JP4657850B2 - Light blocking structure for zoom lens barrel - Google Patents

Description

The present invention relates to a light blocking structure for a zoom lens barrel.

  In a zoom lens barrel, it is widely performed that a lens frame supporting each lens group is guided straight in the optical axis direction. Various types of linear guide mechanisms have been proposed. Basically, a linear guide groove parallel to the optical axis is formed on the fixed member, and a linear guide protrusion that fits in the linear guide groove on the movable member (lens frame). Is forming.

  In recent zoom lens barrels, there is a case where the straight guide groove is a through groove in order to reduce the size and the diameter, and harmful light may enter through the through groove. In other words, in the zoom lens barrel, the relative positions in the optical axis direction of the plurality of lens frames change with zooming. Depending on the relative positions, harmful light that is not related to shooting reaches the imaging surface from the through groove and damages the image. There was a fear. Conventionally, this light blocking structure has been applied to prevent the entry of harmful light, but the relative position in the optical axis direction of multiple lens frames changes due to zooming. It was difficult to get.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a light shielding structure capable of light shielding the entire zoom range with a simple light shielding member in a zoom lens barrel in which a through groove is formed in a lens frame.

  The present invention coaxially arranges an outer lens barrel, a middle lens barrel having a through-groove that is relatively movable with respect to the outer lens barrel, and an inner lens barrel that is relatively movable with respect to the middle lens barrel in order of increasing diameter. In the zoom lens barrel, a projection is formed on the outer peripheral surface of the inner barrel so as to be relatively movable in the through groove of the middle barrel, and the annular portion is fixed to the inner barrel. A light-shielding member having a plurality of light-shielding elastic tongue pieces that project radially from the annular portion and pass through the through-grooves of the middle lens barrel and the tip portion can contact and contact the inner peripheral surface of the outer lens barrel It is characterized by the provision of a seat.

  In the light shielding structure of the present invention, a light shielding sheet deformation frame that moves relative to the middle lens barrel and the outer lens barrel during zooming is positioned between the middle lens barrel and the outer lens barrel. Particularly useful in a zoom lens barrel that, when in contact with the light shielding elastic tongue of the light shielding sheet, elastically deforms the light shielding elastic tongue from the contact state with the outer barrel to the contact state with the light shielding sheet deformation frame. .

  The present invention can be applied both when the through-groove of the middle lens barrel is a non-linear cam groove and when it is a straight guide groove parallel to the optical axis.

  In the zoom lens barrel of the present invention, specifically, the outer barrel may be a cam ring that is driven to rotate and drives the middle barrel, the inner barrel, and the light shielding sheet deformation frame in a predetermined locus. it can.

  The light shielding sheet deformation frame has a double cylinder structure, and a cam ring can be positioned between the inner cylinder and the outer cylinder. The light-shielding elastic tongue piece of the light-shielding sheet is elastically deformed by the inner cylinder of the light-shielding sheet deformation frame having the double cylinder structure.

  In one aspect of the present invention, the light shielding sheet deformation frame, the middle lens barrel, and the inner lens barrel are each moved in one group, which respectively supports the first lens group, the second lens group, and the third lens group that are positioned in order from the object side. A frame, a second group moving frame, and a third group moving frame can be used.

  Further, the through-groove of the middle barrel can be a groove that guides the light-shielding sheet deformation frame and the inner barrel, and the projection of the inner barrel that fits slidably in the through-groove of the middle barrel is light-shielded. It can be engaged with the sheet deformation frame.

  According to the present invention, in order from the large diameter, the outer lens barrel, the middle lens barrel having a through groove that can move relative to the outer lens barrel, and the inner lens barrel that can move relative to the middle lens barrel, In a zoom lens barrel having a coaxial, and forming a protrusion on the outer peripheral surface of the inner barrel that is relatively movably fitted in the through groove of the middle barrel, the inner barrel is fixed to the inner barrel A light-shielding sheet having a fixing portion and an elastically deformable light-shielding elastic tongue piece that protrudes in a radial direction from the fixing portion and passes through a through groove of the middle lens barrel and has a tip portion that contacts the inner peripheral surface of the outer lens barrel is provided With this simple configuration, harmful light can be prevented from reaching the imaging surface from the through groove in the entire zoom range.

