding member increases, but on the other hand, increasing this distance increases the force application portion. Since there is a high possibility of interference with other members constituting the lens barrel, it is necessary to dispose the biasing member outside the central portion in the radial direction of the lens barrel where the movable members are concentrated.

  If the urging means is arranged on the outer diameter side of the lens barrel, it is desirable to protect it because the risk of deformation and error generation due to contact from the outside increases, but it may be difficult to configure the protection structure. In a lens barrel, generally, a fixed cylinder member that supports various movable members is provided on the outermost diameter side, and when this fixed cylinder member has a complete cylindrical shape without any interruption in the circumferential direction, It is difficult to form a protective part on the fixed cylinder member that further covers the urging means disposed on the outside. Specifically, when an attempt is made to manufacture a fixed cylindrical member having a projection that supports the biasing means on the outer surface side by resin molding, die cutting after molding is performed in the radial direction away from the optical axis. On the extension in the die-cutting direction, a wall portion shaped so as to cover the urging means could not be provided.

  The present invention has been made in view of the above problems, and an urging means for urging an optical element holding member by swinging about an axis substantially orthogonal to a plane parallel to the optical axis is provided as a fixed cylinder. It is an object of the present invention to provide a lens barrel that can be reliably protected without depending on the shape of a member.

  The lens barrel of the present invention is an optical element holding member that holds an optical element constituting a photographing optical system and is movable in the optical axis direction; a fixed cylindrical member that surrounds the photographing optical system; An urging means that oscillates about an axis substantially orthogonal to a plane parallel to the axis, and that urges the optical element holding member in the optical axis direction via an urging portion extending radially from the oscillating center; And a protective wall member that is a member separate from the fixed cylinder member and is attached to the fixed cylinder member and forms a storage space for the urging means between the fixed cylinder member and the outer surface.

  The protective wall member is preferably composed of an image sensor holding member that positions the image sensor at the imaging position of the photographing optical system.

  A swing support portion for supporting the swing center portion of the urging means may be provided on either the fixed cylinder member or the protective wall member.

  It is preferable that the protective wall member has a shape including a plane portion substantially parallel to the swing plane of the force applying portion of the urging member.

  As a specific example of the urging means, a torsion spring having a coil portion as a swinging central portion and an arm portion extending from the coil portion as an applied force portion can be applied.

  The present invention is particularly suitable for a lens barrel of a type in which the fixed cylinder member has a rotation member guide mechanism for controlling the position in the optical axis direction of the rotation member positioned inside thereof on the entire inner peripheral surface.

  According to the above lens barrel of the present invention, the urging means for urging the optical element holding member by oscillating about an axis substantially orthogonal to the plane parallel to the optical axis includes the fixed cylinder member, Since it is arrange | positioned between this fixed cylinder member and the protective wall member which consists of another member, an urging | biasing member can be reliably protected irrespective of the shape of a fixed cylinder member.

  A schematic structure of a zoom lens barrel 70 to which the present invention is applied will be described with reference to FIGS. 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 (rotating member) 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. 4) to the photographing state (FIG. 5). In the zoom range (between the wide end in the upper half of FIG. 5 and the tele end in the lower half of FIG. 5), it is rotated at a fixed position in the optical axis direction. More specifically, as shown in FIG. 12, the cam ring 11 is provided with a gearing portion 11a at the rear end portion in the optical axis direction, and a guide projection 11b is projected on the gearing portion 11a. The gearing portion 11 a meshes with the zoom gear 28 (FIGS. 6 and 7) rotated by the zoom motor 150, and the guide protrusion 11 b is a cam ring guide groove (rotating member guide mechanism) formed on the inner peripheral surface of the housing 22. ) Is slidably engaged with 22a. The cam ring guide groove 22a has a spiral groove portion 22a-1 at the rear in the optical axis direction and an annular groove portion 22a-2 with the photographing optical axis O at the front in the optical axis direction as the center. During the state (wide end), the guide protrusion 11b is guided by the spiral groove portion 22a-1 of the cam ring guide groove 22a, 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. In the zoom range from the wide end to the tele end, the guide protrusion 11b is guided by the annular groove portion 22a-2 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, It is rotated at a fixed position in the optical axis direction.

