JP5905290B2 - Retractable lens barrel - Google Patents

Description

  The present invention relates to a retractable lens barrel.

The retractable lens barrel disclosed in Patent Literature 1 is located in front of the first group moving cylinder, the front end lens (first lens group) supported by the first group moving cylinder, and the light. A barrier support member having a barrier opening located on the shaft, a barrier blade supported by the barrier support member for opening and closing the barrier opening, a lens cam groove engaged with a lens side cam follower fixed to the lens support frame, and A cam ring that has a barrier cam groove engaged with a barrier side cam follower that moves together with the barrier support member, and rotates the lens support frame and the barrier support member in the optical axis direction by rotating around the optical axis; It has. The front end lens constitutes a photographic optical system together with other lens groups, and each lens group constituting the photographic optical system is placed on the optical axis in the order of the storage position, the wide end position, and the tele end position by the rotational force of the cam ring. Gradually move forward along. The barrier support member also gradually moves forward along the optical axis in the order of the storage position, the wide end position, and the tele end position by the rotational force of the cam ring. The barrier blade closes the barrier opening when the photographing optical system is located at the storage position, and opens the barrier opening when the photographing optical system is located in the photographing region (between the wide end position and the tele end position).
Generally, if the lens cam groove and the barrier cam groove have different shapes (if the movement trajectories of the front end lens and the barrier support member are different), it becomes difficult to manufacture the cam ring. Therefore, in Patent Document 1, the lens cam groove and the barrier cam groove have the same shape in order to facilitate the manufacture of the retractable lens barrel (the movement trajectories of the front end lens and the barrier support member are matched). ).

However, like the retractable lens barrel disclosed in Patent Document 2, the front-rear distance between the barrier support member and the front end lens at the wide end position is shorter than the front-rear distance between the barrier support member and the front end lens at the tele end position. The following advantages can be obtained by changing the shape of the lens cam groove and the barrier cam groove.
That is, when the photographic optical system is positioned at the wide end position, the front end lens approaches the barrier support member, so that the effective light beam that is incident on the front end lens even though the angle of view of the front end lens is large. Is not vignetted by the barrier support member (barrier opening). On the other hand, when the photographic optical system is located at the tele end position, the front end lens is largely separated rearward from the barrier support member, so that a large hood effect can be obtained by the barrier support member (harmful rays to the front end lens). Intrusion can be prevented), and since the angle of view of the front end lens is reduced, the effective light beam incident on the front end lens is not vignetted by the barrier support member (barrier opening).

JP 2004-258646 A JP-A-8-146296

In order to obtain a large hood effect when the photographic optical system is located at the telephoto end position, a large difference is provided between the optical axis direction length of the lens cam groove and the optical axis direction of the barrier cam groove. What is necessary is just to make the front-back space | interval of the barrier support member and front end lens in an end position as large as possible.
However, if there is a large difference between the optical axis length of the lens cam groove and the optical axis direction of the barrier cam groove, a useless space in which no cam groove is formed on the cam ring is formed (cam The ring cannot be used effectively (refer to S in FIG. 7).
For this reason, if the front-rear distance between the barrier support member and the front end lens at the tele end position is increased, the front end position of the barrier cam groove is greatly shifted forward from the front end position of the lens cam groove (see FIG. 7). The ring becomes unnecessarily long, and as a result, the thickness of the retractable lens barrel (and the entire camera) in the retracted state becomes unnecessarily large.

  The present invention utilizes a cam groove formed in a cam ring and a cam follower that moves together with the front end lens and the barrier support member, and when the photographic optical system is positioned at the wide end position, the front end lens is mounted on the barrier support member. When the optical system is close and the telephoto end is located at the tele end position, the front end lens is greatly separated backward from the barrier support member, but the optical axis dimension of the cam ring can be minimized. An object of the present invention is to provide a retractable lens barrel.

  The retractable lens barrel of the present invention includes a photographing optical system in which the front end lens gradually moves forward along the optical axis in the order of the storage position, the wide end position, and the tele end position, and a lens support frame that supports the front end lens. A barrier support member having a barrier opening positioned on the optical axis, the position of the optical axis direction being changed according to the position of the front end lens while being positioned immediately before the front end lens, and the photographing optical system A barrier blade supported by the barrier support member that closes the barrier opening when positioned at the storage position and opens the barrier opening when the imaging optical system is positioned between the wide end position and the tele end position. A lens cam groove that engages with a lens side cam follower that moves together with the lens support frame, and a barrier cam that engages a barrier side cam follower that moves together with the barrier support member And a cam ring that advances and retracts the lens support frame and the barrier support member in the optical axis direction by rotating around the optical axis, and the photographing optical system is located at the storage position. The optical axis direction distance between the front surface of the barrier support member and the front end lens is LA, and the optical axis direction distance between the front surface of the barrier support member and the front end lens when the photographing optical system is located at the wide end position. LB, where the distance in the optical axis direction between the front surface of the barrier support member and the front end lens when the photographing optical system is located at the tele end position is LC, the relationship LA = LC> LB is established. It is characterized by that.

  When the front end lens is located at the storage position, the lens cam groove portion to which the lens side cam follower engages is Pa1, and the barrier cam groove portion to which the barrier side cam follower engages is Pa2. When the front end lens is positioned at the telephoto end position, the lens cam groove portion engaged with the lens side cam follower is Pc1, and the barrier cam groove portion engaged with the barrier side cam follower is Pc2. Then, the separation distance in one direction along the optical axis of Pa2 viewed from Pa1 and the separation distance in one direction of Pc2 viewed from Pc1 may be the same.

  The cam ring is an annular member centered on the optical axis, a part of Pa1 and a part of Pa2 are arranged in the circumferential direction of the cam ring, and a part of Pc1 and a part of Pc2 May be arranged in the circumferential direction.

The retractable lens barrel of the present invention has a distance LB between the front surface of the barrier support member and the front lens when the photographing optical system is located at the wide end position, and an optical distance when the photographing optical system is located at the tele end position. When the distance in the optical axis direction between the front surface of the barrier support member and the front end lens is LC,
LC> LB
The relationship is established.
That is, when the photographic optical system is positioned at the wide end position, the front end lens approaches the barrier support member, so that the effective light beam that is incident on the front end lens even though the angle of view of the front end lens is large. Is not vignetted by the barrier support member (barrier opening). On the other hand, when the photographic optical system is located at the tele end position, the front end lens is largely separated rearward from the barrier support member, so that a large hood effect can be obtained by the barrier support member (front lens for harmful rays). In addition, since the angle of view of the front end lens is small, the effective luminous flux incident on the front end lens is not vignetted by the barrier support member (barrier opening).

Furthermore, when the optical axis direction distance between the front surface of the barrier support member and the front end lens when the photographing optical system is located at the storage position is LA,
LA = LC
The relationship is established.
That is, since the front-rear distance between the barrier support member and the front end lens at the tele end position is the same as the front-rear distance between the barrier support member and the front end lens at the storage position, the front-rear distance between the barrier support member and the front end lens at the tele end position is It does not become extremely large. Therefore, the difference between the optical axis length of the lens cam groove and the optical axis direction of the barrier cam groove is small, and it is difficult to form a useless space where the cam groove is not formed on the cam ring (use the cam ring effectively). be able to).
Further, since the front end position of the barrier cam groove is not larger than the front end position of the lens cam groove, the optical axis direction of the cam ring and the retractable lens barrel (and the entire camera) in the stored state It is possible to make the dimensions as small as possible.

