JPS63237019A - Manually operating mechanism for autofocusing lens - Google Patents

Abstract

PURPOSE:To obtain stable focusing regardless of the directions of a camera at the time of manual focusing by providing a brake which adds resistance to the forward and backward movements of a focusing lens group at the time of a manual operation. CONSTITUTION:A brake pad 58 is lowered and pressed to the outside peripheral face of a focus actuating cylinder 22 and the resistance is held added to the rotating movement of the cylinder 22 in the state in which the manual focusing is possible. The resistance is, therefore, added to the advance and retreat of the focusing lens group 10 in a photographing lens and the downward movement of the focusing lens group 10 by its own weight does not arise when the camera is held to face upward or downward even in the state in which an operating ring 27 is held interlocked to a zoom mechanism and the focusing mechanism is freed. The always stable focusing is thereby obtd. regardless of the directions of the camera even if photographing is carried out by directing the camera upward or downward.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an autofocus camera lens that automatically focuses by motor drive.
In particular, the present invention relates to a manual operation mechanism that allows switching between focusing and zooming using a single manual operation ring.

[Conventional Technique] Autofocus camera lenses are generally equipped with a motor that drives the focus lens group placed inside the lens barrel forward and backward in the direction of its optical axis, and the rotation of the motor is adjusted according to the distance to the subject. Focusing is performed automatically by controlling the However, depending on the usage situation, there is a demand for manual focusing operation. As a solution to this problem, we installed a manual operation ring connected to the focus lens group in the lens cavity, and by rotating the operation ring, the focus lens group can be moved forward and backward in the direction of its tip axis, allowing manual focusing. It is known that it is possible to do this.

[Problems to be Solved by the Invention] In an autofocus camera lens, the mechanical parts that operate the focusing are made to operate extremely lightly so as not to apply an unreasonable load to the motor. Therefore, in the case of a lens that uses a single operation ring to switch between zooming and focusing, when the operation ring is linked to the zoom mechanism, the focusing mechanism becomes free and the camera can be held facing downward or upward. If you try to take a picture with the focus lens group moving under its own weight, you will lose focus.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a manual operation mechanism for an autofocus lens that can eliminate such conventional drawbacks and obtain stable focusing regardless of the orientation of the camera during manual focusing.

[Means for Solving the Problems] In order to solve the above-mentioned problems, a manual operation mechanism for an autofocus lens according to the present invention includes a zoom mechanism that moves the zoom lens group forward and backward in the optical axis direction, and a zoom mechanism that moves the zoom lens group back and forth in the optical axis direction. An autofocus lens comprising a focus mechanism that moves forward and backward in the optical axis direction, and a manual operation ring that selectively engages with either the zoom mechanism or the focus mechanism to move one of the zoom lens group or focus lens group back and forth. The present invention is characterized in that a brake is provided to add resistance to the movement of the focus lens group back and forth during manual operation.

[Function] When manual focusing is performed, the brake adds resistance to the movement of the focus lens group, and the focus lens group does not descend under its own weight.

Since the brake is not applied during autofocus, focusing can be performed with light force and no excessive load is applied to the motor.

[Embodiment] FIG. 1 is a cross-sectional view of one embodiment of the present invention, and 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 outside 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 the plant of the camera body; 6;
is an aperture ring that reduces the aperture area of the aperture stop, which is not shown.

Inside the inner body l, there are fixed lens groups 7 on the front and rear sides.
．． 8 is fixed. In the middle, a zoom lens group 9 consisting of a front group 9a and a rear group 9b, and a focus lens group 10 are fixed to lens frames 11a, 11b, and 12, respectively, which are arranged to move forward and backward in the optical axis direction. ing. These lens frames 11a, llb, 12 each have a bottle 13a,
13b and 14 are provided in a protruding manner, and these bottles pass through long holes 15a, 15b, and 16 formed long in the optical axis direction in the inner body l. A zooming cam cylinder 17 and a focusing cam cylinder 18 are rotatably fitted on the outer periphery of the inner main body 1, and a cam 19a is formed in each of the cam cylinders 17 and 18.

The bins 13a, 13b, 14 are engaged with the bins 19b, 20, respectively. Therefore, by rotating the zooming cam tube 17, the zoom lens groups 9a and 9b advance and retreat in the optical axis direction to perform zooming, and by rotating the focusing cam tube 18, the focus lens group 10
Focusing is performed by moving back and forth in the optical axis direction.

A zoom operation barrel 21 and a focus operation barrel 22 are rotatably arranged on the outer periphery of the outer main body 2. The head of a screw 24 installed upright on the cam n17 is engaged with a groove 23 formed on the inner surface of the zoom cylinder 21, and the cam cylinder 17 and the zoom cylinder 21 are integrally connected via the screw 24. Rotate to.

25 is.

This is a groove formed in the outer body 2 in the circumferential direction, and the screw 24
passes through it. The focus operation cylinder 22 is integrally connected to the focusing cam cylinder 18 via a connecting cylinder 40 by a screw (not shown), and the focus operation cylinder 22 and the cam cylinder 18 rotate together. In this way, the zooming cam cylinder 17 and the zoom operation ring 2
1 constitutes a zoom mechanism, and a focusing cam tube 18, a focus operation tube 22, etc. constitute a focus mechanism. Also, the focus operation cylinder 22
An internal gear 26 is formed on the inner circumferential side of the cylinder 2. A gear (not shown) driven by an autofocus motor meshes with the internal gear 26, and the focus operation cylinder 2
2 is rotationally driven by an autofocus motor.

An operating ring 27 is rotatably attached to the outer periphery of the central portion of the outer body 2. This operation ring 27 is arranged so as to be freely advanced and retracted in the optical axis direction as well. A pair of parallel grooves 28 separated by a V-shaped partition are formed in the circumferential direction near the center of the lower surface of the operating ring 27, and a click pawl 30 pushed by a coil spring 29 from the outer body 2 side is inserted into the circumferential direction. The operating ring 27 is engaged with either one of the parallel grooves 28 and clicked at one of the positions, thereby determining the axial position. FIG. 1 shows a state in which the operating fii 27 is on the tip side (on the left side in the figure), and FIG. 3 shows a state in which the operating ring 27 is on the rear side (on the right side in the figure).

Holes 31, 32 are bored near both left and right ends of the operating ring 27, and steel balls 33, 34 are fitted into the holes 31, 32. These steel balls 33 and 34 are divided into equal parts around the circumference and the operation ring 27 is
For example, six of them are arranged on each side of the left and right sides, and are pushed inward by a ring-shaped leaf spring 35 provided on the outside.

A large number of grooves 36 are continuously formed on the outer circumferential surface of the focus operation cylinder 22, with which the steel balls 33 engage when the operation 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 this groove 36.
Since the groove 36 is formed continuously around the circumference, the operating ring 2
No matter what position 7 is rotated to, the steel ball 33 and the groove 36 can engage with each other. In addition, the zoom operation barrel 2
1 is also formed with a groove 37 similar to the above, so that the steel ball 34 engages when the operating ring 27 is on the rear side (right side) as shown in FIG.

38 and 39 are the front cover 3 and the rear cover so that the distance scale displayed on the outer periphery of the focus operation barrel 22 or the zoom scale displayed on the outer periphery of the zoom operation barrel 21 can be seen from the outside. This is a transparent window installed in 4.

FIG. 4 shows a cross section taken along the line IV-rV in FIG.

A protrusion 41 is fixedly protruding from the outer periphery of the focus operation barrel 22, and this protrusion 41 rotates together with the focus operation barrel 22. In addition, a fixed stopper 42 for infinity and a fixed stopper 43 for close-up are fixed to the fixed wall 3a protruding inward of the front cover 3, and when the focus operation cylinder 22 rotates, the protruding 41 comes into contact with this re-fixing stopper 42 and 43, and the focus operation cylinder 22 is held in between.
can be rotated.

Between the refixing stoppers 42 and 43, a plurality of (three on the nut layer side) movable stoppers 44 are spaced apart from each other.
, 45 and 46 are rotatably attached to the fixed wall 3a. These movable stoppers are each biased in the rotational direction by springs 47, and are connected to holes 48 in the front cover 3.
A movable stopper is always pressed against the pole 49 fitted into the pole 49.... In addition, the pole 51 fitted into the hole 50 of the front cover 3 is shifted from the position of the leaf spring 5.
It is energized outward at 2, and by further shifting the position, 2
Between the two fixed stoppers 42 and 43, a rotating piece 55 is biased clockwise by a spring 56 and is rotatably attached to the fixed wall 3a. This rotating piece 55 is always pressed against the pole 54 fitted into the hole 53 of the front cover. The rotary piece 55 has a drawing 57 that protrudes rearward and abuts the front end of the operating ring 27 as shown in FIG.
, the focus actuating cylinder 22 protrudes inward and is pressed against the outer periphery of the focus actuating cylinder 22 as shown in FIG.
A brake pad 58 is fixedly provided to provide resistance to the rotation of 2.

A switching ring 59 is rotatably attached to the outer periphery of the front cover 3. Each pole 49 is provided on the inner peripheral surface of this switching ring 59.
..., 51, 54 are engaged with, and five grooves 60 are formed at successive distances from the pole.

Reference numerals 61 and 62 each have a leaf spring whose base end is fixed to the distal cover 3 and whose distal end is bent at a substantially right angle, and 63 is a groove in which the distal end of one of the leaf springs engages (a groove on both plates). (springs 81, 62 do not engage at the same time), 64 is a push button that releases the engagement state.

FIG. 4 shows that the pole 54 pushed by the rotating piece 55 is connected to the switching ring 5.
9 is shown engaged in the groove 60 of No. 9. In this state, the rotating piece 55 has rotated clockwise by the amount that the pawl 54 has entered into the groove 60. Therefore, 6 pieces 5
7 goes slightly upward, and as shown in Figure 1, 6 pieces 5
7 and the operating ring 27 do not come into contact with each other, and the operating ring 27 can freely move forward and backward. As shown in FIG. 1, when the operating ring 27 is set forward (to the left in the figure), the operating ring 27 is engaged with the focus operating barrel 22 via the steel ball 33 and the groove 36. . Therefore, by rotating the operating ring 27, the focus lens group lO moves forward and backward in the optical axis direction, allowing manual focusing. At this time, the operating ring 27 and the zoom operating ring 2
1, the zoom mechanism does not operate.

Furthermore, when the operation ring 27 is moved backward (to the right in the figure) as shown in FIG. 3, the steel ball 34 engages with the groove 37 of the zoom operation barrel 21, so the operation g: 127 is rotated. As a result, the zoom lens groups 9a and 9b move forward and backward in the optical axis direction,
Zooming is performed. At this time, the operating ring 2
7 and the focus operation tube 22 are separated,
Even if the focus mechanism is operated by the autofocus motor, the movement is not transmitted to the operating ring 27.

Further, in the state shown in FIG. 4, that is, in a state where manual focusing is possible, the brake butt 58 descends and is pressed against the outer circumferential surface of the focus actuation tube 22, adding resistance to the retracting movement of the focus actuation tube 22. . Therefore, resistance is added to the movement of the focus lens group 10 in the photographic lens, and even when the operation ring 27 is linked to the zoom mechanism and the focusing mechanism is free, it is difficult to move the camera upward or downward. In this case, the focus lens group 10 is prevented from falling due to its own weight.

When the switching ring 59 is rotated clockwise (autofocus state) from the state shown in FIG. 4 (manual operation state), the pole 54
Although the engagement between the groove 60 and the plate spring 62 is released, the leaf spring 62 is disengaged from the groove 63.
, and the switching ring 59 cannot be rotated further clockwise (although it can be returned counterclockwise); however, if the push button 64 is pressed at this point, the engagement is released. , the switching ring 59 can be rotated clockwise. Note that when the switching ring 59, which has been rotated clockwise to enter the autofocus state, is rotated counterclockwise to return to the manual operation state, the plate spring 61 is at the position where it engages with the groove 63. It can no longer be rotated counterclockwise (although it can be rotated back clockwise), and
If the push button 64 is pressed here, the bond is released.

The switching ring 59 can be rotated counterclockwise. In this way, the pushbutton 64 separates the manual operation state and the autofocus state.

While pressing the push button 64 from the state shown in FIG.
When rotated clockwise, the pawl 51 pushed by the leaf spring 52 then engages with the groove 60. At the same time, an autofocus switch (not shown) is turned on. In the subsequent state, the rotating piece 55 is pushed by the pole 54 and rotates a little counterclockwise as shown in FIG. 5, and the six pieces 57 move down a little as shown in FIG. The front end of the operating ring 27 comes into contact with the six pieces 57 in this way. Therefore, in the autofocus state, engagement between the operation ring 27 and the focus mechanism is prevented, and the six pieces 57 constitute engagement prevention means. Further, the brake pad 58 moves upward a little and separates from the circumferential surface of the focus actuation cylinder 22, and the resistance applied to the focus actuation cylinder 22 is released. In this state (not shown) in which the pawl 51 is engaged with the groove 60, the movable stoppers 44, 45, 46 do not come into contact with the protrusion 41, as in FIG. Therefore, the protrusion 41 can fully move between the fixed stops 43, 42, and autofocus operates in a range from close distance (for example, 3.5 mm) to infinity.

Next, when the switching ring 59 is further rotated clockwise,
As shown in FIG. 5, the pole 49 that is in contact with the left movable stopper 44 engages with the groove 60, and the movable stopper 44 is engaged with the groove 60.
-/Pal 4 rotates slightly counterclockwise. Then, the movable stopper 45 comes into contact with the protrusion 41, and the protrusion 41 moves between the 67-movement stopper 44 and the fixed stopper 42, and the autofocus operating range increases, for example, to 4.
It is regulated between 5Il and infinity.

When the switching ring 59 is further rotated clockwise.

The movable stopper 45 at the center comes into contact with the protrusion 41, and the autofocus operating range is restricted to a range from 611 to infinity, for example.

When the switching ring 59 is further rotated clockwise, the movable stopper 46 on the right side comes into contact with the protrusion 41, and the autofocus operating range is restricted to, for example, from 10 cm to infinity.

Note that the number and position of the movable stoppers can be set arbitrarily depending on the type of lens, etc., and the operating range of focusing does not necessarily have to include infinity, but may vary depending on the purpose of use of the lens, etc. The range can be set as appropriate.

[Effects of the Invention] According to the manual operation mechanism for an autofocus lens of the present invention, during manual focusing operation, resistance is added to the forward and backward movement of the focus lens group, so that the focus lens group does not descend due to its own weight. , has the excellent effect of being able to always obtain stable focus regardless of the orientation, even when shooting with the camera facing upward or downward.

[Brief explanation of the drawing]

Fig. 1 is a side cross-sectional view of the lower half of an embodiment of the present invention, with illustration omitted, Fig. 2 is an enlarged plan view of the steel ball and groove portion, and Fig. 3 shows the state in which the operating ring is moved. 4 is a sectional view taken along line 17-IT in FIG. 1, and FIG. 5 is a sectional view taken along line 17-IT in FIG.
It is a sectional view taken along the V line. l...Inner body, 2...Outer body, 9a, 9b...
・Zoom lens group, 10... Focus lens group, 1
3a, 13b...Bin, 14...Bin, 17...
Cam tube for zooming, 18... Cam tube for focusing, 19a, 19b... Cam, 20... Cam, 21
...Zoom operation barrel, 22...Focus operation barrel, 2
3... Groove, 2゛ 4... Screw, 27... Operating ring,
29...Parallel groove, 30...Click pole, 31.
32... Hole, 33.34... Steel ball, 35... Leaf spring, 36, 37... Groove, 41... