JP3490948B2 - Barrier opening and closing device for lens barrel - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a barrier opening / closing device for a lens barrel.

[0002]

2. Description of the Related Art A lens barrel having a storage position in which shooting is not performed separately from a shooting position, and a lens barrier moving force between the shooting position and the storage position is used to open and close a lens barrier. There is. In a conventional barrier opening / closing device, for example, a barrier drive ring rotatable in the circumferential direction is spring-biased to a rotating end for opening the barrier, and when the lens barrel moves from the photographing position to the storage position, the lens barrel It is known that another moving member constituting the above-mentioned structure is configured to be engaged with the barrier drive ring and forcibly rotated at a rotating end against a spring biasing force to close the barrier. When the lens barrel moves from the storage position to the shooting position, the forced moving force of the separate moving member with respect to the barrier drive ring is released, and the barrier drive ring rotates to the biased rotation end to open the barrier. Further, there is known an opening / closing device in which the barrier itself is biased by a spring in the closing direction and the barrier is closed by the closing spring when the barrier drive ring is forcibly rotated by the separate moving member. . In this case, the closing spring that biases the barrier itself is set to be weaker than the spring that biases the barrier drive ring in the barrier opening direction.

In such a barrier opening / closing device, the larger the load of the barrier drive ring and the spring urging the barrier,
The barrier can be opened and closed reliably. On the other hand, the force that drives the barrier against the biasing means should be used to extend and store the lens barrel, so if the load of the biasing means is too large, the lens barrel delivery and storage performance is high. Will affect.

The difference between the photographing position and the storage position of the lens barrel is simply a change in the axial position of the lens barrel. Therefore, in order to rotate the barrier drive ring, the lens barrel must be moved in the axial direction of the moving member. It is conceivable that the moving force of is converted into a rotational force in the circumferential direction. For example, in a conventional barrier opening / closing device, a taper surface inclined with respect to the optical axis direction is formed in each of a rectilinear tube and a barrier drive ring that are linearly guided in the optical axis direction, and the rectilinear tube is engaged by the engagement of the tapered surfaces. There is one that rotates the barrier drive ring by generating a component force in the circumferential direction from the moving force in the optical axis direction. However, converting the moving force in the optical axis direction into the forced moving force in the circumferential direction causes a large loss of force. As described above, it is desirable that the load of the biasing means is large in order to surely operate the lens barrier, but in the state where the power loss is large in the power transmission process from the moving member of the lens barrel to the barrier drive ring,
The load of the urging means cannot be dealt with, and there is a possibility that the performance for storing and delivering the lens barrel may deteriorate. If an attempt is made to increase the moving force of the lens barrel in order to avoid this, an extra load is applied to the lens barrel driving motor and the like.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and does not impair the operating performance of the lens barrel.
An object of the present invention is to obtain a barrier opening / closing device capable of reliably operating a lens barrier.

[0006]

SUMMARY OF THE INVENTION The present invention is provided in a lens barrel that is movable between a photographing position and a storage position where photographing is not performed. At the storage position, a photographing opening in front of the photographing lens is closed by a barrier, and at the photographing position, the barrier is closed. In a barrier opening / closing device that opens, a barrier drive ring that opens and closes the barrier by forward and reverse rotational movements; a drive ring biasing means that biases the barrier drive ring in either forward or reverse directions; A rotating ring that rotates at least when moving between the storage positions; and a lens barrel that engages with each other when moving in one direction between the shooting position and the storage position to resist the drive ring biasing means. Forcibly rotate the barrier drive ring together with the rotary ring in the direction
The barrier drive ring and the rotary ring are provided with a rotation imparting surface and a rotation transmitting surface respectively formed in the axial direction.
According to this barrier opening / closing device, since the barrier drive ring is driven by the rotational force of the rotary ring that rotates in the same circumferential direction as the barrier drive ring, it is possible to minimize the loss of force during power transmission. Therefore, it is possible to increase the load of the biasing means and improve the barrier operation performance, while preventing the movement performance of the lens barrel itself from being impaired.

In this barrier drive device, the rotation imparting surface of the barrier drive ring is formed by the projection extending in the axial direction, and the rotation transmitting surface of the rotary ring is formed as the boundary surface of the concave portion into which the projection in the axial direction can enter. Is preferably provided.

Further, when the lens barrel moves between the photographing position and the storage position, the barrier drive ring and the rotary ring change the rotation phase of each other to change the interval in the optical axis direction to change the distance between the photographing position and the storage position. At the position where the rotary ring does not forcibly rotate the barrier drive ring, the barrier drive ring and the rotary ring are arranged so that the rotation applying surface of the rotary ring and the rotation transmitting surface of the barrier drive ring do not overlap in the optical axis direction. It is preferred that they are spaced apart in the direction. As such a structure in which the barrier drive ring and the rotary ring are brought into contact with and separated from each other in the optical axis direction, for example, the barrier drive ring is positioned outside the rotary ring and guided linearly in the optical axis direction. Straight advancing cylinder; guide pin projecting radially inward from this rectilinear advancing cylinder; and this guide pin formed on the outer peripheral surface of the outer peripheral surface of the rotary ring, and the straight advancing cylinder is rotated by rotation of the rotary ring. It is preferable to have an advancing / retreating guide groove for advancing / retreating in the optical axis direction.

In the barrier opening / closing device described above, the barrier is weaker than the drive ring biasing means for biasing the barrier to either the closed position or the open position in the direction opposite to the biasing direction of the drive ring biasing means. It is preferable to provide a biasing means so that the barrier is moved by the barrier biasing means when the barrier drive ring is rotated against the drive ring biasing means by the rotary ring.