  The illustrated embodiment is an embodiment in which the present invention is applied to a zoom lens barrel proposed by the present applicant in Japanese Patent Application No. 2003-27341. First, the overall structure of the zoom lens barrel will be described with reference to FIGS. As shown in FIG. 1, the optical system of the zoom lens barrel includes, in order from the object side, a first lens unit L1 having a positive power, a second lens unit L2 having a negative power, and a third lens unit having a positive power. This is a varifocal lens system including L3 and the fourth lens unit L4 having a positive power. The zooming is performed by the first to third lens units L1 to L3, and the focal point movement accompanying the zooming is corrected by the fourth lens unit L4. At the time of zooming, the first lens unit L1 and the third lens unit L3 move together at a constant interval. The fourth lens group L4 is a focus group at the same time. FIG. 1 depicts both a zooming trajectory and a trajectory during storage.

  For example, as shown in FIG. 8, a female helicoid 11 a and a rectilinear guide groove 11 b in a direction parallel to the optical axis O are formed in the fixed cylinder 11 fixed to the camera body. As shown in FIG. 9, a male helicoid 12a formed at the rear end of a cam helicoid ring (cam ring, outer barrel) 12 is screwed into the female helicoid 11a of the fixed cylinder 11. A spur gear 12b is formed at the peak of the male helicoid 12a, and the spur gear 12b is positioned in the inner surface recess 11c (FIG. 3) of the fixed cylinder 11 and is rotatably supported (FIG. 15). Always see).

  Accordingly, when the cam helicoid ring 12 is rotated via the drive pinion 13 and the spur gear 12b, the cam helicoid ring 12 moves in the optical axis direction according to the male helicoid 12a and the female helicoid 11a. In the zoom lens barrel of this embodiment, the cam helicoid ring 12 is the only rotating member with the optical axis O as the center.

  A rectilinear guide ring 14 is fitted on the outer periphery of the cam helicoid ring 12. The rectilinear guide ring 14 has a radial rectilinear guide projection 14a on the outer surface of the rear end portion, and a bayonet projection 14b (FIG. 4) on the inner surface of the rear end portion. The rectilinear guide protrusion 14a is fitted in the rectilinear guide groove 11b of the fixed cylinder 11 so as to be relatively movable, and the bayonet protrusion 14b is a circumferential groove formed immediately before the male helicoid 12a (spur gear 12b) of the cam helicoid ring 12. It fits in 12c so as to be relatively rotatable. Therefore, the linear guide ring 14 moves together with the cam helicoid ring 12 in the optical axis direction without rotating.

  On the outer peripheral surface of the cam helicoid ring 12, as shown in FIGS. 4, 9, and 16, a cam groove C15 for the first group moving frame (shading sheet deformation frame) 15 that supports the first lens group L1, and a decoration A cam groove C16 for the cylinder 16 is formed, and a cam groove C17 (see FIG. 19) for the second group moving frame (medium lens barrel) 17 supporting the second lens group L2 is formed on the inner peripheral surface. ing.

  The first group cam groove C15 and the decorative cylinder cam groove C16 are slightly different in shape, and are formed in three pieces spaced apart in the circumferential direction, and the second group cam groove C17 has the same basic locus in the circumferential direction and light. Six are formed apart from each other in the axial direction. The first group moving frame 15, the decorative cylinder 16, and the second group moving frame 17 are each guided in a straight line in the optical axis direction, and follow the first group cam groove C15, the decorative cylinder cam groove C16, and the second group cam groove C17. As the cam helicoid ring 12 rotates, it advances and retreats in the optical axis direction.