It is a longitudinal cross-sectional view of the storage (collapse) state of the zoom lens barrel of one embodiment to which the present invention is applied. It is an upper half longitudinal cross-sectional view of the zoom lens barrel in a wide-end shooting state. It is an upper half longitudinal cross-sectional view of the zoom lens barrel in a tele end shooting state. It is a disassembled perspective view of the zoom lens barrel. It is an expanded view showing the outer peripheral surface of a cam ring. It is a figure showing the front-back space | interval of the front surface of a decoration ring (lens barrier mechanism) and the front surface of a 1st lens group when an imaging optical system is located in each position of a storage position, a wide end position, and a tele end position. It is an expanded view of the cam ring of a prior art example.

  First, main components of the zoom lens barrel 10 to which the present invention is applied will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view in the storage state, FIG. 2 is an upper half longitudinal sectional view at the wide end, FIG. 3 is an upper half longitudinal sectional view at the tele end, and FIG. 4 is an exploded perspective view. As shown in FIGS. 2 and 3, the photographing optical system of the zoom lens barrel 10 at the time of photographing has a first lens group L1 (front end lens), a second lens group L2, a shutter 34 (aperture), in order from the object side. A third lens group (retractable optical element) L3, a fourth lens group L4, an infrared cut filter 11 and a CMOS sensor (solid-state imaging device) 12 are included. The optical axis of this photographing optical system is indicated by Z1. Zooming is performed by advancing and retracting the first lens unit L1, the second lens unit L2, and the third lens unit L3 along a predetermined locus in the direction of the photographing optical axis Z1, and focusing is performed by moving the fourth lens unit L4 in the same direction. To do. “Front” and “rear” mean the subject side and the imaging surface side, respectively.

  The zoom lens barrel 10 is mounted in a camera body (not shown), and includes a fixed ring 13 fixed to the camera body and an image sensor holder 14 fixed to the rear portion of the fixed ring 13. A CMOS sensor 12 is fixed at the center of the image sensor holder 14, and an infrared cut filter 11 is held at the front of the CMOS sensor 12.

  An AF lens frame (fourth group frame) 17 that holds the fourth lens unit L4 is supported in the fixed ring 13 so as to be linearly movable in the optical axis Z1 direction. The AF lens frame 17 is guided between a fixed ring 13 and a CCD holder 14 by a pair of AF guide shafts 18 that are fixed in parallel to the photographing optical axis Z1. A guide hole (guide groove) formed in 17 is slidably fitted.

  The AF lens frame 17 is advanced and retracted in the direction of the optical axis Z <b> 1 by the driving force of the AF motor 19. An AF nut 20 is screwed into a feed screw formed on the drive shaft of the AF motor 19. The AF lens frame 17 is slidably engaged with the AF nut 20 in the direction of the optical axis Z1, and is urged forward by the AF frame urging spring 21, and is applied to the AF nut 20 by this urging force. By attaching, the forward moving end of the AF lens frame 17 is determined. When the AF nut 20 moves rearward in the optical axis Z1 direction, the AF lens frame 17 is pressed by the AF nut 20 and moved rearward. With the above structure, when the drive shaft of the AF motor 19 is rotated forward and backward, the AF lens frame 17 is advanced and retracted in the optical axis direction.

  A zoom gear (long pinion) 22 having an axis parallel to the photographing optical axis Z1 is rotatably supported on the fixed ring 13. The zoom gear 22 is positioned so as to be exposed on the inner peripheral surface side of the fixed ring 13, and is rotated forward and backward by a zoom motor 23 and a gear train 24.

  A female helicoid 13a and a rectilinear guide groove 13b parallel to the optical axis are formed on the inner peripheral surface of the fixed ring 13. A male helicoid 25a of a helicoid ring (first advancing / retracting cylinder) 25 is screwed into the female helicoid 13a of the fixed ring 13, and a rectilinear guide ring 26 located on the inner circumference of the helicoid ring 25 is inserted into the rectilinear guide groove 13b. The radial protrusions 26a are engaged. The helicoid ring 25 and the rectilinear guide ring 26 are coupled so as to move together in the direction of the optical axis Z1 so that relative rotation is freely possible. That is, the guide protrusions 26 b formed on the outer peripheral surface of the rectilinear guide ring 26 are engaged with the circumferential guide grooves 25 b (FIG. 5) formed on the inner peripheral surface of the helicoid ring 25.

