JPH0625813B2 - Operating mechanism of auto focus zoom lens barrel - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating mechanism of an autofocus zoom lens barrel, and more specifically, a focusing operation of a zoom lens barrel mainly used for an autofocus type camera, The present invention relates to an operation mechanism of a zooming operation and a focus limiter mechanism.

[Prior Art] In general, an auto-focus type camera is provided with a motor that drives a photographing lens group arranged in a lens barrel forward and backward in the optical axis direction, and controls the rotation of the motor according to a distance to a subject. Focusing is automatically performed by doing. However, there is a demand to manually perform the focusing operation depending on the usage situation. Therefore, as a solution, a manual operation ring connected to the shooting lens group is installed side by side with the lens barrel, and by rotating the operation ring, the shooting lens group is moved back and forth in the optical axis direction, and focusing is performed manually. I was able to do it. Further, in the case of the zoom lens barrel, a zooming operation ring for performing zooming operation is provided separately from this, and zooming is performed by the zooming operation ring.

By the way, in such an operating mechanism, since the manual operation ring for focusing is always connected to the taking lens, the manual operation ring for focusing also rotates at the same time when the autofocus is activated. Therefore, if the operating ring is touched by a hand at this time, a large load is applied to the motor, the connecting member in the middle, and the like, which causes a failure or a malfunction. Therefore, the applicant of the present application has already selected one of the zoom mechanism that moves the zoom lens group forward and backward in the optical axis direction, the focus mechanism that moves the focus lens group forward and backward in the optical axis direction, and either one of the zoom mechanism or the focus mechanism. An operation mechanism for a zoom lens barrel is proposed, which includes an operation ring that engages and moves one of the zoom lens group and the focus lens group back and forth. (Japanese Patent Application Sho 62
According to the operation mechanism of the zoom lens barrel, when the operation ring is engaged with the focus mechanism, focusing is performed by operating the operation ring. When the operation ring is switched and engaged with the zoom mechanism, zooming is performed. At this time, since the operation ring and the focus mechanism are not engaged,
Even if the focus mechanism is driven by a motor for autofocus, the motion is not transmitted to the operation ring. For this reason, a large load is not applied to the motor, and the operating ring does not rotate during autofocusing, so that the operating ring can be placed at a position most convenient for operation, which is easy to touch.

[Problems to be Solved by the Invention] In a super-telephoto lens, a super-telephoto zoom lens, a macro lens, etc., the amount of movement of the image plane is large, and therefore it takes time to perform focusing by autofocus. Therefore, such a lens may be provided with a focus limiter mechanism.

This focus limiter mechanism limits the operating range of the focus mechanism in advance. For example, when operating the autofocus, the distance to the subject is predicted in advance, and the focus mechanism is limited to the range of the predicted distance. This is to enable the operation and shorten the moving range of the focus lens group to shorten the focusing operation time.

Such a focus limiter mechanism is used exclusively when activating the auto focus, and is not necessary when manually performing focusing. Therefore, when the focus limiter mechanism is activated, the operation ring and the focus mechanism must be disengaged from each other, so that the operation is performed twice, and the operation is complicated. there were.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the conventional drawbacks described above and to provide an operation mechanism for an autofocus zoom lens barrel having a focus limiter mechanism that is easy.

[Means for solving problems]

In order to solve the above-mentioned problems, an operation mechanism of an autofocus zoom lens barrel according to the present invention includes a zoom mechanism for moving a zoom lens group forward and backward in the optical axis direction, and a focus mechanism for moving a focus lens group forward and backward in the optical axis direction. And, by moving forward and backward in the optical axis direction, selectively engages with either one of the zoom mechanism or the focus mechanism and rotates around the optical axis so that the one in the engaged state of the two mechanisms is selected. An operating ring that drives and moves one of the zoom lens group and the focus lens group back and forth, and enters the moving area of the focus mechanism by rotating from a predetermined non-operating position around the optical axis to operate the focus mechanism. A focus limiter mechanism that limits the
When the focus limiter mechanism is in the non-operating position, it does not interfere with the engagement between the operation ring and the focus mechanism,
When the focus limiter mechanism is rotated to a position that limits the operating range of the focus mechanism, an operation ring drive mechanism that releases the engagement between the operation ring and the focus mechanism in conjunction therewith is provided. Characterize.

[Operation] When the focus limiter operation ring in the manual state is operated to activate the focus limiter mechanism, the operation ring is disengaged from the focus mechanism by the operation ring drive mechanism, and therefore the operation ring is operated even if the autofocus is activated. The operation is not transmitted to the ring. Therefore, when the focus limiter mechanism is actuated, the operation ring is forcibly disengaged even if the operation ring is not accidentally removed from the focus mechanism.

[Embodiment] An embodiment of the operating mechanism of the autofocus zoom lens barrel according to the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of the present invention, and the illustration of the lower half is omitted.

In the figure, 1 is an inner body of the lens barrel, 2 is an outer body fixed to the outer side thereof, and a front cover 3 and a rear cover 4 are fixed to the outermost surface thereof. 5 is a bayonet claw fixed to the rear end of the lens barrel and engaged with a mount of the camera body;
Is a diaphragm ring for adjusting the aperture area of an aperture diaphragm (not shown).

Fixed lens groups 7 and 8 are fixed to the front end and the rear side of the inner body 1. Along the way, a zoom lens group 9 composed of a front group 9a and a rear group 9b, and a focus lens group 10 are fixed to lens frames 11a, 11b, 12 which are arranged to be movable back and forth in the optical axis direction. ing. Each of the lens frames 11a, 11b, 12 has a pin 13
a, 13b, and 14 are provided in a protruding manner, and the pins penetrate through the long holes 15a, 15b, 16 formed in the inner body 1 in the optical axis direction. A zooming cam cylinder 17 and a focusing cam cylinder 18 are rotatably fitted to the outer periphery of the inner body 1, and the cams 19a, 19b and 20 formed on the cam cylinders 17 and 18 have the above-mentioned pins. 13a,
13b and 14 are engaged with each other. Therefore, when the zoom cam cylinder 17 rotates, the zoom lens groups 9a and 9b move back and forth in the optical axis direction to perform zooming.
When the focusing cam barrel 18 rotates, the focus lens group 10 moves back and forth in the optical axis direction for focusing.

A zoom operation cylinder 21 and a focus operation cylinder 22 are rotatably arranged on the outer periphery of the outer main body 2. A head of a screw 24 standing on the cam barrel 17 is engaged with a groove 23 formed on the inner surface of the zoom barrel 21, and the cam barrel 17 and the zoom barrel 21 are connected via the screw 24. Rotate together.
25 is a groove formed in the outer body 2 in the circumferential direction,
The screw 24 penetrates therethrough. Focus operating tube 2
Reference numeral 2 is integrally connected to the focusing cam barrel 18 via a coupling barrel 40 by means of a screw (not shown), and the focus actuating barrel 22 and the cam barrel 18 rotate integrally. As described above, the zooming cam barrel 17 and the zoom actuating barrel 21 constitute a zoom mechanism, and the focusing cam barrel 18 and the focusing actuating barrel 22 constitute a focus mechanism. Further, an internal gear 26 is formed on the inner peripheral side of the focus operating cylinder 22,
A gear (not shown) driven by the autofocus motor meshes with the internal gear 26, and the focus operating cylinder 22 is rotationally driven by the autofocus motor.

An operation ring 27 is rotatably attached to the outer periphery of the central portion of the outer body 2. The operation ring 27 is also arranged so as to be able to move back and forth in the optical axis direction. In the vicinity of the center of the lower surface of the operation ring 27, a pair of V-shaped parallel grooves 28 are formed in the circumferential direction, and a click ball 30 pressed by a coil spring 29 from the outer main body 2 side is arranged. The operation ring 27 is engaged with either one of the parallel grooves 28, and the operating ring 27 is clicked at any position to determine the axial position. FIG. 1 shows a state in which the operation ring 27 is on the tip side (on the left side in the figure).

Holes 31 and 32 are formed near the left and right ends of the operation ring 27, and steel balls 33 and 34 are fitted into the holes 31 and 32. The steel balls 33, 34 are equally divided in the circumference and are arranged on the left and right sides of the operation ring 27, for example, six each, and are pushed inward by a ring-shaped leaf spring 35 provided on the outside thereof.

The focus actuating cylinder 22 has a large number of grooves 36, which are engaged with the steel balls 33 when the operating ring 27 is on the left side as shown in FIG. FIG. 2 shows a state in which the steel ball 33 is engaged with the groove 36. Since the groove 36 is continuously formed on the circumference, the operation ring 27 is rotated to be in any position. Even, steel ball 33
And the groove 36 can engage. Further, the zoom actuating cylinder 21 is also formed with a groove 37 exactly the same so that the steel ball 34 is engaged when the operation ring 27 is on the rear side (right side).

Therefore, in the mechanism of the present embodiment, when manually operating the focusing, it is possible to freely switch between the manual focusing and the zooming by moving the operation ring 27 back and forth.

Reference numerals 38 and 39 denote the front cover 3 and the rear cover so that the distance scale displayed on the outer periphery of the focus operating cylinder 22 or the zoom scale displayed on the outer periphery of the zoom operating cylinder 21 can be seen from the outside. 4 is a transparent window.

In this embodiment, the focus limiter mechanism operates from the near point to ∞
The operation of the focus mechanism that operates up to a near distance from a near point to a predetermined distance or from a predetermined distance to ∞, and when the focus limiter mechanism is not activated, the focus mechanism can be freely operated from the near point to ∞. I am trying. In this embodiment, as shown in FIG. 7, the focus limiter mechanism has a focus operating barrel 22.
A stopper plate 55 is provided on the outer side of the rear cover 3 as shown in FIGS. 8 to 10.
Both stopper pieces 57 of the focus mechanism configured to be movable between a near-point side stopper piece 57a and an ∞-side stopper piece 57b which are erected at the tip of the stopper mechanism.
The limiting lever 52 is arranged between a and 57b so that the position can be adjusted.

That is, as shown in FIG. 8, the limit lever 52 moves the near-point side stopper piece 5 within the movable range of the stopper plate 55.
7a and the infinity stopper piece 57b (when the limiting lever 52 is in this position in FIG. 7), the stopper plate 55 causes the stopper pieces 57a,
It can move freely between 7b (indicated by arrow A in FIG. 8).

Further, as shown in FIG. 9, when the limiting lever 52 is stopped between the stopper pieces 57a and 57b and the stopper plate 55 is positioned between the near-point side stopper piece 57a and the limiting lever 52. The focusing mechanism can perform the focusing operation only for a predetermined distance from the near point determined by the position of the limiting lever 52 (indicated by an arrow B in FIG. 9). Similarly, as shown in FIG. 10, when the stopper plate 55 is located between the ∞-side stopper piece 57b and the limiting lever 52, focusing can be performed from a predetermined position to ∞ (indicated by an arrow C in FIG. 10). Shown).

In this example, as shown in FIG. 1, the limiting lever 52 is fixed inside the focus limiter operating ring 50 rotatably fitted to the outside of the rear cover 3, and the focus limiter operating ring 50 is fixed. By rotating, the position of the limiting lever 52 can be set to a desired position. Further, as shown in FIGS. 3 and 5, the focus limiter operation ring 50 includes an operation ring 2
Thrust ring 5 to prevent 7 from moving in the optical axis direction
1 and a lock nut 56 for fixing the focus limiter operating ring 50 to the front cover 3 at a desired rotation position. Furthermore, this focus limiter operating ring 5
At the position where 0, the focus limiter does not work,
A click ball 70 urged by a coil spring 71 provided on the front cover 3 is fitted therein, and a hole 72 is provided for stopping the position of the focus limiter operation ring 50 by clicking.

Therefore, according to this focus limiter mechanism, by rotating the focus limiter operating ring 50 and operating the lock nut 56, the limiting lever 52 can be fixed at an arbitrary position between the two stopper plates 57a and 57b. Therefore, the focus limiter can be continuously adjusted to any position between the near point and ∞. Further, when the focus limiter is not activated, the focus limiter operation ring 50 can be stopped by clicking.

Further, in the present embodiment, when the focus limiter mechanism is operated, if the above-mentioned operation ring 27 is engaged with the focus mechanism side, an operation ring drive mechanism is provided for releasing this engagement.

As shown in FIGS. 4 and 6, this operation ring drive mechanism is provided below the thrust ring 51 along the optical axis, and is configured to move the operation ring 27 and the slit 61 in which a slant surface 62 that extends rearward is formed. It is composed of a restriction pin 53 for restricting. As shown in FIG. 6, the limiting pin 53 is fitted in the slide groove 54 so as to be movable in the optical axis direction, but at a position where the focus limiter operating ring 50 is clicked and stopped (the focus limiter is activated). Position)
Only when it becomes (as shown in FIG. 5), it becomes possible to enter the slit 61 of the thrust ring 51,
The operation ring 27 is provided at a position where it can move forward and can be engaged with the focus mechanism. In other cases, as shown in FIGS. 3 and 4, the restricting pin 53 is prohibited from moving forward by the thrust ring 51. In this state, the operating ring 27 moves forward. It does not engage the focus mechanism. 63 is a guide.

