JP3554405B2 - Electric zoom lens barrel - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an electric zoom lens barrel having a zoom operation ring that can be moved in the optical axis direction of a photographing lens and rotated around the optical axis.
[0002]
[Prior art and its problems]
The present applicant has proposed an electric zoom lens barrel capable of switching between electric zooming and manual zooming by moving a zoom operation ring to one and the other movement positions in the optical axis direction (Japanese Patent Application No. 2-28902). No. etc.). In this electric zoom lens, when the zoom operation ring positioned at the neutral position in the free state is manually rotated around the optical axis in one direction (positive direction), zooming is performed toward the telephoto side, and the other (reverse direction). When rotated to zoom in toward the wide angle side.
[0003]
In this electric zoom lens, a rotating annular member (focal point) which is connected to a zoom drive ring for rotating the photographing lens group in the optical axis direction by rotating about the optical axis and having a focal length printed on the outer peripheral surface. On the distance scale ring), an engaging tooth row portion including a plurality of engaging teeth is formed along a part of the rotating member in the circumferential direction. During manual zooming, the engagement tooth row portion meshes with a circumferential tooth row portion formed of a plurality of engagement teeth formed along the inner peripheral surface of the zoom operation ring, thereby rotating the zoom operation ring. Is transmitted to the zoom drive ring, and the engagement with the circumferential tooth row portion is released during electric zooming.
[0004]
In a conventional electric zoom lens having such a configuration, the focal length scale ring is provided with an engagement tooth row portion that meshes with a circumferential tooth row portion formed along the inner peripheral surface of the zoom operation ring. Therefore, the focal length scale ring is configured as an annular member having a certain thickness in terms of strength, particularly when it is made of a resin material, as an annular member having a greater thickness than when it is made of a metal material. Be composed. For this reason, in this conventional electric zoom lens, the focal length scale ring has been an obstacle for downsizing the electric zoom lens.
[0005]
[Object of the invention]
The present invention has been made in view of the above problems, and switches between manual zooming and electric zooming at one and the other movement positions of the zoom operation ring in the optical axis direction, and at the time of this electric zooming, the zoom operation ring. The objective is to reduce the size of an electric zoom lens barrel that changes the zooming speed according to the amount of rotation from a neutral position.
[0006]
Summary of the Invention
The present invention relates to a zoom drive ring rotatable around an optical axis; and a zoom mechanism for moving a photographing lens group along the optical axis direction by a forward / reverse rotation of the zoom drive ring to change a focal length. A zoom operation ring capable of a linear movement operation in the optical axis direction and a rotation operation around the optical axis; a circumferential engagement portion formed on the zoom operation ring along the circumferential direction; A lever member formed of a non-circular member fixed to the drive ring and having an engaging portion at an outer end thereof which engages with and disengages from a circumferential engaging portion of the zoom operating ring; one of the moving positions of the zoom operating ring in the optical axis direction; A manual zoom mechanism that engages the circumferential engagement portion with the engagement portion of the lever member to integrate the zoom operation ring and the zoom drive ring in the circumferential direction; and the other of the zoom operation ring in the optical axis direction. In the moving position, while disengaging the circumferential engaging portion and the engaging portion of the lever member, It is characterized by comprising; an electric zoom mechanism that connects over arm mechanism to the electric drive system.
[0007]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, the present invention will be described based on illustrated embodiments. FIG. 1 shows an electric zoom lens barrel 10 to which the present invention is applied. The zoom lens barrel 10 is a four-group type zoom lens barrel having first to fourth lens groups L1, L2, L3, L4.
[0008]
The zoom lens barrel 10 has, at the rear end of the barrel, a mount ring 11 for detachably fixing to a camera body (not shown). A mount ring 12 is fixed to the mount ring 11, a housing 13 is fixed inside the mount ring 12, a fixed cylinder 14 is fixed inside the housing 13, and fixed to a front end of the housing 13. The outer cylinder 15 is fixed. An aperture ring 16 is provided between the mount ring 11 and the mount connecting ring 12 so as to be rotatable around the optical axis O.
[0009]
A zoom drive ring 22 is rotatably fitted on the outer periphery of the fixed cylinder 14. At the front end of the zoom drive ring 22, a helicoid ring 20 whose rotation around the optical axis O is regulated and guided straight ahead is fitted. The decorative frame 17 is fitted to the front end of the helicoid ring 20. The helicoid ring 20 and the decorative frame 17 are screwed together by screwing a male helicoid 20 a formed on the outer periphery of the helicoid ring 20 and a female helicoid 17 a formed on the inner periphery of the decorative frame 17.
[0010]
A focus ring 28 is fitted to the front end of the fixed outer cylinder 15 so as not to move along the optical axis O and to be rotatable around the optical axis O. A distance scale ring 27 is fitted around the fixed outer cylinder 15 and the inner circumference of the focus ring 28 so as to be rotatable integrally with the focus ring 28. A distance scale (not shown) is printed on the outer peripheral surface of the distance scale ring 27. The distance scale is formed by a display window 29 fixed to the fixed outer cylinder 15 and an opening 15 a formed in the fixed outer cylinder 15. Observed through. A projection 17b projecting outward from the rear end of the decorative frame 17 is slidably fitted in a lead groove 27a formed on the inner peripheral surface of the distance scale ring 27.
[0011]
Accordingly, when the focus ring 28 rotates, the distance scale ring 27 rotates integrally with the focus ring 28, and the decorative frame 17 rotates integrally with the focus ring 28 while being movable along the optical axis O. Moves forward and backward along the optical axis O while rotating by the screw action of the male helicoid 17a and the female helicoid 20a. The focus adjustment is performed by moving the decorative frame 17 forward and backward. An AF inner peripheral gear (not shown) is formed on the inner peripheral surface of the distance scale ring 27, and an AF pinion connected to an AF motor meshes with the AF inner peripheral gear to perform the AF operation. The focus adjustment is performed by rotating the distance scale ring 27 by driving the AF motor.
[0012]
The first lens group L <b> 1 is fixed to a lens support frame 17 c protruding inward on the inner peripheral surface of the front end of the decorative plate 17. The second lens group L2 is fixed to the second lens group frame 18a, the fourth lens group L4 is fixed to the fourth lens group frame 18b, and the second lens group frame 18a and the fourth lens group frame 18b are moved in the first direction. It is fixed to the ring 18. The first moving ring 18 has an arm portion 18d protruding from the outer peripheral surface penetrates a straight guide elongated hole 14a (see FIG. 4) formed in the fixed cylinder 14 and has an inclined portion formed at the tip of the arm portion 18d. The protrusion 18e is slidably fitted in a lead groove 22d (see FIG. 3) formed on the inner peripheral surface of the zoom drive ring 22.
[0013]
The third lens group L3 is fixed to a third lens group support frame 19, and the third lens group support frame 19 is connected to the first movable ring 18 and a second movable ring 21 rotatably fitted around the first movable ring 18. Supported. On the outer peripheral surface of the third lens group support frame 19, as shown in a developed view in FIG. 8, three arm portions 19a protrude in the circumferential direction. The arm 19a penetrates the straight guide groove 18c (see FIG. 6) of the first moving ring 18, and an inclined projection 19b formed at the tip of the arm 19a is formed on the inner peripheral surface of the second moving ring 21. Slidably fitted in the three cam grooves 21a (see FIG. 7).
[0014]
The fixed cylinder 14 is formed with a rectilinear guide slot 14a through which an arm 18d formed in the first moving ring 18 penetrates, and the inner peripheral surface of the fixed cylinder 14 projects from the outer peripheral surface of the second moving ring 21. A cam groove 14b into which the tip of the provided projection 21b is slidably fitted is formed. At the front end of the fixed cylinder 14, three rectilinear guide members 23 are fixed in the circumferential direction. Each rectilinear guide member 23 has a guide projection 23a projecting outward. The guide projection 23a is formed in the helicoid ring 20 through a circumferential hole 22e formed in the zoom drive ring 22. Slidably fitted in the rectilinear guide groove 20e.
[0015]
Further, a pin 22a protrudes near the center of the outer peripheral surface of the zoom drive ring 22 fitted to the fixed cylinder 14, and the tip of the pin 22a is engaged with the focal length scale ring 26. A focal length scale (not shown) is printed on the outer peripheral surface of the focal length scale ring 26, and the focal length scale is observed through the display window 29 and the opening 15b formed in the fixed outer cylinder 15. The zoom drive ring 22 has a large diameter portion on the front end side (the first lens group L1 side), and has three pairs of front and rear guide protrusions 22b and 22c on the outer peripheral surface of the large diameter portion in the circumferential direction ( (See FIG. 3). The helicoid ring 20 is formed with three cam projections 20b having surface cams 20c and 20d of a predetermined shape in the front and rear direction in the circumferential direction. Each cam projection 20b is formed by a pair of corresponding guide projections 22b and 22c. They are slidably fitted between them. The contours of the surface cams 20c and 20d of the cam projection 20b are formed such that the combination of the female helicoid 17a and the male helicoid 20a with the lead corresponds to the movement locus of the first lens unit L1.
[0016]
Three cam grooves 22d are formed at equal intervals on the inner peripheral surface of the small-diameter portion of the zoom drive ring 22, and these cam grooves 22d are formed at the tips of the arms 18d of the first moving ring 18. The inclined projection 18e is slidably fitted. The contour of the cam groove 22d corresponds to the movement locus of the second lens unit L2 and the fourth lens unit L4.
[0017]
A zoom operation ring 25 is rotatably fitted around the outer periphery of the mount connecting ring 12 and the fixed outer cylinder 15, and a rubber ring 25a for preventing operation slip is fitted around the outer periphery of the zoom operation ring 25. . The zoom operation ring 25 can be moved to two positions, an electric zoom position moved forward (left side in FIG. 1) and a manual zoom position moved backward, and is moved to the electric zoom position in front. When the zoom operation ring 25 is provided, an inner peripheral teeth row-like portion 25b formed of a plurality of engaging teeth formed in the front end portion of the inner peripheral surface of the zoom operation ring 25 along the circumferential direction is provided in the zoom lens barrel 10. And is in a state where the electric zoom can be performed. In this state, the zoom operation ring 25 is located at the neutral position in the free state, zooming toward the telephoto side when manually rotating around the optical axis O, and zooming toward the wide-angle side when rotating the other side. Zooming is performed toward.
[0018]
When the zoom operation ring 25 is moved to the rear manual zoom position, the zoom operation ring 25 is formed along the circumferential direction at the rear end of the inner peripheral surface of the zoom operation ring 25 and extends in a direction parallel to the optical axis O. The circumferential tooth row portion (circumferential engaging portion) 25c meshes with the engaging tooth row portion (engaging portion) 31a of the zoom lever (lever member) 31 fixed to the zoom drive ring 22, and the zoom drive ring is rotated. 22. In this state, when the zoom operation ring 25 is manually rotated around the optical axis O, the zoom drive ring 22 is also rotated, whereby manual zooming is performed. In FIG. 1, illustration of various members related to the electric zoom (a zoom motor, a reduction gear train, a zoom code plate including an FPC, a brush that slides on the code plate, and the like) is omitted. FIG. 1 shows a state in which the zoom operation ring 25 is located at the rear manual zoom position.
[0019]
The zoom lever 31 has a base (inner end) 31 b fixed to the zoom drive ring 22 via a screw 32. The distal end (outer end) of the zoom lever 31 is engaged with the inner peripheral teeth 25c of the zoom operation ring 25 in a direction parallel to the optical axis O and extends in a direction parallel to the optical axis O. A tooth row portion 31a is formed. The engagement tooth row portion 31a includes four engagement teeth in this embodiment. When the zoom operation ring 25 is moved to the rear manual zoom position, the inner peripheral tooth row portion 25c meshes with the engagement tooth row portion 31a, and the zoom operation ring 25 is moved to the front electric zoom position. At this time, the engagement with the engagement tooth row portion 31a is released by separating from the engagement tooth row portion 31a.
[0020]
As shown in FIG. 10, each engaging tooth of the engaging tooth row portion 31a and the inner peripheral tooth row portion 25c has a tapered tip end facing in the meshing direction so as to easily mesh with each other. Have been. Further, one of the plurality (four) of the engaging teeth 31c constituting the engaging tooth row portion 31a is formed so that the inner peripheral tooth row is larger than the other engaging teeth so as to easily mesh with each other. It is formed so as to extend a predetermined length L in a direction (upward direction in FIG. 10) in which it meshes with the shape portion 25c. According to the configuration in which the engagement teeth 31c are provided, the zoom operation ring 25 is moved to the rear manual zoom position, and the inner peripheral teeth 25c are engaged with the engagement teeth 31a when the inner peripheral teeth 25c are engaged. Before the row portion 25c is securely engaged with the engagement tooth portion 31a, the extended tooth portion of the engagement tooth 31c is adjacent to the plurality of engagement teeth constituting the inner peripheral tooth row portion 25c. The engaging teeth 31a and the inner peripheral teeth 25c are inserted into any one of the pair of engaging teeth so that the inner peripheral teeth 25c are easily engaged with each other in the circumferential direction. Is reliably engaged with the engaging tooth row 31a, so that the inner peripheral tooth row 25c smoothly meshes with the engaging tooth row 31a. 9 shows a manual zoom state in which the inner peripheral teeth 25c are engaged with the engaging teeth 31a, and FIG. 10 shows the inner teeth from the engaging teeth 31a. The electric zoom state in which the unit 25c is separated is shown.
[0021]
A focal length scale ring 26 is rotatably fitted near the mount 11 inside the fixed outer cylinder 15, and the tip of the pin 22 a engages with the focal length scale ring 26. ing. When the zoom drive ring 22 rotates, the rotation is transmitted to the focal length scale ring 26 via the pin 22a, and the focal length scale ring 26 also rotates.
[0022]
The electric zoom lens barrel 10 having the above configuration and to which the present invention is applied operates as follows. When the photographer manually performs zooming, the zoom operation ring 25 is moved to the mount 11 side. Then, the inner peripheral tooth row portion 25c of the zoom operation ring 25 meshes with the engagement tooth row portion 31a of the zoom lever 31, whereby the zoom operation ring 25 and the zoom drive ring 22 are linked. When the zoom operation ring 25 is rotated from this state, the zoom drive ring 22 is also rotated via the zoom lever 31, and the fourth group lenses L 1, L 2, L 3, L 4 are moved from the first group with this rotation. Move and zoom.
[0023]
When the zoom drive ring 22 rotates around the optical axis O, the helicoid ring 20 guided straight by the relationship between the guide protrusion 23a and the straight guide groove 20e becomes a cam protrusion interposed between the guide protrusion 22b and the guide protrusion 22c. By the action of 20b, the surface cams 20c and 20d move straight along the optical axis O in accordance with the profile. Since the projection 17b is engaged with the lead groove 17a, the decorative frame 17 moves together with the helicoid ring 20 along the lead groove 17a. That is, the first lens group moves forward and backward along the optical axis O without rotating.
[0024]
The second lens group L2 and the fourth lens group L4 have a relationship in which the arm portion 18d is engaged with the straight guide elongated hole 14a of the fixed cylinder 14, and the inclined projection 18e is engaged with the cam groove 22d of the zoom drive ring 22. Move along the optical axis O without rotating. The third lens unit L3 moves along the optical axis O together with the first moving ring 18 (the second lens unit L2 and the fourth lens unit L4), and further, the arm 19a guides the first moving ring 18 straight. Since it is guided straight in the groove 18 c, it moves along the optical axis O relatively to the first moving ring 18.
[0025]
Here, when the first moving ring 18 moves along the optical axis O, the second moving ring 21 moves along the optical axis O integrally with the first moving ring 18. 14 and slide around the optical axis O. In the third lens group support frame 19, the arm 19 a passes through the straight guide groove 18 c of the first moving ring 18 and the inclined protrusion 19 b engages with the cam groove 21 a of the second moving ring 21. 21 moves along the optical axis O while rotating, and moves forward and backward along the optical axis O by the rotation of the second moving ring 21. That is, the third lens unit L3 relatively moves toward and away from the second lens unit L2 and the fourth lens unit L4.
[0026]
When the photographer performs electric zooming, he moves the zoom operation ring 25 forward. Then, the zoom operation ring 25 is disengaged from the zoom drive ring 22, and the inner peripheral toothed portion 25b is provided with a predetermined engaging toothed portion (not shown) provided in the zoom lens barrel 10. And the electronic zoom is enabled.
[0027]
As described above, according to the electric zoom lens barrel 10 to which the present invention is applied, the engagement that engages the focal length scale ring with the inner peripheral toothed portion formed along the inner peripheral surface of the zoom operation ring. A conventional configuration in which a toothed portion is provided is not adopted, and a zoom lever 31 configured as a non-annular member having one end fixed to the zoom drive ring 22 and an engaging toothed portion 31a at the other end is provided. Since the zoom operation ring 25 and the zoom drive ring 22 are interlocked via the intermediary, there is no need to form an engaging tooth row portion conventionally formed on the focal length scale ring. Can be configured.
[0028]
In the present embodiment, when the zoom operation ring 25 is moved to the manual zoom position, the inner toothed portion 25c of the zoom operation ring 25 meshes with the engagement toothed portion 31a of the zoom lever 31. However, the present invention is not limited to this, and each of the inner peripheral tooth row portion 25c and the engaging tooth row portion 31a may be configured as a spline that can mesh with each other. Also in this configuration, each spline has a tapered tip end facing in the meshing direction so as to be easily meshed with each other, and furthermore, a plurality of engaging members forming a spline corresponding to the engaging tooth row portion 31a. Some of the engagement teeth of the false tooth are formed to extend by a predetermined length in a direction in which they mesh with the splines corresponding to the inner peripheral dentition-like portion 25c more than the other teeth.