  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. The second lens group LG2 is held inside the second group lens moving frame 8 via the second group lens holding frame 2, and the shutter block 100 holding the shutter blades S is supported at the rear of the second lens group LG2. Yes. 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. 1, 2, and 4, the length of the optical system in the direction of the optical axis (from the object-side surface of the first lens group LG <b> 1 to the imaging element) is greater than that in the imaging state illustrated in FIGS. 3 and 5. 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 retracted state, first, the wide end extended state shown in the upper half section of FIG. 5 is obtained. When the zoom motor 150 is further driven in the lens barrel extending direction, the telephoto section shown in the lower half section of FIG. The end is extended. 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.

  Next, the position control mechanism of the third group lens frame (optical element holding member) 51 will be described. The housing 22 has a cam ring guide groove 22a on the inner peripheral surface, a cylindrical portion (fixed cylinder member) 22b centered on the photographing optical axis O, and an AF mechanism group positioned outside the rear end portion of the cylindrical portion 22b. Attached portion 22c and a front wall portion 22d positioned in front of the AF mechanism assembling portion 22c are provided. As shown in FIG. 6, the pinion 160 a provided on the rotation output shaft of the AF motor 160 protrudes to the rear surface side of the AF mechanism assembly portion 22 c of the housing 22. An intermediate gear 57 meshing with the pinion 160a and a driven gear 56 meshing with the intermediate gear 57 are pivotally supported on the rear surface side of the AF mechanism assembling portion 22c, and the rotation of the pinion 160a is via this gear train. Thus, it is transmitted to a screw shaft 58 that rotates integrally with the driven gear 56. The screw shaft 58 is supported between the housing 22 and the image sensor holder 23 so as to be rotatable about a rotation axis substantially parallel to the photographing optical axis O. A feed screw formed on the outer peripheral surface of the screw shaft 58 is screwed into an AF nut 54 that is guided in a straight line in the optical axis direction. By rotating the screw shaft 58 in the forward and reverse directions, the AF nut 54 is moved in the optical axis direction. Moved forward and backward.

  As shown in FIGS. 7 to 9, the third group lens frame 51 includes a pair of guide arm portions 51b in a substantially symmetric radial direction across the photographing optical axis O from a lens holding portion 51a that holds the third lens group LG3. , 51c are extended. A third group guide shaft 52 parallel to the photographing optical axis O is provided between the housing 22 and the image sensor holder 23, and the tip of one guide arm portion 51 b of the third group lens frame 51 with respect to the third group guide shaft 52. A guide hole 51d formed in the vicinity of the portion is slidably inserted and supported. The third group lens frame 51 is restricted in rotation by engaging a rotation restricting key 51e provided at the tip of the other guide arm 51c with the rotation restricting groove 22e on the inner peripheral surface of the housing 22. It is guided so that only a straight movement in the optical axis direction along the line 52 is possible.

  The third group lens frame 51 is biased forward in the optical axis direction by a torsion spring (biasing means) 55. As shown in FIGS. 7, 9 and 10, the torsion spring 55 includes a coil part (swinging center part) 55a, a support arm 55b protruding from the coil part 55a in the outer diameter direction, and an urging arm (energizing part). ) 55c, and the coil portion 55a is supported by a spring support protrusion 22f provided on the housing 22. The spring support protrusion 22f has an axial line on the outside of the cylindrical portion 22b of the housing 22 in a direction substantially orthogonal to the vertical plane P (FIG. 11) parallel to the imaging optical axis O (including the imaging optical axis O). It is the cylindrical protrusion formed toward. By fixing the spring retaining screw 39 to the screw hole formed at the center of the spring support protrusion 22f, the coil portion 55a of the torsion spring 55 is prevented from coming off from the cylindrical outer surface of the spring support protrusion 22f. Retained. The axis of the coil portion 55a in the holding state substantially coincides with the axis of the spring support protrusion 22f.