Further, the state in which the above-described restriction pin 53 enters the slit 61 (a manual operation state in which the focus limiter does not operate)
When the focus limiter operation ring 50 is rotated to operate the focus limiter mechanism, the limiting pin 53 is guided by the slant surface 62 of the slide groove and moves rearward, so that the operation ring 27 becomes the focus mechanism. Even when engaged, the operation ring 27 is pushed backward by the limiting pin 53, and the engagement between the operation ring 27 and the focus mechanism is released.

In the above embodiment, the focus limiter mechanism has a structure in which the limit lever is fixed to an arbitrary position between the two stopper plates with the lock nut, but the focus limiter mechanism may have another structure.

Further, in the above-mentioned embodiment, the operating ring drive mechanism is constituted by the slit provided on the thrust ring and the limiting pin. However, this may release the engagement between the operating ring and the focus mechanism when the focus limiter is activated. However, another mechanism may be used.

[Effect of the Invention] As described above, according to the operation mechanism of the autofocus zoom lens barrel according to the present invention, the operation of releasing the engagement between the operation ring and the focus mechanism in conjunction with the operation of the focus limiter mechanism. Since the ring drive mechanism is provided, when the focus limiter is activated, the operation ring is automatically disengaged from the focus mechanism, and the operation ring can be brought into the auto-focus state with a single operation without operating the operation ring again. Is extremely simple, and has an excellent effect that the operating ring does not accidentally enter the manual focusing operation state while the focus limiter is operating.

[Brief description of drawings]

FIG. 1 is a side sectional view of a lower half portion of an embodiment of the present invention, which is not shown, FIG. 2 is an enlarged plan view of a steel ball and a groove portion thereof, and FIG. 3 is an embodiment of a focus limiter operating state. FIG. 4 is an enlarged side sectional view, FIG. 4 is a partial plan view thereof, FIG. 5 is an enlarged side sectional view of an embodiment in a focus limiter released state, FIG. 6 is a partial plan view thereof, and FIG. 7 shows a focus limiter mechanism thereof. Front sectional views, FIGS. 8 to 10 are developed views showing the relationship between the focus limiter mechanism and the operating ring drive mechanism. 1 ... Inner body, 2 ... Outer body, 9a, 9b ... Zoom lens group, 10 ... Focus lens group, 13a, 1
3b ... Pin, 14 ... Pin, 17 ... Zooming cam barrel, 18 ... Focusing cam barrel, 19a, 19
b ... Cam, 20 ... Cam, 21 ... Zoom actuating cylinder, 2
2 ... Focus operating cylinder, 23 ... Groove, 24 ... Screw,
27 ... Operation ring, 29 ... Parallel groove, 30 ... Click ball, 31, 32 ... Hole, 33, 34 ... Steel ball, 35 ...
... leaf spring, 36, 37 ... groove, 50 ... focus limiter operating ring, 51 ... thrust ring, 52 ... limit lever, 53 ... limit pin, 54 ... slide groove, 55 ...
... Stopper plate, 56 ... Lock nut, 57a, 57b
...... Stopper piece, 61 ...... Slit, 62 ...... Slope, 7
0 ... click ball.

Claims (1)

[Claims] 1. A zoom mechanism for moving a zoom lens group forward and backward in the optical axis direction, a focus mechanism for moving a focus lens group forward and backward in the optical axis direction, and either the zoom mechanism or the focus mechanism by moving forward and backward in the optical axis direction. An operating ring that selectively engages with one of them and drives one of the two mechanisms that is in an engaged state by rotating about the optical axis to advance or retract one of the zoom lens group or the focus lens group. , A focus limiter mechanism that limits the operating range of the focus mechanism by entering the moving area of the focus mechanism by rotating from a predetermined non-operating position around the optical axis, and the focus limiter mechanism is in the non-operating position. In this case, the focus limiter mechanism does not interfere with the engagement between the operating ring and the focus mechanism. An autofocus zoom lens, comprising: an operating ring drive mechanism for releasing the engagement between the operating ring and the focus mechanism in conjunction with rotation of the operating ring to a position that limits the operating range of the frame. The operating mechanism of the lens barrel.