  These straight-ahead guidance relationships will be described. As shown in FIGS. 4 and 5, the first group moving frame 15 has a U-shaped cross section having an outer cylinder 15X, an inner cylinder 15Y, and a flange wall 15Z connecting the outer cylinder 15X and the tip of the inner cylinder 15Y. The cam helicoid ring 12 is located between the outer cylinder 15X and the inner cylinder 15Y. A cam follower 15a that fits in the first group cam groove C15 of the cam helicoid ring 12 is fixed to the rear end portion of the outer cylinder 15X. As shown in FIGS. 8 and 9, a first group frame 24 to which the first lens group L1 is fixed is screwed and fixed to the distal end portion of the inner cylinder 15Y. The first group frame 24 can be used when zooming adjustment is performed by adjusting the position of the first lens group L1 in the optical axis direction.

  The rectilinear guide grooves 14c (FIG. 9) parallel to the optical axis O are formed at approximately 120 ° intervals on the inner peripheral surface of the rectilinear guide ring 14 guided linearly by the fixed cylinder 11. The rectilinear guide grooves 14c Further, a rectilinear guide protrusion 15b that protrudes in the radial direction from the rear end portion of the outer cylinder 15X is fitted. The outer cylinder 15X of the first group moving frame 15 is formed with a narrow rectilinear guide groove 15d (FIG. 16) at the rear end of the assembly groove 15c. The rectilinear guide groove 15d is linearly moved with the outer cylinder 15X. A rectilinear guide key 16a fixed to the decorative cylinder 16 located between the guide rings 14 is located.

  The relative movement distance between the first group moving frame 15 and the decorative cylinder 16 in the optical axis direction (the difference in the shapes of the first group cam groove C15 and the decorative cylinder cam groove C16) is slight, and the optical axis direction of the rectilinear guide groove 15d is small. The length of is correspondingly short. The linear guide key 16a is integrally provided with a cam follower 16b that fits into the decorative cylinder cam groove C16.

  A compression coil spring 19 (see FIGS. 3 to 5) is inserted between the first group moving frame 15 and the decorative cylinder 16. The compression coil spring 19 moves and energizes the first group moving frame 15 rearward and the decorative cylinder 16 forward, and between the first group cam groove C15 and the cam follower 15a, and the decorative cylinder cam groove C16 and the cam follower 16b. It works to take backlash between.

  Further, as shown in FIG. 16, the first group cam groove C <b> 15 and the decorative cylinder cam groove C <b> 16 are arranged so that the decorative cylinder 16 (FIG. 3) is located with respect to the first group moving frame 15 in the storage position compared to the shooting position. The shape is set slightly different from the front so as to prevent interference between the barrier of the barrier block 30 (FIG. 8) and the first lens unit L1. In the storage position shown in FIG. 3, the clearance between the flange wall 15Z at the front end of the first group moving frame 15 and the flange wall of the decorative cylinder 16 positioned in front of the flange wall 15Z in the photographing state shown in FIG. 4 or FIG. It can be seen that the clearance is larger than the clearance between both flange walls. In other words, vignetting by the barrier block 30 is prevented by bringing the barrier block 30 closer to the first lens unit L1 at the photographing position. The barrier block 30 is supported by the front end of the decorative cylinder 16, and the barrier opening / closing ring 31 (FIG. 9) positioned immediately behind the barrier block 30 is rotated by the cam helicoid ring 12 in the vicinity of the storage position. Open and close the barrier. A barrier mechanism that opens and closes the barrier block 30 by the rotational movement of the barrier opening and closing ring 31 is well known.

  The front end of the decorative cylinder cam groove C16 is opened, and the cam follower 16b of the decorative cylinder 16 is inserted into the cam groove C16 from the open end C16a (FIG. 16) at a specific assembly position. The Similarly, for the first group cam groove C15, the cam follower 15a of the first group moving frame 15 is inserted from the front end open end C15a.

  The inner cylinder 15Y of the first group moving frame 15 is formed with three rectilinear guide protrusions 15f (FIGS. 6 and 7) in the direction parallel to the optical axis O on the inner peripheral surface thereof. Are formed with three rectilinear guide through grooves 17a in a direction parallel to the optical axis O into which the rectilinear guide protrusions 15f are slidably fitted. A suspension groove 15e in a direction parallel to the optical axis O is formed at the center of the straight guide protrusion 15f, and the rear end of the suspension groove 15e is closed by a circumferential wall 15e '(FIG. 17). , FIG. 18, FIG. 20, FIG. 22, and FIG. 23). The second group moving frame 17 is formed with a cam follower 17c that fits into the second group cam groove C17 of the cam helicoid ring 12.

  On the inner periphery of the second group moving frame 17, a third group moving frame (inner barrel) 18 supporting the third lens group L3 is located. The third group moving frame 18 is formed with a rectilinear guide protrusion 18a parallel to the optical axis O that is slidably fitted into the rectilinear guide through groove 17a of the second group moving frame 17 from the inside. A straight key (stopper protrusion) 18b (FIGS. 11, 17, and 18) is formed at the tip of the third group moving frame 18 so as to be positioned at the center of the linear guide protrusion 18a. Yes.

  As shown in FIG. 11, a shutter block 20 is inserted into the third group moving frame 18 so as to be positioned in front of the third lens group L3, and is fixed by a holding ring 20a. A compression coil spring 21 is inserted between the third group moving frame 18 (restraining ring 20 a) and the second group moving frame 17, and the third group moving frame 18 is always in relation to the second group moving frame 17. Is urged to move backward.

  The rearward movement end of the third group moving frame 18 is restricted at a position where the straight key 18b contacts the rear end of the hanging groove 15e of the first group moving frame 15. In other words, in the shooting state, the state where the straight key 18b is in contact with the rear end of the suspension groove 15e of the first group moving frame 15 is maintained, and the relative distance between the first lens group L1 and the third lens group L3 is constant. It becomes. When the zoom lens barrel changes from the photographing state to the retracted state, after the third lens unit L3 (the third group moving frame 18) reaches the mechanical retracted end, the first lens unit L1 moves to the first group cam. When further retracting according to the groove C15, the compression coil spring 21 is bent and the first lens unit L1 approaches the third lens unit L3 (see FIG. 1). The straight key 18b has a swelled head and is prevented from falling off the hanging groove 15e.

  The compression coil spring 21 may be directly applied to the second group moving frame 17 (the second lens group L2 may be fixed to the second group moving frame 17), but in the illustrated embodiment, the storage length is further reduced. Therefore, the second lens group L2 can be retracted with respect to the second group moving frame 17. FIG. 12 and FIG. 13 show the configuration. The second group moving frame 17 is formed with a cylindrical portion 17e having an inner flange 17d at the tip, and the cylindrical portion 17e has an optical axis. Three rectilinear guide grooves 17f that are parallel to O and open at the rear and front ends are formed at equiangular intervals in the circumferential direction. The cylindrical portion 17e is fitted with a flange portion 25a formed on the intermediate cylindrical member 25, and three radially outward guide projections 25d are provided on the outer peripheral surface of the flange portion 25a so as to protrude at equal angular intervals in the circumferential direction. Are fitted into the corresponding straight guide grooves 17f from the rear. For this reason, the intermediate cylinder member 25 is restricted from relative rotation around the optical axis with respect to the second group moving frame 17, and can be relatively moved only in the optical axis direction. The front surface of the flange portion 25a is the rear surface of the inner flange 17d. It can move forward until it comes into contact.

  The second lens group L2 is fixed to the second group frame 26, and the male screw 26b of the second group frame 26 is screwed into a female screw 25e formed on the inner periphery of the intermediate cylinder member 25. Therefore, by rotating the second group frame 26 relative to the intermediate cylinder member 25 whose rotation about the optical axis is restricted, the position of the second lens group L2 in the optical axis direction can be adjusted (zooming adjustment). After the adjustment, the second group frame 26 can be fixed to the intermediate cylinder member 25 by dropping the adhesive from the adhesive hole 25b.