  A spring hooking protrusion 22g (FIG. 10) is provided on the outer surface of the cylindrical portion 22b of the housing 22 in the vicinity of the spring support protrusion 22f. The support arm 55b of the torsion spring 55 is hooked on the spring hooking protrusion 22g. It has been. On the other hand, the urging arm 55 c is hooked on a spring hooking protrusion 51 f provided in the vicinity of the guide hole 51 d of the third group lens frame 51. The urging arm 55c swings about a swing center axis 55x that is substantially coincident with the axis of the coil portion 55a (that is, substantially perpendicular to the vertical plane P parallel to the photographing optical axis O) as a center (fulcrum). In a free state in which the swinging force applying portion is not hung on the spring hooking protrusion 51f, the swinging force portion faces the direction indicated by "55c (F)" in FIG. Then, from this free state, the urging arm 55c is rotated approximately half counterclockwise in FIG. 10, and the vicinity of the tip of the urging arm 55c is applied to the rear surface in the optical axis direction of the spring hooking projection 51f. As a result, the amount of bending (twisting) of the torsion spring 55 increases, and the force in the direction of bending cancellation acts as a load for the urging arm 55c to press the spring hooking protrusion 51f forward in the optical axis direction. That is, it is in an applied force state in which an urging force forward in the optical axis direction is applied to the third group lens frame 51 via the urging arm 55c.

  The third group lens frame 51 thus provided with a biasing force forward in the optical axis direction by the torsion spring 55 is a nut provided in the vicinity of the guide hole 51d (that is, positioned in the vicinity of the distal end portion of the guide arm portion 51b). When the contact portion 51g contacts the AF nut 54, the forward movement is restricted. That is, the third group lens frame 51 is held in a state where the nut abutting portion 51g is in contact with the AF nut 54 by the urging force of the torsion spring 55, and the front and rear positions of the third group lens frame 51 in the optical axis direction are the AF nuts. Depends on 54. As described above, the AF nut 54 is moved forward and backward in the optical axis direction by the screw shaft 58 by rotating the pinion 160a of the AF motor 160 forward and backward, and as a result, the optical axis of the third group lens frame 51 is moved. The direction position is controlled according to the driving direction and driving amount of the AF motor 160. For example, when the AF nut 54 is moved forward by the AF motor 160, the third group lens frame 51 is moved forward by the urging force of the torsion spring 55 by the amount of movement of the AF nut 54. On the contrary, when the AF nut 54 is moved backward from the forward movement position, the AF nut 54 pushes the nut abutting portion 51g, and the third lens group frame 51 moves backward against the urging force of the torsion spring 55. Is done.

  The housing 22 is provided with an origin position detection sensor 40 that detects the rearward movement end of the third group lens frame 51 in the optical axis direction by the AF motor 160. The origin position detection sensor 40 is formed of a transmissive photo interrupter, and the state where the sensor passage plate 51h of the third group lens frame 51 is positioned between the bifurcated light projecting unit and the light receiving unit is located behind the third group lens frame 51. Detected as moving end. The AF motor 160 is a stepping motor, and the amount of movement of the third lens group LG3 during focusing is calculated as the number of driving steps of the AF motor 160 with the rearward movement end as the origin position. A solid line in FIG. 10 shows the rear moving end of the third group lens frame 51 in the movable range controlled by the AF motor 160, and a two-dot chain line in FIG. 10 shows in the movable range. This is the front moving end of the third group lens frame 51.

  According to the biasing structure by the torsion spring 55 described above, the swing angle of the biasing arm 55c when the third lens group frame 51 is moved between the front and rear moving ends by the AF motor 160 (the amount of deflection of the torsion spring 55). Is much smaller than the swing angle (the amount of deflection of the torsion spring 55) of the urging arm 55c when the biasing arm 55c is brought into an applied state in which it is engaged from the free state. Therefore, the fluctuation of the load of the torsion spring 55 in the movable range of the third group lens frame 51 by the AF motor 160 is small, and the energy required for driving the third group lens frame 51 is averaged at a low level. The burden can be reduced. Further, since the load fluctuation according to the movement of the third group lens frame 51 is small, it can be driven smoothly over the entire movement range, and abnormal noise from the gear train that transmits the driving force from the AF motor 160 is also generated. It is hard to occur.