  A gear that meshes with the zoom gear 22 described above is formed on a part of the outer periphery of the helicoid ring 25, and a rotation transmission groove 25c (FIG. 5) parallel to the optical axis Z1 is formed on the inner peripheral surface of the helicoid ring 25. Has been. A cam ring 27, which is an annular member centered on the photographing optical axis Z <b> 1, fitted on the inner periphery of the linear guide ring 26 is provided with a follower 27 a that projects in the radial direction. After passing through the cam groove 26 c, it fits in the rotation transmission groove 25 c of the helicoid ring 25. That is, when the helicoid ring 25 rotates through the zoom gear 22, the rotation is transmitted to the cam ring 27 through the follower 27a. The position of the cam ring 27 in the optical axis Z1 direction is determined by the position of the linear guide ring 26 in the optical axis Z1 direction and the shape of the cam groove 26c.

A first group frame 28 (lens support frame) that supports the first lens unit L1 is positioned on the outer peripheral side of the cam ring 27, and a lens barrier mechanism 29 is supported on the front end portion on the outer peripheral side of the first group frame 28. The barrier support cylinder (third advance / retreat cylinder) 30 is positioned. Three cam followers 28a (lens-side cam followers) are fixed to the vicinity of the rear end of the inner peripheral surface of the first group frame 28 at equal angular intervals in the circumferential direction, and in the vicinity of the rear end of the inner peripheral surface of the barrier support cylinder 30 Three cam followers 30a (barrier side cam followers) are fixed to the portion at equal angular intervals in the circumferential direction.
On the outer peripheral surface of the cam ring 27, three lens cam grooves 27b1 with which the cam followers 28a are respectively engaged and three barrier cam grooves 27b2 with which the cam followers 30a are respectively engaged are equiangularly spaced in the circumferential direction. An inner surface cam groove 27c with which the cam follower of the second group frame 31 supporting the second lens group L2 is engaged is formed on the inner peripheral surface.
The lens barrier mechanism 29 positioned in front of the first group frame 28 includes a barrier frame 29a (barrier support member) having a rectangular barrier opening provided at the front end of the barrier support cylinder 30, and a barrier so as to open and close the barrier opening. A pair of inner barrier blades 29b and a pair of outer barrier blades 29c supported on the base frame 29a, a pair of torsion springs 29d for urging the barrier blades 29b and 29c in the direction of closing the barrier opening, and the barrier base frame 29a A barrier presser plate 29e (barrier support member) having a barrier opening which is larger than the barrier opening and capable of rotating relative to the barrier base frame 29a, and the barrier base frame 29a. A decoration ring 29f (barrier support member) fixed to the front surface and a biasing spring 29g for rotating and biasing the barrier pressing plate 29e are provided. The upper inner barrier blade 29b and the outer barrier blade 29c, and the lower inner barrier blade 29b and the outer barrier blade 29c are coaxially rotatable by a pair of common shafts (not shown) provided on the barrier frame 29a. The upper and lower inner barrier blades 29b are urged to rotate in the closing direction (direction for closing the barrier opening) by the torsion spring 29d. The upper inner barrier blade 29b and the outer barrier blade 29c, and the lower inner barrier blade 29b and the outer barrier blade 29c are both interlocked in both the opening and closing directions. The barrier pressing plate 29e is linked to the upper and lower inner barrier blades 29b, and resists the biasing force of the torsion spring 29d from the initial position that allows the inner barrier blades 29b to be positioned at the fully closed position. Thus, it can be rotated between the operating position moved to the fully open position and is urged to rotate toward the operating position by the urging spring 29g. Further, the front surface of the decorative ring 29f is always positioned in front of the front surface of the first lens unit L1.

On the other hand, on the outer periphery of the cam ring 27, the second advance / retreat cylinder 32 guided by the rectilinear guide ring 26 is positioned. The second advancing / retracting cylinder 32 and the cam ring 27 are coupled so as to freely rotate relative to each other and move together in the optical axis direction. Further, the first group frame 28, the barrier support cylinder 30 and the second group frame 31 are directly or indirectly guided to the second advance / retreat cylinder 32, and the first group frame 28, the barrier support cylinder 30 are rotated by the rotation of the cam ring 27. The second group frame 31 advances and retreats in the optical axis direction. That is, when the cam ring 27 rotates forward, the first group frame 28, the barrier support cylinder 30 and the second group frame 31 are at the storage position (FIG. 1), the wide end position (FIG. 2), and the tele end position (FIG. 3). The first group frame 28, the barrier support cylinder 30 and the second group frame 31 are moved to the front end position, the wide end position, and the storage position by gradually moving forward along the photographing optical axis Z1 in order and the cam ring 27 reversely rotating. And gradually move backward along the photographing optical axis Z1.
When the zoom lens barrel 10 (the first group frame 28, the barrier support cylinder 30) is located at the storage position, the barrier engaging portion formed at the front end of the cam ring 27 rotates the biasing spring 29g with the biasing spring 29g. Since it is moved to the initial position against the force, the upper and lower inner barrier blades 29b and the outer barrier blade 29c are positioned at the fully closed position for closing the barrier opening by the biasing force of the torsion spring 29d. When the cam ring 27 is rotated forward as the zoom lens barrel 10 (the first group frame 28, the barrier support cylinder 30) moves from the storage position to the wide end position side, the barrier engaging portion of the cam ring 27 becomes the barrier. Since the presser plate 29e is separated from the presser plate 29e, the barrier presser plate 29e is rotated to the operating position by the rotation biasing force of the biasing spring 29g. Then, the upper and lower inner barrier blades 29b and the outer barrier blades 29c move to the fully open position against the biasing force of the torsion spring 29d, so that the zoom lens barrel 10 (the first group frame 28, the barrier support tube 30) is in the wide end position. And the telephoto end position (including the wide end position and the telephoto end position), the barrier opening is opened. Further, when the cam ring 27 reverses as the zoom lens barrel 10 (the first group frame 28, the barrier support cylinder 30) returns from the photographing region to the storage position, the barrier engaging portion biases the barrier pressing plate 29e. Since the spring 29g is moved to the initial position against the rotational biasing force of the spring 29g, the upper and lower inner barrier blades 29b and the outer barrier blade 29c are returned to the fully closed position by the biasing force of the torsion spring 29d.

  Further, on the inner periphery of the cam ring 27, a third group support ring 33 that supports the third lens group L3 is located. The third group support ring 33 is coupled to the cam ring 27 so as to move together in the optical axis direction so as to be freely rotatable relative to the cam ring 27, and is guided linearly to the second group frame 31.

  A shutter 34 and a spring receiving annular plate 35 are fixed in front of the third group support ring 33, and sandwiched between a pair of intergroup springs (compression coil springs) 36 and 37 in front of the spring receiving annular plate 35. An axially moving throttle ring 38 is located. The axially moving throttle ring 38 is guided linearly by the third group ring 33, and the front end portion of the front intergroup spring 36 is supported (abutted) on the second group frame 31.

  On the rear side (rear surface) of the third group support ring 33, an anti-vibration base 40 that is driven in a plane orthogonal to the optical axis in a direction that cancels camera shake applied to the camera is supported. The third group frame 42 that supports the third lens group L3 is supported so as to be swingable about an axis 41 outside the optical axis parallel to the optical axis Z1 on the vibration isolation base 40. Reference numeral 43 denotes an anti-vibration cover that supports the anti-vibration base 40 between the third group support ring 33. The third group frame 42 holds the third lens group L3 on the optical axis Z1 in the shooting state of FIGS. 2 and 3, and is moved to the storage position away from the optical axis Z1 in the storage state of FIG. The details of these anti-vibration mechanisms and lens group insertion / removal mechanisms are well known, and are not related to the gist of the present invention, so that the description of specific configurations is omitted.

Next, features of the present invention (cam ring 27, first group frame 28, lens barrier mechanism 29, and barrier support cylinder 30) will be described in detail.
The cam follower 28a and the cam follower 30a have a conical shape in which a tip end (inner peripheral side end) is cut by a plane, and the cam follower 30a has a larger diameter than the cam follower 28a.
Specific shapes of the lens cam groove 27b1 and the barrier cam groove 27b2 of the cam ring 27 are as shown in FIG. The cross-sectional shapes of the lens cam groove 27b1 and the barrier cam groove 27b2 are substantially the same as the cross-sectional shapes of the cam follower 28a and the cam follower 30a (see FIGS. 2 and 3), and the barrier cam groove 27b2 is the lens cam groove. It is wider than 27b1. The overall shape (deployed shape) of the lens cam groove 27b1 and the barrier cam groove 27b2 is substantially the same. In other words, in the vicinity of the rear end of the lens cam groove 27b1 and the barrier cam groove 27b2, the photographing optical system including the first lens group L1, the second lens group L2, the third lens group L3, and the fourth lens group L4. A storage engagement portion Pa1 and a storage engagement portion Pa2 are formed to engage the cam follower 28a and the cam follower 30a when the system is in the storage position. The lens cam groove 27b1 and the barrier cam groove 27b2 extend forward while being inclined (relative to the direction of the photographing optical axis Z1) from the engaging portions Pa1 and Pa2 when stored, and slightly forward from the front end portion of the inclined portion. Are formed with a wide end engaging portion Pb1 and a wide end engaging portion Pb2, which are engaged with the cam follower 28a and the cam follower 30a, respectively, when the photographing optical system is located at the wide end position. The lens cam groove 27b1 and the barrier cam groove 27b2 extend substantially parallel to the circumferential direction of the cam ring 27 from the wide end engaging portions Pb1 and Pb2, and then incline (relative to the photographing optical axis Z1 direction). Tele-end engagement portion Pc1 and tele-end that extend forward and slightly forward from the front end of the inclined portion engage with cam follower 28a and cam follower 30a, respectively, when the imaging optical system is located at the tele-end position. An hour engagement portion Pc2 is formed.

As shown in FIG. 5, the engaging portion Pa1 (center point) when retracted is separated by Da from the engaging portion Pa2 (center point) when retracted, and the center point of the wide end engaging portion Pb1 (center point). ) Is separated from the wide end engagement portion Pb2 (the center point) by Db, and the tele end engagement portion Pc1 (the center point) is ahead of the tele end engagement portion Pc2 (the center point). Is separated by Dc. Where Da, Db, Dc are
The relationship is Da = Dc <Db.
Therefore, the distance in the photographic optical axis Z1 direction between the front surface of the decorative ring 29f and the first lens group L1 (the front surface thereof) when the photographic optical system (zoom lens barrel 10) is located at the storage position is LA, and the photographic optical system (zoom). The distance in the photographic optical axis Z1 direction between the front surface of the decorative ring 29f and the first lens group L1 (the front surface thereof) when the lens barrel 10) is positioned at the wide end position is LB, and the photographic optical system (zoom lens barrel 10) is When the distance in the photographic optical axis Z1 direction between the front surface of the decorative ring 29f and the first lens unit L1 (the front surface thereof) at the tele end position is LC,
LA = LC> LB
(See FIG. 6).

Therefore, the zoom lens barrel 10 of the present embodiment can exhibit the following functions and effects.
That is, when the photographic optical system is located at the wide end position, the first lens unit L1 approaches the ornamental ring 29f (lens barrier mechanism 29), so the angle of view of the first lens unit L1 is large. Nevertheless, the effective light beam incident on the first lens unit L1 is not vignetted by the barrier frame 29a (barrier opening). On the other hand, when the photographing optical system is located at the tele end position, the first lens unit L1 is largely separated rearward from the decorative ring 29f (lens barrier mechanism 29), so that a large hood effect by the barrier frame 29a is obtained. (The harmful rays can be prevented from entering the first lens unit L1) and the angle of view of the first lens unit L1 is reduced, so that the effective light beam incident on the first lens unit L1 is reflected on the barrier stage. No vignetting by the frame 29a (barrier opening).

In order to obtain a large hood effect when the photographing optical system is located at the tele end position (the first lens unit L1), the length of the lens cam groove 27b1 in the photographing optical axis Z1 direction and the barrier cam groove 27b2 A large difference is provided between the lengths in the photographing optical axis Z1 direction, and the front-rear distance between the front surface of the decorative ring 29f and the first lens group L1 (the front surface thereof) at the tele end position may be as large as possible (that is, LC> LA). do it).
However, in this embodiment, since LC> LA is not satisfied, LA = LC (the front-rear distance between the front surface of the decorative ring 29f at the tele end position and the front surface of the first lens unit L1), and the decorative ring 29f at the storage position. Since the front-rear distance between the front surface and the first lens group L1 (the front surface thereof) is the same, the front-rear distance between the front surface of the decorative ring 29f and the first lens group L1 (the front surface thereof) at the tele end position is extremely large. There is no. Further, as shown in FIG. 5, the housing engaging portion Pa1 (part) and the housing engaging portion Pa2 (part) are positioned on a straight line extending in the circumferential direction of the cam ring 27, and The end-time engaging portion Pc1 (a part thereof) and the tele end-time engaging portion Pc2 (a part thereof) are positioned on a straight line extending in the circumferential direction of the cam ring 27. Therefore, the difference between the length of the lens cam groove 27b1 in the direction of the photographing optical axis Z1 and the length of the barrier cam groove 27b2 in the direction of the photographing optical axis ZI is almost eliminated (decreased). ) It is possible to make a useless space extremely small (the cam ring 27 can be used effectively).
Further, since LA = LC, the front end position of the barrier cam groove 27b2 is not greatly shifted forward from the front end position of the lens cam groove 27b1. Therefore, it is possible to make the dimension of the cam ring 27 and the zoom lens barrel 10 (and the entire camera) in the retracted state in the direction of the photographing optical axis Z1 as small as possible.
Since LA> LB (since LA is increased to some extent), it is possible to reliably prevent the inner barrier blade 29b and the outer barrier blade 29c from interfering with the first lens unit L1 in the stored state.

As mentioned above, although this invention was demonstrated using the said embodiment, this invention is not limited to the said embodiment.
For example, the storage engagement portion Pa1 (the center point) and the storage engagement portion Pa2 (the center point) are positioned on a straight line extending in the circumferential direction of the cam ring 27 (and the tele end engagement portion Pc1 ( LA = LC> LB after the tele-end engaging portion Pc2 (the center point) is positioned on a straight line extending in the circumferential direction of the cam ring 27). In this way, it is possible to further reduce the dimensions of the cam ring 27 and the zoom lens barrel 10 (and the entire camera) in the retracted state in the direction of the photographing optical axis Z1.
Further, the storage engagement portion Pa1 (part) and the storage engagement portion Pa2 (part) are not positioned on a straight line extending in the circumferential direction of the cam ring 27 (and the tele end engagement portion). (Pc1 (part) and tele end engagement part Pc2 (part) are not positioned on a straight line extending in the circumferential direction of the cam ring 27), and storage engagement part Pa1 (entire) and storage One of the engaging portions Pa2 (entire) may be positioned forward relative to the other (and one of the tele end engaging portion Pc1 (entire) and the tele end engaging portion Pc2 (entire). In front of the other).
Further, the lens cam groove 27b1 may be formed on one of the inner peripheral surface and the outer peripheral surface of the cam ring 27, and the barrier cam groove 27b2 may be formed on the other.