The barrier opening / closing device for the lens barrel of the present invention is also a barrier for opening / closing the photographing opening in front of the photographing lens; at least rotating when the lens barrel moves between the photographing position and the storage position in which no photographing is performed. Rotation ring; A rotatably supported by a straight-moving cylinder whose rotation in the circumferential direction is restricted, and a barrier drive ring that opens and closes the barrier by forward and reverse rotational movements; Rotationally urges this barrier drive ring to a position where the barrier is opened. An opening direction urging means; and a rotation driving surface and a rotation transmitting surface, which are formed in the barrier drive ring and the rotation ring in the axial direction, respectively, which are engageable and disengageable, and rotate when moving from the photographing position to the storage position. The rotation applying surface of the ring and the rotation transmitting surface of the barrier drive ring are engaged with each other, and the barrier drive ring is forcibly rotated in the direction of closing the barrier against the biasing means in the opening direction.

In the barrier opening / closing device according to this aspect, the barrier drive ring has a pressing portion that can be engaged with and disengaged from the barrier, and further has a closing direction biasing means for biasing the barrier to the closing position, which is weaker than the opening direction biasing means. In the shooting position, the pressing portion of the barrier drive ring, which has a biasing means and is held in a position to open the barrier by the opening direction biasing means, pushes the barrier, and the barrier is opened to move from the shooting position to the storage position. When the barrier ring is forcibly rotated by the rotating ring against the opening direction biasing means when moving,
It is preferable that the pressing portion of the barrier drive ring is retracted from the engagement position with the barrier, and the barrier is closed by the closing direction urging means.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In this embodiment, the present invention is applied to a zoom lens for a digital camera. First, the overall structure will be described, and then the characteristic parts of the present invention will be described.

[0013]

[Description of Entire Lens Barrel of this Embodiment] The configuration of the zoom lens barrel of this embodiment will be described with reference to FIGS. 1 and 2. In the following description, a capital letter with parentheses (F) after the number following the member name indicates that the member is fixed, and the same (L) indicates that the member moves straight in the optical axis direction. (RL) indicates that it moves in the optical axis direction while rotating.

In the lens structure of this embodiment, the first lens unit L1 (L) and the second lens unit L2 are arranged in this order from the object side.
(L) and the third lens unit L3 (L), and zooming is performed by moving the first lens unit L1 and the second lens unit L2 along the optical axis along a predetermined locus while changing the distance between them. . The third lens unit L3 includes the first lens unit L
It functions as a focusing lens regardless of the positions of the first and second lens units L2, and is a so-called rear focusing zoom lens system.

A fixed ring 11 (F) is fixed to a housing 10 (F) fixed to the camera body (or constituting a part of the camera body). Fixed ring 11
Has a fine male screw 11a on its outer peripheral surface, and
Female helicoid 11b and linear guide groove 1 formed by cutting out a part of the female helicoid 11b in a direction parallel to the optical axis.
It has 1c. Three straight guide grooves 11c are formed at 120 ° intervals.

In the housing 10, as shown in FIG.
A CCD insertion window 10a, a filter fixing portion 10b, and a focus lens group movement guide 10c are provided. CCD
The insertion window 10a has a CCD 12a fixed to the substrate 12.
A filter 10d such as a low-pass filter is fixed to the filter fixing portion 10b. The focus lens group movement guide 10c is provided with a third unit that is movable in the optical axis direction.
The lens unit L3 is supported, and the moving position of the third lens unit L3 is determined by the rotation direction and the rotation angle (amount) of the feed screw 10e. The rotation angle of the feed screw 10e is pulse-controlled by a pulse motor (encoder).

A rotating ring 13 (RL) is provided outside the fixed ring 11.
, And the internal thread 1 formed on the inner peripheral surface of the rotary ring 13
3a is screwed onto the male screw 11a of the fixed ring 11. The rotary ring 13 has a gear 13b (FIG. 1) on its outer peripheral surface, and is rotationally driven via a pinion (not shown) meshing with the gear 13b. When the rotary ring 13 is driven to rotate, the rotary ring 13 moves in the optical axis direction while rotating according to the female screw 13a.
On the inner surface of the tip of the rotary ring 13, at 120 ° intervals,
The rotation transmission protrusion 13c is formed. Also, the rotary ring 1
On the outer peripheral surface of 3, the cord plate 14 (RL) is provided in the circumferential direction.
(FIG. 1) is fixed, and a brush 15 (F) (same) that is in sliding contact with the code plate 14 is fixed to the housing 10. The cord plate 14 and the brush 15 have a male screw 11
Detecting the rotational position of the rotary ring 13 as digital information and / or analog information by keeping contact with each other regardless of the moving position of the code plate 14 (rotary ring 13) moving forward and backward in the optical axis direction according to a (female screw 13a). Is provided. The female screw 13 a of the rotary ring 13 is a means for rotatably supporting the rotary ring 13 on the fixed ring 11, and
May be supported on the fixed ring 11 so as to be rotatable only by restricting movement in the optical axis direction.

Inside the fixed ring 11, a straight guide ring 16 is provided.
(L) and a cam ring 17 (R) fitted to the outer peripheral surface of the linear guide ring 16 so as to allow relative rotation by restricting movement in the optical axis direction.
L) and a second cam ring 18 (RL) fitted together on the outer periphery of the tip end of the cam ring 17 are fitted together so as to rotate together in the direction of rotation and relatively movable in the direction of the optical axis. That is,
The linear guide ring 16 has an outer flange 16a at its rear end, and a linear guide ring (flange ring) 1 at its front end.
9 (L) is fixed via the retainer ring 20 (L). The cam ring 17 is sandwiched between the outer flange 16a and the linear guide ring 19, and is supported so that relative rotation with respect to the linear guide ring 16 freely moves together in the optical axis direction. There is.