[0029]
Further, in the present embodiment, one of the four engagement teeth 31c constituting the engagement tooth row portion 31a meshes with the inner peripheral tooth row portion 25c more than the other three engagement teeth. It is configured to extend by a predetermined length L in the direction, but the present invention is not limited to this, and two of the plurality of engaging teeth forming the engaging It may be configured to extend by a predetermined length L in a direction meshing with the inner peripheral teeth row-like portion 25c more than the other two engaging teeth. Further, the number of the plurality of engaging teeth forming the engaging tooth row portion 31a is not limited to four in the present embodiment, and may be another number.
[0030]
Further, in the present embodiment, the electric zoom lens barrel 10 has been described as the electric zoom lens barrel, but the present invention is not limited to this, and it is operable to move along the optical axis direction and to rotate around the optical axis. The zoom operation ring has a special zoom operation ring, and switches between manual zooming and electric zooming at one and the other moving positions in the optical axis direction of the zoom operation ring, and according to the amount of rotation from the neutral position of the zoom operation ring during the electric zooming. The present invention can be applied to other electric zoom lens barrels as long as the zooming speed is changed by an electric zoom lens barrel.
[0031]
【The invention's effect】
As described above, according to the electric zoom lens barrel of the present invention, when the zoom operation ring is moved to the manual zooming position, the inner end is fixed to the zoom drive ring, and the lever is configured as a non-annular member. Since the zoom operation ring and the zoom drive ring are connected via a member, there is no need to provide an engaging tooth row portion on a rotating annular member such as a focal length scale ring. The power zoom lens barrel can be reduced in size because it can be made thin.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an upper half from an optical axis of an electric zoom lens barrel to which the present invention is applied.
FIG. 2 is a development view of a helicoid ring.
FIG. 3 is a development view of a zoom drive ring.
FIG. 4 is a development view of a fixed ring.
FIG. 5 is a front view showing a linear guide member fixed to the fixed ring shown in FIG.
FIG. 6 is a development view of a first moving ring.
FIG. 7 is a development view of a second moving ring.
FIG. 8 is a development view of a third lens group support frame.
FIG. 9 is an enlarged front view showing a main part of the present invention.
FIG. 10 is a view of a main part of the same figure viewed from another angle.
[Explanation of symbols]
Reference Signs List 10 Motorized zoom lens barrel 12 Mount ring 13 Housing 15 Fixed outer cylinder 22 Zoom drive ring 25 Zoom operation ring 25c Inner circumference toothed portion (circumferential engagement portion)
26 focal length scale ring 27 distance scale ring 29 display window 31 zoom lever (lever member)
31a Engaging tooth row part (engaging part)

Claims (4)

A zoom drive ring rotatable about the optical axis;
A zoom mechanism for changing the focal length by moving the photographing lens group back and forth along the optical axis direction by forward and reverse rotation of the zoom drive ring;
A zoom operation ring capable of a linear movement operation in the optical axis direction and a rotation operation around the optical axis;
A circumferential engaging portion formed on the zoom operation ring along the circumferential direction;
A lever member made of a non-circular member, an inner end portion of which is fixed to the zoom driving ring, and an outer end portion having an engaging portion which engages with and disengages from a circumferential engaging portion of the zoom operation ring;
At one of the moving positions of the zoom operation ring in the optical axis direction, a manual operation for engaging the circumferential engagement portion and the engagement portion of the lever member to integrate the zoom operation ring and the zoom drive ring in the circumferential direction. A zoom mechanism;
At the other movement position in the optical axis direction of the zoom operation ring, the engagement between the circumferential engagement portion and the engagement portion of the lever member is released, and the electric zoom mechanism connects the zoom mechanism to an electric drive system. When;
An electric zoom lens barrel comprising: The zoom lens according to claim 1, further comprising: a focal length scale ring connected to the zoom drive ring and integrally rotating with the zoom drive ring around the optical axis;
The lever member is an electric zoom lens barrel provided separately from the focal length scale ring. 3. The zoom operation ring according to claim 1, wherein the circumferential engagement portion of the zoom operation ring and the engagement portion of the lever member include a plurality of engagement teeth extending in a direction parallel to the optical axis. The electric zoom lens barrel that is disengaged by 4. The electric zoom lens barrel according to claim 3, wherein a part of the plurality of engaging teeth of the lever member protrudes more toward the engaging teeth of the zoom operation ring than other engaging teeth. 5.

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