  As a factor that suppresses the load fluctuation in the torsion spring 55, the urging arm from the coil portion 55a that is the fulcrum of swing to the spring hooking projection 51f that is the point of application (action point) to the third group lens frame 51 The length of 55c is also relevant. The biasing arm 55c per unit movement amount of the third group lens frame 51 becomes larger as the distance from the swinging central axis 55x to the force applied point to the spring hooking protrusion 51f, that is, the rotation radius of swinging near the tip of the biasing arm 55c increases. The displacement angle becomes smaller, and the fluctuation of the spring load can be suppressed. Then, by positioning the torsion spring 55 outside the cylindrical portion 22b of the housing 22, the biasing arm 55c has such a length without interfering with other members in the cylindrical portion 22b. It is possible.

  Although the above effect can be obtained by positioning the torsion spring 55 outside the cylindrical portion 22b of the housing 22, the torsion spring 55 is not protected by the housing 22 as shown in FIG. . As shown in FIG. 12, the cylindrical portion 22b of the housing 22 has three cam ring guide grooves 22a provided on the inner peripheral surface thereof, and is formed in the circumferential direction because it is formed over substantially the entire area in the circumferential direction. It must be a complete cylinder with no interruptions along the way. Although the housing 22 is formed as a molded product of synthetic resin, it is difficult to manufacture a double wall structure having a wall portion that covers the torsion spring 55 outside the cylindrical portion 22b that is a complete cylindrical body.

  In the zoom lens barrel 70 of the present embodiment, the image sensor holder 23 attached to the rear portion of the housing 22 is provided with a protective wall portion (protective wall member) 23 a that covers the outside of the torsion spring 55. As shown in FIGS. 2, 7, 8, and 11, the protective wall portion 23 a includes a planar side wall portion (planar portion) 23 b that is substantially parallel to the swinging plane of the urging arm 55 c of the torsion spring 55, A box-like portion 23c surrounding the lower coil portion 55a is provided, and a front edge portion in the optical axis direction extending from the side wall portion 23b to the box-like portion 23c abuts on the front wall portion 22d of the housing 22 to form a box-like shape. A side edge portion of the portion 23 c comes into contact with a lower support portion 22 h provided in the housing 22. Step portions 22d-1 and 22h-1 for fitting and supporting the contact edge on the protective wall portion 23a side are formed on the front wall portion 22d and the lower support portion 22h, respectively. As shown in FIG. 8, an optical axis direction groove 23d is formed on the inner side surface of the side wall portion 23b of the protective wall portion 23a to prevent interference with the spring hooking projection 51f when the third group lens frame 51 is moved. A sensor storage portion 23e for storing the origin position detection sensor 40 is formed at the rear portion of the groove 23d.

  When the image sensor holder 23 is assembled to the housing 22, the side edge of the box-shaped portion 23c in the protective wall 23a is slid forward while being supported on the step portion 22h-1 of the lower support portion 22h. When the main body portion 23 abuts on the rear surface portion of the housing 22, the front edge portion of the protective wall portion 23a is also brought into contact with the front wall portion 22d and fitted into the stepped portion 22d-1. Then, by screwing and fixing the image pickup device holder 23 to the housing 22, the protection wall 23 a is in a protected state in which the outside of the torsion spring 55 is completely closed as shown in FIG. 2. In this protected state, as shown in FIG. 11, the torsion spring 55 is held in the storage space Q between the outer peripheral surface of the cylindrical portion 22 b of the housing 22 and the protective wall portion 23 a of the image sensor holder 23. The torsion spring 55 is protected from contact with the movable member inside the zoom lens barrel 70 by the cylindrical portion 22b, and contact from the outside of the zoom lens barrel 70 is also protected by the protective wall portion 23a. Therefore, there is no possibility that the torsion spring 55, particularly the urging arm 55c, may be irreversibly deformed different from the elastic deformation in the normal use state due to contact with another member or the like, and the zoom lens barrel 70 In the assembled state, the accuracy of position control of the third group lens frame 51 is not impaired.

  As described above, since the image sensor holder 23 fixed to the housing 22 is provided with the protective wall portion 23a that covers the outside of the torsion spring 55 in a state of being attached to the housing 22, the torsion spring positioned outside the housing 22 is provided. 55 can be protected. In particular, as in the present embodiment, in the resin molding, it is difficult to form a wall portion that covers the torsion spring 55 outside the cylindrical portion 22b in the housing 22 where the cylindrical portion 22b forms a complete cylindrical shape. Even in the structure, the torsion spring 55 can be reliably protected without depending on the shape of the housing 22. In the housing 22, the front wall portion 22d and the lower support portion 22h with which the protective wall portion 23a abuts are both plate-like portions protruding from the outer peripheral surface of the cylindrical portion 22b, and the spring support protrusion 22f. Unlike the protective wall portion 23a, it can be formed as a part of the housing 22 because it can be formed by punching in the same direction as the first embodiment.

  In the above embodiment, the cam ring 11 is moved in the optical axis direction by the spiral groove portion 22a-1 of the cam ring guide groove 22a formed on the inner peripheral surface of the cylindrical portion 22b of the housing 22. Instead, a payout structure using a helicoid as shown in FIG. 13 may be used. The cylindrical portion 22b 'of the housing 22' shown in FIG. 13 has a cam ring guide groove (rotating member guide mechanism) 22a 'composed of a spiral groove portion 22a-1' and an annular groove portion 22a-2 'on the inner peripheral surface. The guide projection 11b 'provided on the gear ring portion 11a' of the cam ring 11 'is fitted into the cam ring guide groove 22a'. Unlike the previous embodiment, the guide of the cam ring 11 'in the optical axis direction is not the relationship between the spiral groove portion 22a-1' of the cam ring guide groove 22a 'and the guide protrusion 11b', but the cylindrical portion 22b. The inner surface helicoid (rotating member guide mechanism) 22z formed on the inner peripheral surface of ′ and the outer surface helicoid (rotating member guide mechanism) 11z formed on the gearing portion 11a ′ of the cam ring 11 ′. Then, when the cam ring 11 'is extended forward in the optical axis direction by the helicoids 11z and 22z, the helicoid screwing is released and the guide projection 11b' enters the annular groove portion 22a-2 'of the cam ring guide groove 22a'. The cam ring 11 ′ is in a fixed position rotation state that is not moved in the optical axis direction. Also in this embodiment, since the cylindrical portion 22b 'of the housing 22' is a complete cylindrical body without a discontinuous portion in the circumferential direction in order to control the movement of the cam ring 11 ', the same as in the previous embodiment. The spring protection structure is effective.

  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, the optical element that is moved and urged in the optical axis direction is the third lens group LG3 that functions as a focusing lens group, but in the present invention, the optical element that is moved and urged by the urging means is Other than such a lens group may be used.

  The urging means of the embodiment is the torsion spring 55, but the urging force portion corresponding to the urging arm 55c of the torsion spring 55 is an independent lever member, and the urging force is applied to this lever member by another spring member. The present invention can also be applied to a lens barrel provided with a biasing means of the type to be applied.

  The torsion spring 55 according to the embodiment gives a biasing force forward in the optical axis direction. However, in the present invention, the biasing direction by the biasing means is not limited to this, and the biasing force toward the rear in the optical axis direction is not limited thereto. It may be a force means.

  In the embodiment, the spring support protrusion 22 f that supports the coil portion 55 a of the torsion spring 55 is provided on the cylindrical portion 22 b side of the housing 22, but similar to the protective wall portion 23 a side of the image sensor holder 23. Support protrusions can also be provided.