The second cam ring 1 fitted on the tip of the cam ring 17.
Reference numeral 8 denotes a straight guide portion 1 that slidably engages with stopper protrusions 17a formed at 120 ° intervals on the outer peripheral surface of the cam ring 17.
8 a, the cam ring 17 is not rotated relative to the cam ring 17, and is supported so as to be movable only in the optical axis direction. A compression spring 21 for urging the second cam ring 18 to move forward is provided near the stopper protrusion 17a and the straight guide portion 18a.
Is inserted, and the second cam ring 18 is always in contact with the linear guide ring 19. The second cam ring 18 can be retracted while bending the compression spring 21 by the clearance in the optical axis direction between the stopper protrusion 17a and the rectilinear guide portion 18a. It is also possible to tilt only the radial clearance.

On the outer peripheral surface of the cam ring 17, a male helicoid 17b which is screwed into the female helicoid 11b of the fixed ring 11 is formed. A part of the male helicoid 17b is cut off to transmit rotation of the rotary ring 13. A rotation transmission groove 17c is formed parallel to the optical axis into which the protrusion 13c is slidably fitted. On the other hand, on the outer flange 16a of the straight guide ring 16, straight guide protrusions 16b are formed at 120 ° intervals so as to project radially outward and fit into the straight guide grooves 11c of the fixed ring 11.
The rectilinear guide ring 16 is also formed with rectilinear guide through-grooves 16c penetrating in the direction parallel to the optical axis at 120 ° intervals at the same circumferential position as the rectilinear guide projection 16b.

As shown in FIGS. 4 and 5, the linear guide through groove 16c is open at the rear end surface of the linear guide ring 16, and the outer diameter side thereof is the outer flange 16a and the linear guide projection 16b.
Is blocked by. The outer flange 16a is formed with a cam follower insertion groove 16h on the inner diameter side at the same circumferential position as the linear guide projection 16b.

When the combined body of the straight guide ring 16, the cam ring 17, and the second cam ring 18 is engaged with the fixed ring 11 and the rotary ring 13, the introduction portion 1 is inserted into each straight guide groove 11c of the fixed ring 11.
From 1d, the linear guide projections 16b of the linear guide ring 16 are fitted, and the rotary transmission grooves 13c of the cam ring 17 are fitted with the rotary transmission projections 13c of the rotary ring 13 from the introduction portion 17d.
In that state, the female helicoid 11b of the fixed ring 11 and the cam ring 1
The male helicoid 17b of No. 7 is screwed. Further, the male screw 11a of the fixed ring 11 and the female screw 13a of the rotary ring 13 are screwed together.

In the state where the assembly is completed as shown in FIG. 2, when the rotary ring 13 is rotationally driven through the gear 13b, the rotary ring 13 rotates in the optical axis direction while rotating in the threaded relationship between the female screw 13a and the male screw 11a. Moves forward and backward, and at the same time cam ring 17
The rotation is transmitted to the second cam ring 18 mounted on the outer diameter side of the cam ring 17 by the sliding relationship between the rotation transmission protrusion 13c and the rotation transmission groove 17c, and the male helicoid 17b and the female helicoid 11b are screwed together. The movement in the optical axis direction is given by the relation. At this time, the rectilinear guide ring 16 advances and retreats in the optical axis direction without rotating due to the sliding relationship between the rectilinear guide projection 16b and the rectilinear guide groove 11c, and the cam ring 1 that rotates relative to the rectilinear guide ring 16.
7. The second cam ring 18 moves together with the linear guide ring 16 in the optical axis direction.

On the inner peripheral surface of the cam ring 17, there are formed a first group cam groove 17C1 and a second group cam groove 17C2 which are shown in a developed shape in FIG. The first-group cam groove 17C1 and the second-group cam groove 17C2 are formed in the same shape by three pieces at intervals of 120 °.
It has a tele end position and a wide end position. The rotation angle of the cam ring 17 from the stored position to the wide end position is A.

The first lens frame 22 (L) holding the first lens group L1 and the second lens frame 23 (L) holding the second lens group L2 are formed by the cam grooves 17C1 for the first group and the second group. Guided by the cam groove 17C2 and the linear guide through groove 16c of the linear guide ring 16, the linear guide moves in the optical axis direction. The first lens frame 22 is provided with three elastic tongue pieces 22b protruding rearward from the cylindrical portion 22a at 120 ° intervals, and on the elastic tongue pieces 22b, the linear tongue guide groove 16 is formed so as to protrude in the radial direction.
An angular projection 22c slidably fitted to c is formed, and a follower pin 22d protruding in the radial direction is fixedly planted on the angular projection 22c. The angular protrusion 22c is provided in the straight guide groove 16
It is only necessary that the contact portion with c is a parallel flat surface. First
The lens barrel 22e, to which the lens unit L1 is fixed, has a cylindrical portion 22
It is coupled to the inner peripheral surface of a with a screw 22f, and by adjusting the screwing position, the position of the first lens unit L1 in the first lens frame 22 in the optical axis direction can be adjusted. Lens barrel 22e
Has a wave washer 22h sandwiched between it and the flange 22g of the first lens frame 22.
Due to the elasticity of 2h, the lens barrel 22e (the first lens group L
The play in the optical axis direction of 1) is removed.

The second lens frame 23 is provided with three elastic tongue pieces 23b projecting forward from the annular portion 23a at 120 ° intervals. An angular projection 23c is formed so as to be slidably fitted on the angular projection 23c, and a follower pin 23d protruding in the radial direction is planted and fixed on the angular projection 23c. This angular projection 23c
The follower pin 23d is similar to the angular protrusion 22c and the follower pin 22d of the first lens frame 22 except that the direction of the elastic tongue piece 23b is opposite to the direction of the elastic tongue piece 22b. The lens barrel 23e to which the second lens group L2 is fixed has the flange 23 of the second lens frame 23 via the fixing screw 23f.
It is fixed at g. The shutter block 24 is fixed to the flange 23g of the second lens frame 23.
The shutter block 24 has a CC
It has a function of blocking the light flux given to D12a.