  Between the front end face of the inner flange 17d of the second group moving frame 17 and the outer flange 26a of the second group frame 26, there is a gap C2 (FIG. 13) including the adjustment allowance. The compression coil spring 21 acts on the intermediate cylinder member 25, and normally, the intermediate cylinder member 25 is held at a position where the flange portion 25a abuts against the inner flange 17d. That is, the position of the second lens group L2 is controlled by the second group cam groove C17 in the shooting state, while the second group frame 26 is mechanically pushed backward by the rear end of the first group frame 24 during storage. The outer flange 26a can be retracted to a position where it abuts against the inner flange 17d, and the storage length corresponding to the gap C2 can be shortened.

  A light shielding frame 27 is supported on the intermediate cylinder member 25. The light-shielding frame 27 includes an annular light-shielding portion 27a, a holding leg 27b extending forward from the annular light-shielding portion 27a at an interval of approximately 120 °, and a retaining hook portion 27c that is bent outward at the tip end portion of the holding leg 27b. The intermediate cylinder member 25 is formed with a light shielding member holding hole 25c into which the retaining hook portion 27c is fitted (FIG. 12).

  A conical coil spring 28 is inserted between the light shielding frame 27 and the second group frame 26, and always urges the light shielding frame 27 to move backward. When the light shielding frame 27 reaches the mechanical retracted end when the lens barrel is housed, the light shielding frame 27 bends the conical coil spring 28 and approaches the second group frame 26. The length of the light shielding member holding hole 25c in the optical axis direction is set so that the annular light shielding portion 27a can come into contact with the second lens unit L2.

  The conical coil spring 28 further functions to remove backlash during zooming adjustment performed by rotating the second group frame 26. The zooming adjustment is an adjustment performed by adjusting the position in the optical axis direction of the second lens unit L2 while observing the image position, and backlash with respect to the intermediate cylinder member 25 (second group moving frame 17) of the second group frame 26 is performed. By removing, accurate adjustment can be made.

  The fourth lens group L4 is fixed to the fourth group frame 22. As described above, the fourth lens group L4 has a role of correcting the focal movement of the varifocal lens system and a role of the focus lens group, and is advanced and retracted by the pulse motor 23. That is, the drive shaft of the pulse motor 23 is a screw shaft 23a, and a nut member 23b whose rotation is restricted is screwed onto the screw shaft 23a. The nut member 23b is constantly urged to move in a direction in which the nut member 23b abuts on the foot portion 22a of the fourth group frame 22 by the spring means S (FIG. 15), and the fourth group frame 22 engages with the radial arm 22c. The rotation is restricted by the bar 22b. Therefore, when the pulse motor 23 is driven, the fourth group frame 22 (fourth lens group L4) moves forward and backward in the optical axis direction. The pulse motor 23 is controlled according to focal length information and subject distance information.

  Therefore, in the zoom lens barrel configured as described above, when the cam helicoid ring 12 is rotated via the drive pinion 13, the first group moving frame 15, the decorative cylinder 16, and the second group moving frame 17 which are guided in a straight line are cam grooves. It moves in the optical axis direction according to C15, C16, C17. The third group moving frame 18 moves together with the first group moving frame 15 when the first group moving frame 15 moves forward from the storage position and the rectilinear key (stopper projection) 18b comes into contact with the rear end of the suspension groove 15e. The position of the fourth lens unit L4 is controlled by a pulse motor 23 that is controlled according to the focal length information, and the focal movement of the varifocal lens system is corrected. As a result, a zooming locus as shown in FIG. 1 is obtained. The pulse motor 23 is also controlled by subject distance information, and a focusing operation is executed.

  In the zoom lens barrel described above, the rectilinear guide protrusion 18a formed on the third group moving frame 18 is slidably fitted in the rectilinear guide through groove 17a formed on the second group moving frame 17, and the front end portion of the rectilinear guide protrusion 18a is slidably fitted. The stopper protrusion 18b formed so as to protrude in the direction passes through the straight guide through groove 17a and is fitted into a suspension groove 15e which is a through hole of the first group moving frame 15. The first group moving frame 15 is formed with an assembly groove 15c and a rectilinear guide groove 15d which are through holes. The second group moving frame 17 has a rear end open through groove 17g (see FIGS. 12, FIG. 20, FIG. 21) are formed. For this reason, there is a possibility that harmful light A (FIGS. 24 and 25) may reach the imaging surface through these through holes. The harmful light A is zoomed particularly toward the long focal length side, and easily reaches the imaging surface when the first group moving frame 15, the second group moving frame 17, and the third group moving frame 18 are separated in the optical axis direction.

  In this embodiment, in order to prevent this harmful light A from entering, a light shielding sheet 40 made of a light shielding material is attached to the rear end face of the third group moving frame 18 as shown in FIGS. 20 to 25. . The light shielding sheet 40 is illustrated only in FIGS. 20 to 25 and is not illustrated in FIGS. 1 to 19. As is apparent from FIG. 20, the light shielding sheet 40 has a flat plate shape, an annular portion (fixed portion) 41 centered on the optical axis O, and three light shielding elastic tongues projecting from the annular portion 41 in the radial direction. It has the piece 42 and two light-shielding elastic tongue pieces 43 different from this. The three light shielding elastic tongue pieces 42 correspond to the three rectilinear guide through grooves 17 a of the second group moving frame 17, and the two light shielding elastic tongue pieces 43 pass through the two rear end open penetrations of the second group moving frame 17. It corresponds to the groove 17g. The annular portion 41 is bonded to the rear end surface of the third group moving frame 18, and the light-shielding elastic tongue piece 42 has a length that the front end portion is in contact with the inner peripheral surface of the cam helicoid ring 12 and the cam helicoid ring 12. It has the flexibility to elastically deform when it comes into contact with the inner cylinder 15Y of the small-diameter first group moving frame 15. There is no through hole in the inner peripheral surface of the cam helicoid ring 12 at least in the corresponding portion of the light-shielding elastic tongue piece 42. A reinforcing plate can be bonded to the annular portion 41 as necessary.

  FIGS. 22 and 23 are vertical cross-sectional views of the zoom lens barrel of the light shielding sheet 40 where the light shielding elastic tongue 42 is present (the straight guide through groove 17a portion of the second group moving frame 17). FIG. FIG. 23 shows the maximum extended state. As shown in FIG. 22, at the time of storage, the light-shielding elastic tongue piece 42 can be elastically deformed and stored by the inner cylinder 15Y of the first group moving frame 15 (the portion where the suspension groove 15e exists). When the storage state is shifted to the photographing state, when the rear end portion (circumferential wall 15e ′) of the inner cylinder 15Y of the first group moving frame 15 exceeds the light shielding elastic tongue piece 42, the light shielding elastic tongue piece 42 is in two groups. It protrudes outward from the straight guide through groove 17a of the moving frame 17 and comes into contact with the inner peripheral surface of the cam helicoid ring 12 to prevent entry of harmful light A.

24 and 25 are vertical cross-sectional views of the zoom lens barrel at the portion where the light-shielding elastic tongue 43 of the light-shielding sheet 40 is present (the rear end opening through groove 17g portion of the second group moving frame 17). FIG. State, FIG. 25 shows the maximum extended state. As shown in FIG. 24, at the time of storage, the light shielding elastic tongue 43 can be elastically deformed and stored by the inner cylinder 15 </ b> Y of the first group moving frame 15. When the storage state is shifted to the photographing state, when the rear end of the inner cylinder 15Y of the first group moving frame 15 exceeds the elastic tongue 43, the elastic tongue 43 contacts the inner peripheral surface of the cam helicoid ring 12. Prevent harmful light A from entering. In this way, the harmful light A is blocked by the light shielding elastic tongues 42 and 43 of the light shielding sheet 40 adhered to the third group moving frame 18 without reaching the imaging surface in the entire zoom range. According to the light shielding structure having the above-described configuration, harmful light A entering from the through grooves of the first group moving frame 15 and the second group moving frame 17 is a simple structure in which the light shielding sheet 40 is bonded to the third group moving frame 18. Reaching the imaging surface can be prevented.
Note that the rear end open through groove 17g of the second group moving frame 17 is not completely closed by the light shielding elastic tongue 43, but other lens barrel members enter the portion where the light shielding elastic tongue 43 does not exist. Can be shielded from light.

The zoom lens barrel described in the above embodiment is an example to which the light shielding structure of the present invention is applied. The light-shielding structure of the present invention is coaxial with an outer barrel, a middle barrel that can move relative to the outer barrel and has a through groove, and an inner barrel that can move relative to the middle barrel. Any zoom lens barrel can be used as long as it has a linear guide protrusion parallel to the optical axis that is slidably fitted in these through grooves on the outer peripheral surface of the inner barrel.

It is a figure which shows the zooming basic locus | trajectory of the zoom lens system to which the zoom lens barrel by this invention is applied. FIG. 2 is a half-cut perspective view showing a lens group and its lens frame of the zoom lens system. It is an upper half sectional view in the storage state of the zoom lens barrel according to an embodiment of the present invention. It is an upper half sectional view in the wide end infinity photographing state of the zoom lens barrel. It is a lower half sectional view in the tele end infinity photographing state of the zoom lens barrel. It is sectional drawing which follows the VI-VI line of FIG. It is sectional drawing which follows the VII-VII line of FIG. It is a disassembled perspective view of a part of the zoom lens barrel. It is a disassembled perspective view of the another part. It is a disassembled perspective view around the first group moving frame. It is a disassembled perspective view around the third group moving frame. It is a disassembled perspective view around the second group moving frame. It is an upper half sectional view around the second group moving frame. It is the disassembled perspective view seen from the back surface around the pulse motor supported by a fixed cylinder. FIG. 6 is an exploded perspective view around the fixed cylinder and a fourth lens group. It is an expanded view of the cam groove for 1 group of a cam helicoid cylinder, and the cam groove for a decoration cylinder. It is an expanded view which shows the rectilinear guidance relation of the 1st group movement frame, the 2nd group movement frame, and the 3rd group movement frame. FIG. It is an expanded view which shows the shape of the cam groove for 2 groups of a cam helicoid ring. It is a disassembled perspective view of a part of the zoom lens barrel. It is the figure seen from the back of a 3 group movement frame. It is a longitudinal cross-sectional view of the rectilinear guide groove part of the 2nd group moving frame at the time of accommodation of the zoom lens barrel. It is a longitudinal cross-sectional view in the maximum extension state of the zoom lens barrel. It is the longitudinal cross-sectional view in a cross section different from FIG. 22, FIG. 23 of the light shielding sheet at the time of accommodation of the zoom lens barrel. It is a longitudinal cross-sectional view in the maximum extension state of the zoom lens barrel.