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 the external appearance perspective view which looked at the accommodation state of the zoom lens barrel from back. 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 of the imaging state of the zoom lens barrel. It is a rear perspective view of the zoom lens barrel with the image sensor holder removed. It is a back perspective view of the state where the position control mechanism of the 3 group lens frame was disassembled. It is a front perspective view of the state which decomposed | disassembled the position control mechanism of a 3 group lens frame. It is a back perspective view which shows the principal part of a 3 group lens frame and its position control mechanism. It is a side view which shows the effect | action of the torsion spring which urges | biases a 3 group lens frame. It is a rear view of the principal part of a zoom lens barrel showing the protective housing structure of a torsion spring that biases the third group lens frame. It is a development top view of the cylindrical part of a housing, and a cam ring. It is an expansion | deployment top view which shows embodiment from which the cylindrical part of a housing differs from a cam ring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st group lens holding frame 2 2nd group lens holding frame 8 2nd group lens moving frame 10 Straight guide ring 11 11 'Cam ring (rotating member)
11a 11a 'gearing part 11b 11b' guide projection 11z outer surface helicoid (rotating member guide mechanism)
12 Second feeding cylinder 13 First feeding cylinder 22 22 'Housing 22a 22a' Cam ring guide groove (rotating member guide mechanism)
22a-1 22a-1 'Spiral groove part 22a-2 22a-2' Annular groove part 22b Cylindrical part (fixed cylinder member)
22c AF mechanism assembly part 22d Front wall part 22d-1 Step part 22e Rotation restricting groove 22f Spring support protrusion 22g Spring hooking protrusion 22h Lower support part 22h-1 Step part 22z Inner surface helicoid (rotating member guide mechanism)
23 Image sensor holder 23a Protective wall part (protective wall member)
23b Side wall (plane part)
23c Box-shaped portion 23d Optical axis direction groove 23e Sensor housing portion 25 Low pass filter 27 Group bias spring 28 Zoom gear 39 Spring retaining screw 40 Origin position detection sensor 51 Third group lens frame (optical element holding member)
51a Lens holding portion 51b 51c Guide arm portion 51d Guide hole 51e Rotation restriction key 51f Spring hooking projection 51g Nut abutting portion 51h Sensor passage plate 52 Third group guide shaft 54 AF nut 55 Torsion spring (biasing means)
55a Coil (swinging center)
55b Support arm 55c Energizing arm (forced portion)
55x Oscillation center shaft 56 Driven gear 57 Intermediate gear 58 Screw shaft 70 Zoom lens barrel 71 Image sensor 100 Shutter block 104 Barrier blade 150 Zoom motor 160 AF motor 160a Pinion 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 P of photographing optical system Vertical plane S parallel to photographing optical axis Shutter blades Q Cylindrical portion of housing Storage space between the protective walls of the image sensor holder

Claims (6)

An optical element holding member that holds an optical element constituting the photographing optical system and is movable in the optical axis direction;
A fixed cylinder member surrounding the imaging optical system;
The optical element holding member is located on the outer side of the fixed cylinder member and is swingable about an axis substantially orthogonal to a plane parallel to the optical axis, and via an attachment portion extending in the radial direction from the swing center portion. An urging means for urging the urging means in the direction of the optical axis; and a member separate from the fixed cylinder member, and is attached to the fixed cylinder member to form a storage space for the urging means between the fixed cylinder member and the outer surface. Protective wall member;
A lens barrel characterized by comprising: 2. The lens barrel according to claim 1, wherein the protective wall member is an imaging element holding member that positions the imaging element at an imaging position of the photographing optical system. 3. The lens barrel according to claim 1, wherein either one of the fixed barrel member and the protective wall member is provided with a swing support portion that supports a swing center portion of the biasing means. . 4. The lens barrel according to claim 1, wherein the protective wall member includes a plane portion that is substantially parallel to a swing plane of the force-applying portion of the biasing member. 5. 5. The lens barrel according to claim 1, wherein the urging means includes a coil portion that is the swinging central portion and an arm portion that extends in a radial direction from the coil portion. A lens barrel that is a spring. 6. The lens barrel according to claim 1, wherein the fixed cylinder member has a rotation member guide mechanism for controlling an optical axis direction position of a rotation member positioned on an inner side of the entire inner peripheral surface. Lens barrel.

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