The above first lens frame 22 and second lens frame 2
3 is guided linearly by fitting each angular projection 22c and angular projection 23c into the same corresponding linear guide through groove 16c of the linear guide ring 16. And follower pin 2
2d and the follower pin 23d project in the radial direction from the straight-travel guide through groove 16c of the straight-travel guide ring 16, and the straight-travel guide ring 16
Of the cam ring 17 which are fitted to the outer periphery of the cam ring 17 so as to be slidable relative to each other. The first lens frame 22 and the second lens frame 2
3 is fitted into the straight-moving guide ring 16 and the cam ring 17, from the rear end surface of the straight-moving guide ring 16, the angular protrusions 22c and 23
c in the linear guide through groove 16c, and follower pin 22d
And 23d are passed through the cam follower insertion groove 16h, and then fitted into the cam grooves 17C1 and 17C2. In FIG. 3, the hatched areas in the contours of the cam grooves 17C1 and 17C2 are used during assembly (follower pin 2).
2d and 23d pass through) and are not used in the used state.

With the above guide structure, when the rotary ring 13 is rotated, the cam ring 17 and the second cam ring 18 rotate, but the linear guide ring 16 does not rotate, but the linear guide ring 16 and the cam ring 18 do not rotate. 17, the combined body of the second cam ring 18 moves back and forth in the optical axis direction. As a result, the first lens frame 22 (first lens group L1) and the second lens frame 23 (second lens group L2)
However, according to the cam profiles of the first-group cam groove 17C1 and the second-group cam groove 17C2, the air gap is changed between the first group cam groove 17C1 and the second group cam groove 17C2, and the lenses are moved straight in the optical axis direction to perform zooming.

Next, the connecting structure of the rectilinear guide ring 19 and the retainer ring 20 to the tip of the rectilinear guide ring 16 will be described with reference to FIGS. 6 and 7. The straight guide ring 16 has three bayonet claws 16d formed at the tip end thereof in the radial direction at 120 ° intervals, and the small-diameter insertion part 16e is located between the bayonet claws 16d. There is. A small-diameter portion 16f having the same diameter as the small-diameter insertion portion 16e is formed on the back surface of the bayonet claw 16d. The small-diameter portion 16f is positioned on the back surface of the bayonet claw 16d, and the small-diameter portion 16f is cut out in a direction parallel to the axis. A recess 16g is formed.

On the other hand, the straight guide ring 19 is provided on its inner peripheral surface with a rotation restricting convex portion 19a which can be inserted between the small diameter insertion portion 16e and the bayonet claw 16d and is rotatable relative to the small diameter portion 16f after insertion. Are formed at 120 ° intervals. The straight guide ring 19 also has straight guide protrusions 19b formed on the outer peripheral surface thereof at 120 ° intervals that define the circumferential position of the rotation restricting protrusion 19a.

The retainer ring 20 has, on its inner peripheral surface,
From the small-diameter insertion portion 16e of the linear guide ring 16 to the bayonet claw 1
Fixed claws 20a that can be inserted between 6d and are rotatable relative to the small diameter portion 16f after insertion are formed at 120 ° intervals. Further, a claw groove 20b for rotating operation is formed on the front end face.

When fixing the straight guide ring 19 to the tip of the straight guide ring 16, the straight guide ring 19 is fitted in the small diameter insertion portion 16e with the rotation restricting convex portion 19a thereof.
Rotate on the f to rotate the rotation restricting protrusion 19a into the bayonet claw 1
6d is moved to the back surface and fitted into the rotation restricting concave portion 16g. By this fitting, the circumferential position of the linear guide ring 19 with respect to the linear guide ring 16 is determined. Next, the retainer ring 20 is fitted with the fixed claw 20a in the small diameter insertion portion 16e and rotated on the small diameter portion 16f, and the rotation regulating convex portion 19a is pressed against the rotation regulating concave portion 16g to move the linear guide ring 19 in the axial direction. Suppress. In this locked state, the fixed claw 20
a enters between the bayonet claw 16d and the rotation restricting convex portion 19a, and the fixed claw 20a and the bayonet claw 16d prevent the straight guide ring 19 from coming off. Between the rectilinear guide ring 16 and the retainer ring 20, unevenness is provided to prevent the retainer ring 20 from rotating (giving a click feeling) in a locked state. In FIG. 6, only the unevenness 16j on the side of the straight guide ring 16 is shown.

In this way, the linear guide projections 19b of the linear guide ring 19 fixed to the tip of the linear guide ring 16 are
The linear guide ring 16 is at a specific position (angle relationship) that is predetermined with respect to the linear guide protrusion 16b. This straight guide protrusion 1
9b is provided on the inner peripheral surface of the external cylinder (hood cylinder) 25 (L).
Straight guide grooves 2 formed at 0 ° intervals in a direction parallel to the optical axis
It is fitted in 5a and guides only the movement in the optical axis direction without rotating the external appearance cylinder 25. The appearance cylinder 25 has 12
Three guide pins 25b are planted at 0 ° intervals,
The guide pin 25b is mounted on the outer peripheral surface of the second cam ring 18
It fits in the advancing / retreating guide grooves 18b of the same shape formed at intervals of 20 °.

As shown in FIGS. 8 and 9, the advancing / retreating guide groove 18b is provided with an assembling position into which the guide pin 25b is inserted at the time of assembling, a housing position of the cam ring 17, and a housing position corresponding to the tele end position and the wide end position. , The telescopic end position and the wide end position, and moves the external appearance cylinder 25 in the optical axis direction according to the rotational position of the second cam ring 18 that rotates together with the cam ring 17. That is, the appearance cylinder 25 is moved forward with respect to the second cam ring 18 (first lens unit L1) at the tele end position where the angle of view is narrow, and is retracted at the wide end position where the angle of view is wide, thereby functioning as a lens hood. Is given. 10 shows the position of the external appearance cylinder 25 at the wide end position, and FIG. 11 shows the position of the external appearance cylinder 25 at the tele end position.