Explanation of symbols

C2 Clearance C15 C16 C17 Cam groove C15a C16a Open end L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group A Noxious light O Optical axis S Spring means 11 Fixed cylinder 11a Female helicoid 11b Straight guide groove 11c Inner surface recess 12 Cam helicoid ring (outer lens barrel)
12a male helicoid 12b spur gear 12c circumferential groove 13 drive pinion 14 rectilinear guide ring 14a rectilinear guide projection 14b bayonet projection 14c rectilinear guide groove 15 first group moving frame (light shielding sheet deformation frame)
15a cam follower 15b rectilinear guide projection 15c assembly groove 15d rectilinear guide groove 15e suspension groove 15e 'circumferential wall 15f rectilinear guide projection 15X outer cylinder 15Y inner cylinder 15Z flange wall 16 decorative cylinder 16a rectilinear guide key 16b cam follower 17 two-group moving frame ( Middle tube)
17a Linear guide through groove 17c Cam follower 17d Inner flange 17e Cylindrical portion 17f Linear guide groove 17g Rear end open through groove 18 Group 3 moving frame (inner lens barrel)
18a Straight guide protrusion 18b Stopper protrusion (straight key)
19 Compression coil spring 20 Shutter block 20a Retaining ring 21 Compression coil spring 22 Fourth group frame 22a Foot 22b Guide bar 22c Radial arm 23 Pulse motor 23a Screw shaft 23b Nut member 24 First group frame 25 Intermediate cylinder member 25a Flange 25b Adhesion Agent hole 25c Light shielding member holding hole 25d Guide projection 25e Female thread 26 Second group frame 26a Outer flange 26b Male screw 27 Light shielding frame 27a Annular light shielding part 27b Holding leg 27c Retaining hook part 28 Conical coil spring 30 Barrier block 31 Barrier opening / closing ring 40 Light shielding Seat 41 Annular part (fixed part)
42 43 Shading elastic tongue

Claims (8)

A zoom lens having, in order of diameter, an outer lens barrel, a middle lens barrel having a through groove that can move relative to the outer lens barrel, and an inner lens barrel that can move relative to the middle lens barrel. In the lens barrel,
On the outer peripheral surface of the inner barrel, a protrusion is formed that fits in the through groove of the middle barrel so as to be relatively movable,
A fixed portion fixed to the inner barrel, a radial portion protruding from the fixed portion, passing through a through groove of the middle barrel, and a tip portion of the inner barrel contacting the inner peripheral surface of the outer barrel A light-blocking structure for a zoom lens barrel, comprising a light-blocking sheet having a light-blocking elastic tongue that can be elastically deformed. 2. The light shielding structure of a zoom lens barrel according to claim 1, wherein a light shielding sheet deformation frame that moves relative to the middle barrel and the outer barrel during zooming is positioned between the middle barrel and the outer barrel. The light-shielding sheet deformation frame is elastic from the contact state with the outer barrel to the contact state with the light-shielding sheet deformation frame when the light-shielding sheet deformation frame contacts the light-shielding elastic tongue piece of the light-shielding sheet. The light blocking structure of the zoom lens barrel to be deformed. 3. The light shielding structure for a zoom lens barrel according to claim 1, wherein the through groove of the middle lens barrel is a straight guide through groove parallel to the optical axis. 4. The zoom lens barrel light shielding structure according to claim 2, wherein the outer lens barrel is a cam ring that is driven to rotate and drives the middle lens barrel, the inner lens barrel, and the light shielding sheet deformation frame in a predetermined locus. Light blocking structure for lens barrel. 5. The light shielding structure for a zoom lens barrel according to claim 4, wherein the light shielding sheet deformation frame has a double cylinder structure, and the cam ring is located between the inner cylinder and the outer cylinder, The light shielding elastic tongue of the sheet is a light shielding structure of a zoom lens barrel that is elastically deformed by the inner cylinder of the light shielding sheet deformation frame of the double cylinder structure. 6. The light shielding structure of a zoom lens barrel according to claim 2, wherein the light shielding sheet deformation frame, the middle lens barrel, and the inner lens barrel are arranged in order from the object side, a first lens group and a second lens. A light blocking structure of a zoom lens barrel that is a first group moving frame, a second group moving frame, and a third group moving frame that respectively support a group and a third lens group. 7. The light shielding structure for a zoom lens barrel according to claim 2, wherein the through groove of the middle lens barrel is a groove for guiding the light shielding sheet deformation frame and the inner lens barrel. . The zoom lens barrel light shielding structure according to any one of claims 2 to 7, wherein the projection of the inner barrel that is slidably fitted in the through groove of the middle barrel engages with the light shielding sheet deformation frame. The light blocking structure of the zoom lens barrel.

Images