10 Zoom lens barrel 11 Infrared cut filter 12 CMOS sensor (solid-state imaging device)
13 Fixed ring 13a Female helicoid 13b Straight guide groove 14 Image sensor holder 17 AF lens frame (fourth group frame)
18 AF guide shaft 19 AF motor 20 AF nut 22 Zoom gear (long pinion)
23 Zoom motor 24 Gear train 25 Helicoid ring (first advance / retract cylinder)
25a Male helicoid 25b Circumferential guide groove 25c Rotational transmission groove 26 Straight guide ring 26a Radial protrusion 26b Guide protrusion 26c Cam groove 27 Cam ring 27a Follower 27b1 Lens cam groove 27b2 Barrier cam groove 27c Internal cam groove 28 Group 1 frame ( Lens support frame)
28a Cam follower (camera follower on the lens side)
29 Lens barrier mechanism 29a Barrier frame (barrier support member)
29b Inner barrier blade 29c Outer barrier blade 29d Torsion spring 29e Barrier presser plate (barrier support member)
29f Decorative ring (barrier support member)
30 Barrier support cylinder (3rd retreat cylinder)
30a Cam follower (barrier cam follower)
31 Second group frame 32 Second advancing / retracting cylinder 33 Third group support ring 34 Shutter 35 Spring receiving annular plate 36 37 Intergroup spring (compression coil spring)
38 Axial moving diaphragm ring 40 Anti-vibration base 41 Shaft 42 Third group frame L1 First lens group (front end lens)
L2 Second lens group L3 Third lens group L4 Fourth lens group Pa1 Pa2 Engagement portion Pb1 Pb2 Engagement portion Pc1 Pc2 Tele end engagement portion Z1

Claims (3)

An imaging optical system in which the front end lens gradually moves forward along the optical axis in the order of the storage position, the wide end position, and the tele end position;
A lens support frame for supporting the front end lens;
A barrier support member that is positioned immediately before the front end lens, changes the position in the optical axis direction according to the position of the front end lens, and has a barrier opening located on the optical axis;
The barrier support member that closes the barrier opening when the photographing optical system is located at the storage position, and that opens the barrier opening when the photographing optical system is located between the wide end position and the tele end position. Barrier blades supported by
A lens cam groove that engages a lens side cam follower that moves together with the lens support frame, and a barrier cam groove that engages a barrier side cam follower that moves together with the barrier support member, and the optical axis A cam ring that advances and retracts the lens support frame and the barrier support member in the optical axis direction by rotating around,
With
The distance in the optical axis direction between the front surface of the barrier support member and the front end lens when the photographing optical system is located at the storage position is LA,
The optical axis direction distance between the front surface of the barrier support member and the front end lens when the photographing optical system is located at the wide end position is LB,
LC in the optical axis direction distance between the front surface of the barrier support member and the front end lens when the photographing optical system is located at the tele end position,
And when
LA = LC> LB
A collapsible lens barrel characterized by the above relationship. The retractable lens barrel according to claim 1,
When the front end lens is located at the storage position, Pa1 is a portion of the lens cam groove to which the lens side cam follower is engaged, and Pa2 is a portion of the barrier cam groove to which the barrier side cam follower is engaged.
When the front end lens is positioned at the tele end position, Pc1 is a portion of the lens cam groove to which the lens side cam follower is engaged, and Pc2 is a portion of the barrier cam groove to which the barrier side cam follower is engaged.
And when
A retractable lens barrel in which the separation distance in one direction along the optical axis of Pa2 viewed from Pa1 and the separation distance in one direction of Pc2 viewed from Pc1 are the same. The retractable lens barrel according to claim 2,
The cam ring is an annular member centered on the optical axis;
A retractable lens barrel in which a part of Pa1 and a part of Pa2 are arranged in the circumferential direction of the cam ring, and a part of Pc1 and a part of Pc2 are arranged in the circumferential direction.

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