As described above, the second cam ring 18 is provided between the second cam ring 18 which guides the external appearance cylinder 25 and the cam ring 17 which guides the first lens unit L1 and the second lens unit L2. Since the compression spring 21 that biases the movement is inserted into the external cylinder 25, at least a part of the external force can be absorbed by the compression spring 21 when the external force is applied to the external appearance cylinder 25 during use. That is, the external force is the compression spring 21.
Is transmitted from the second cam ring 18 to the cam ring 17 after being compressed, a large external force is not applied to the cam ring 17. Therefore, the influence on the positional accuracy of the first lens unit L1 and the second lens unit L2 can be reduced. For more detailed movement and action of the external appearance tube 25, see the external appearance tube 22.
After explaining the barrier block 27 fixed to the tip of
Furthermore, it demonstrates using FIG. Reference numeral 29 in FIG.
(F) is a cover tube that is integral with the camera body side, with the outer appearance tube 25 advancing and retracting inside.

A barrier drive ring 26 is rotatably supported at the inner diameter of the front end portion of the external appearance cylinder 25. The barrier drive ring 26 is rotated by the barrier block 27.
It opens and closes the barrier. Barrier block 27
1 and FIGS. 13 to 15, a decorative plate 27b having a photographing opening 27a, two pairs of barriers 27c and 27d supported by the decorative plate 27b so as to open and close the photographing opening 27a, and these barriers. A pair of torsion springs 27e for biasing 27c and 27d in the direction of closing the photographing opening 27a, and a barrier holding plate 27f for sandwiching and holding these elements between them and a decorative plate 27b are assembled in advance as a separate unit. To be The barriers 27c and 27d are rotatable coaxially with a common shaft 27g provided on the decorative plate 27b, and the inner barrier 27d is rotated in the closing direction by a torsion spring 27e that is hooked on a spring hanging shaft 27n of the decorative plate 27b. Being energized. The barrier 27d is formed with an opening / closing projection 27h for opening the barrier 27d against the force of the torsion spring 27e.
When the barrier 27d moves in the opening direction, there is formed an interlocking protrusion 27i that engages the edge portion of the barrier 27d and moves the barrier 27c together with the barrier 27d in the opening direction. Further, the barriers 27c and 27d are provided on the opposite surfaces thereof together with the barrier 27d when the barrier 27d moves in the closing direction.
There are formed interlocking protrusions 27j and 27k (FIG. 15) for moving in the closing direction. The barrier holding plate 27f has an opening / closing protrusion 27.
An exposure hole 27m that allows h to project to the barrier drive ring 26 side is formed.

The barrier drive ring 26 is shown in FIGS.
As shown in FIG. 2, the spring hooking protrusion 26 b formed on the barrier drive ring 26 itself and the spring hooking protrusion 2 formed on the external cylinder 25.
A tension spring 28, which is tighter than the torsion spring 27e and is stretched between the barrier drive ring 26 and 5c, engages the barrier drive ring 26 with the opening / closing projection 27h of the barrier 27d. An opening / closing dowel 26c for opening 27c and 27d is formed. When the barrier drive ring 26 is located at the turning end by the force of the tension spring 28, the opening / closing dowel 26c presses the opening / closing protrusion 27h to open the barrier 27d against the force of the torsion spring 27e, and the interlocking protrusion 27i. 27c is also opened via (FIG. 15).

On the other hand, the barrier drive ring 26 has, as shown in FIG. 16, a rotation transmitting projection 26a projecting toward the second cam ring 18 side in a part of its circumferential direction, and this rotation transmitting projection 26a. Is the rotation imparting recess 1 formed in the second cam ring 18.
8c (see also FIGS. 8 and 9). Barrier drive ring 2
6 is rotatably supported by the external appearance cylinder 25 at a fixed position in the optical axis direction, and therefore, when the external appearance tube 25 moves forward and backward in the optical axis direction according to the advance / retreat guide groove 18b of the second cam ring 18, FIG. As can be seen in FIG. The rotation transmitting protrusion 26a and the rotation imparting recess 1
8c does not contact (engage) with each other at the photographing position (between the tele end position and the wide end position) as in FIG. 8, but as shown in FIG. 9 while moving from the tele end position to the storage position. The barrier drive ring 2 is engaged with each other by the rotation imparting recess 18c.
6 is formed so that a forced rotation force is applied. When the barrier drive ring 26 pivots to the moving end against the tension spring 28, the opening / closing dowel 26c of the barrier drive ring 26 causes the barrier 27 to move.
The barrier 27d is opened by the force of the torsion spring 27e as a result of being separated from the opening / closing protrusion 27h of d.
The barrier 27c is closed via the k and 27j to close the photographing opening 27.
a is closed (FIG. 14). On the contrary, during the transition from the retracted position to the tele end position, the rotation transmission protrusion 26a gradually separates from the rotation imparting recess 18c, and the tension spring 28 causes the barrier drive ring 26 to rotate in the barrier opening direction. 26
c presses the opening / closing protrusion 27h, and the barriers 27c and 27d open via the interlocking protrusion 27i. That is, the barriers 27c, 2
The opening and closing of 7d is performed by rotation of the barrier drive ring 26. It should be noted that the rotation transmitting protrusion 26a formed on the barrier drive ring 26 is unique, whereas the rotation imparting recesses 18c formed on the second cam ring 18 are formed at three intervals of 120 °, and are not formed at any time during assembly. You can choose either.

As described above, the external appearance cylinder 25, which is guided so as to move straight in the optical axis direction, moves back and forth due to the rotation of the second cam ring 18. On the other hand, the first lens group L1 and the second lens group L2 are moved back and forth by the rotation of the cam ring 17. 12 shows the image plane of the CCD 12a, the first lens group L1 and the second lens group L2 (principal point positions thereof), and the barrier block 27 (at the front end of the external appearance cylinder 25) at the storage position, the tele end position to the wide end position. 3 shows a change in the position of the photographing opening 27a) of the decorative plate 27b at the tip of the. Cam ring 1
No. 7 cam grooves 17C1 and 17C2, and the second cam ring 18
The advancing / retreating cam groove 18b is defined so that such a movement locus can be obtained. The photographing opening 27a has a substantially rectangular shape on the front side, and has an angle of view in the short side direction, an angle of view in the long side direction,
The angle of view in the diagonal direction increases in order. In FIGS. 10 and 11, a light flux S incident from the short side direction of the photographing aperture 27a, a light flux M incident from the long side direction, and a light flux L incident from the diagonal direction.
Shows the angle of.

A light-shielding cylinder 26d extending from the barrier drive ring 26 to the outer periphery of the front end of the first lens frame 22 is fixed (bonded) to the inner diameter of the barrier drive ring 26. The light-shielding cylinder 26d has a rotationally symmetric shape about the optical axis, and its light-shielding function does not change even if the barrier drive ring 26 is reciprocally rotated.

All the components constituting the zoom lens barrel described above are molded products of synthetic resin material except for the springs, the feed screw 10e, the fixing screw 23f, the follower pins 22d and 23d, the shutter block 24 and the guide pin 25b. It consists of

In the above embodiments, the third lens group L3 is the focus lens group, but another lens group, for example, the first lens group L1 or the second lens group L2 may be the focus lens group. When the second lens unit L2 is the focus lens unit, the shutter block 24
A focusing function can be provided to the shutter block, and such a shutter block is well known.

[0043]

DESCRIPTION OF CHARACTERISTICS OF THE PRESENT INVENTION As described above, the two pairs of barriers 27c and 27d of the barrier block 27 are the positive and negative portions of the barrier drive ring 26 supported through the external appearance cylinder 25 (straight guide cylinder) guided straight. It is opened and closed according to the rotational movement to the opposite rotational end. At the photographing position, the rotation transmission protrusion 26a of the barrier drive ring 26 and the rotation imparting recess 18 of the second cam ring 18 (rotation ring) are provided.
c is not engaged with each other, and the barrier drive ring 26 is held at a rotating end for opening the barrier by a pair of tension springs 28 (drive ring biasing means, opening direction biasing means). At this time, the pair of torsion springs 2 are attached to the barriers 27c and 27d.
7e (barrier urging means, closing direction urging means) also acts in the closing direction, but since the urging force of the tension spring 28 is stronger, the opening / closing dowel 26c (pressing portion) causes the opening / closing protrusion 27h.
The barrier 2 against the force of the torsion spring 27e.
7d is opened, and the barrier 27c is also opened via the interlocking protrusion 27i. When the lens barrel moves from the photographing position to the storage position, the rotation transmitting protrusion 26a and the rotation imparting recess 18c are engaged with each other as shown in FIG. 9, and the barrier drive ring 26 receives a forced rotational force in the direction to open the barrier. Given. When the barrier drive ring 26 is rotated to the rotation end against the tension spring 28, the pressing of the opening / closing dowel 26c on the opening / closing protrusion 27h is released, and the barrier 27 is biased by the biasing force of the torsion spring 27e.
c and 27d are closed.

That is, in the barrier opening / closing device of this embodiment, the forcible rotational force for rotating the barrier drive ring 26 in the direction of closing the barrier is the rotating member that rotates in the same direction as the barrier drive ring 26. It is provided by the cam ring 18. As shown in FIGS. 8, 9 and 16, the rotation imparting recess 18c of the second cam ring 18 and the rotation transmitting protrusion 26a of the barrier drive ring 26 have a rotation imparting surface 18d and a rotation transmitting surface 26e, which engage with each other. It is formed in the axial direction, and the rotational force of the second cam ring 18 rotating in the circumferential direction can be transmitted to the barrier drive ring 26 without loss.
When attempting to open and close the barrier using the moving force of the moving member that constitutes the lens barrel, the fact that the moving force can be transmitted without loss eventually affects the performance of the lens barrel that is extended and stored. This means that the operating performance of the barrier can be improved. The reason will be explained.

If the moving force of the moving member on the driving side is constant when the barrier drive ring 26 is rotated against the tension spring 28, the loss of the transmitted moving force is small. However, since the forced moving force applied to the barrier drive ring 26 is large, the load of the tension spring 28 can be increased. The stronger the load of the tension spring 28, the stronger the force for opening the barrier, and therefore the response at the time of opening the barrier is good, and the reliable barrier opening operation is guaranteed. For example, the biasing force of the tension spring 28 in the barrier opening direction acts on the opening / closing protrusion 27h near the axial position (the common shaft 27g) in the barrier 27d, and foreign matter such as dust is attached to the tip of the barrier 27d far from the axial position. If the tension spring 28 has a weak force when adhered to, the barrier may not be opened surely, but such malfunction can be avoided by increasing the load of the tension spring 28. Further, since the load of the torsion spring 27e is determined by the relationship with the tension spring 28 (torsion spring 27e <tension spring 28), if the load of the tension spring 28 can be increased,
The load of the torsion spring 27e can be increased accordingly. For the same reason as in the case of the tension spring 28, if the load of the torsion spring 27e is large, the response at the time of closing the barrier is improved, and the reliable barrier closing operation is guaranteed.

As described above, by increasing the load of the spring in the barrier opening / closing device, the operating performance of the barrier can be improved. On the other hand, if the load of the spring is large, the force required to drive the barrier is large, but with the configuration in which the moving force of the moving member forming the lens barrel is transmitted to the barrier drive ring without waste as in the present embodiment. If so, the barrier drive ring can be rotated by a normal lens barrel moving force from the photographing position to the storage position. Therefore, the barrier can be reliably driven without impairing the movement performance of the lens barrel or applying an extra load to the drive source for moving the lens barrel back and forth.

Further, as shown in FIG. 8, when the lens barrel moves from the storage position to the photographing position, the barrier drive ring 26
The distance between the (appearance cylinder 25) and the second cam ring 18 in the optical axis direction is large, and the rotation transmission protrusion 26a (rotation transmission surface 26e) of the barrier drive ring 26 and the rotation imparting recess 18c (rotation imparting surface 18d) of the cam ring 18 are No overlap in the optical axis direction.
The lens barrel of the present embodiment is a zoom lens barrel, and since it is necessary to perform a zoom operation between the tele position and the wide position, the barrier drive ring 26 (exterior barrel 25) and the second cam ring 18 are relatively positioned at the shooting position. To rotate. Therefore, like the present lens barrel, at the photographing position, the rotation transmitting protrusion 26 protruding in the axial direction is formed.
The barrier drive ring 26 and the second cam ring 18 are separated from each other in the optical axis direction so that a does not overlap with the cam ring 18 in the optical axis direction, and the relative rotation of the external appearance cylinder 25 and the second cam ring 18 is hindered. It is desirable not to.

As is clear from the above description, in the barrier opening / closing device of the present invention, the rotating force of the rotary ring is transmitted to the barrier drive ring without waste when the photographing position and the storage position are moved. It is possible to increase the load to improve the barrier operation performance and prevent the lens barrel itself from deteriorating the delivery and storage performance.

Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment.
For example, although the zoom lens barrel has been described in the embodiment, the present invention can be applied to any lens barrel that moves to at least the photographing position and the storage position.

Further, in the embodiment, the barrier drive ring 26 is urged in the direction to open the barrier and is forced in the barrier closing direction by the second cam ring 18 against the urging force only in the storage position of the lens barrel. It is supposed to give movement power. This is because of the structure of the zoom lens barrel in which the barrier drive ring 26 and the second cam ring 18 further rotate relatively in the shooting position between the tele position and the wide position and also move relatively in the optical axis direction. This is because it is not practical to keep the barrier drive ring 26 and the second cam ring 18 engaged at the photographing position. However, from the viewpoint of transmitting the moving force of the rotary ring to the barrier drive ring without loss, the relationship between the biasing direction of the barrier drive ring and the forced moving direction that the rotary ring should impart against the biasing direction. Can be reversed from the embodiment. That is, in principle, at the storage position of the lens barrel, the barrier drive ring and the rotary ring are not engaged, and the barrier is closed by the biasing means that biases the barrier drive ring so that the lens barrel is at the photographing position. When moved, it is also possible to engage the rotary ring with the barrier drive ring to force rotation against the biasing means and to open the barrier in response to the force rotation. in this case,
The biasing means for biasing the barrier itself (corresponding to the torsion spring 27e in the embodiment) may be configured to bias the barrier to the open position, contrary to the above-described embodiment.

[0051]

As described above, according to the present invention, it is possible to obtain a barrier opening / closing device capable of reliably operating the lens barrier without impairing the operating performance of the lens barrel.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing the entire structure of a zoom lens barrel according to the present invention.

FIG. 2 is an upper half sectional view of the same assembled state.

FIG. 3 is a development view of a cam groove of a cam ring.

FIG. 4 is an exploded perspective view showing a relationship among a first lens frame, a second lens frame, a straight guide ring, and a cam ring.

FIG. 5 is a rear view of a straight guide groove portion of the straight guide ring.

FIG. 6 is an enlarged exploded perspective view of a disassembled state of a straight guide ring, a straight guide ring, and a retainer ring.

FIG. 7 is an enlarged exploded development view of the same.

FIG. 8 is a development view showing a positional relationship between a second cam ring and a barrier drive ring in a photographing state (tele end position).

FIG. 9 is a development view showing a positional relationship in the storage state.

FIG. 10 is an upper half cross-sectional view showing the positional relationship between the external cylinder and the second cam ring (first lens group) in the wide-angle shooting state.

FIG. 11 is an upper half cross-sectional view showing the positional relationship between the external appearance cylinder and the second cam ring (first lens group) in the telephoto shooting state.

FIG. 12 is an upper half cross-sectional view showing the positional relationship between the external cylinder and the second cam ring (first lens group) in the telephoto shooting state by a solid line and by the chain line in a wide shooting state.

FIG. 13 is an exploded perspective view of the barrier block seen from the back side.

FIG. 14 is a perspective view of the barrier block excluding the barrier pressing plate as viewed from the rear side in an assembled state.

FIG. 15 is a front view showing a barrier opened / closed state of the barrier block.

FIG. 16 is an exploded perspective view showing the relationship between the rotation imparting recess of the second cam ring and the rotation transmitting protrusion of the barrier drive ring.

FIG. 17 is a front view of the barrier drive ring rotatably supported by the external cylinder at one pivot end (barrier closed position).

FIG. 18 is a front view of the other rotation end (barrier open position) of the barrier drive ring.

[Explanation of symbols]

L1 First lens group L2 Second lens group L3 Third lens group 10 Housing 11 Fixed ring 11a Male screw 11b Female helicoid 11c Straight guide groove 12 Substrate 12a CCD 13 Rotating ring 13a Female screw 13b Gear 13c Rotation transmission protrusion 14 Code plate 15 Brush 16 Straight guide ring 16a Outer flange 16b Straight guide protrusion 16c Straight guide through groove 16d Bayonet claw 16e Small diameter insertion portion 16f Small diameter portion 16g Rotation restriction recess 16h Cam follower insertion groove 17 Cam ring 17a Stopper protrusion 17b Male helicoid 17c Rotation transmission groove 17d Introduction portion 18 2nd cam ring (rotating ring) 18a Straight advance guide part 18b Advancement / retraction guide groove 18c Rotation giving recess 18d Rotation giving surface 19 Straight advance guide ring 19a Rotation restricting convex part 19b Straight advance guide protrusion 20 Retainer ring 20a Fixed claw 20b Claw groove 21 Compression spring 22 First lens frame 22a Cylindrical portion 22b Elastic tongue piece 22c Square protrusion (parallel plane protrusion) 22d Follower pin 22f Screw 22g Flange 22h Wave washer 23 Second lens frame 23a Annular portion 23b Elastic tongue piece 23c Square protrusion (parallel plane) 23d Follower pin 23e Lens barrel 23f Fixing screw 23g Flange 24 Shutter block 25 Appearance barrel (straight barrel) 25a Straight guide groove 25b Guide pin 25c Spring engaging protrusion 26 Barrier drive ring 26a Rotation transmitting protrusion 26b Spring engaging protrusion 26c Open / close dowel (press) 26d Light-shielding cylinder 26e Rotation transmission surface 27 Barrier block 27a Photographing opening 27b Decorative plate 27c 27d Barrier 27e Torsion spring (barrier urging means, closing direction urging means) 27f Barrier pressing plate 27g Common shaft 27h Opening / closing projection 27i 27 j 27k Opening / closing projection 28 Tension spring (driving ring biasing means, opening direction biasing means) 29 Fixed cover cylinder

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Nakamura 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Optical Co., Ltd. (56) Reference JP-A-7-159856 (JP, A) JP HEI 11-15043 (JP, A) JP-A-4-81829 (JP, A) JP-A-2000-35606 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03B 11/04 G03B 17/04

Claims (7)

(57) [Claims] 1. A barrier opening / closing device which is provided in a lens barrel movable between a photographing position and a storage position where photographing is not performed, and closes a photographing opening in front of the photographing lens with a barrier at the storage position and opens the barrier at the photographing position. , A barrier drive ring that opens and closes the barrier by forward and reverse rotational movement; a drive ring biasing means that biases the barrier drive ring in either forward or reverse direction; between the photographing position and the storage position of the lens barrel. A rotation ring that rotates at least when moving in a direction; and a lens barrel that engages with each other when moving in one direction between a shooting position and a storage position and rotates in a direction against the drive ring biasing means. A barrier opening / closing device for a lens barrel, comprising: a barrier driving ring and a rotation imparting surface and a rotation transmitting surface, which are formed on the rotation ring in the axial direction respectively, for forcibly rotating the barrier driving ring together with the ring. 2. The barrier opening / closing device according to claim 1, wherein the rotation-applying surface of the barrier drive ring is formed as a projection extending in the axial direction, and the projection in the axial direction enters the rotation transmitting surface of the rotary ring. A barrier opening / closing device for a lens barrel formed as a boundary surface of a possible recess. 3. The barrier opening / closing device according to claim 1, wherein when the lens barrel moves between the photographing position and the storage position, the barrier drive ring and the rotary ring change their mutual rotation phases. If the rotation ring does not forcibly rotate the barrier drive ring between the shooting position and the storage position by changing the interval in the optical axis direction, the rotation imparting surface of the rotation ring and the rotation transmission surface of the barrier drive ring are overlaid in the optical axis direction. A barrier opening / closing device for a lens barrel in which a barrier driving ring and a rotating ring are separated from each other in the optical axis direction so as not to wrap. 4. The barrier opening / closing device according to claim 3, wherein the barrier opening / closing device is located outside the rotary ring and guided straight in the optical axis direction.
A straight advancing cylinder rotatably supporting the barrier drive ring on its end surface; a guide pin projecting radially inward from the straight advancing cylinder; and this guide pin formed on the outer peripheral surface of the outer peripheral surface of the rotary ring. A barrier opening / closing device for a lens barrel having an advancing / retreating guide groove that engages with the rotating ring to advance / retreat the rectilinear barrel in the optical axis direction. 5. The barrier opening / closing device according to any one of claims 1 to 4, wherein the barrier is attached to one of a closed position and an open position in a direction opposite to a biasing direction of the drive ring biasing means. A barrier biasing means for biasing the drive ring biasing means weaker than the drive ring biasing means, and the barrier biasing means moves the barrier when the barrier drive ring is rotated against the drive ring biasing means by the rotating ring. Barrel opening / closing device for lens barrel. 6. A barrier for opening and closing a photographing opening in front of the photographing lens; a rotary ring that rotates at least when the lens barrel moves between a photographing position and a storage position where photographing is not performed; rotation in a circumferential direction is restricted. It is rotatably supported by the straight advance barrel,
A barrier drive ring that opens and closes the barrier by forward and reverse rotational movements; opening direction urging means that rotationally urges the barrier drive ring to a position where the barrier is opened; and the barrier drive ring and the rotary ring that are formed axially, respectively. A rotation imparting surface and a rotation transmitting surface which are engageable and disengageable, and when moving from the photographing position to the storage position, the rotation imparting surface of the rotating ring and the rotation transmitting surface of the barrier drive ring engage with each other, A barrier opening / closing device for a lens barrel in which a barrier driving ring is forcibly rotated in a direction of closing the barrier against the opening direction urging means. 7. The barrier opening / closing device according to claim 6, wherein the barrier drive ring has a pressing portion that can be engaged with and disengaged from the barrier, and further urges the barrier to a closed position. In the photographing position, the pressing portion of the barrier drive ring, which has a weaker closing direction biasing means and is held at the position where the opening direction biasing means opens the barrier, pushes the barrier, and the barrier is opened. When the barrier drive ring is forcibly rotated against the opening direction biasing means by the rotary ring when moving from the photographing position to the storage position, the pressing portion of the barrier drive ring retracts from the engagement position with the barrier. A barrier opening / closing device for the lens barrel, in which the barrier is closed by the closing direction urging means.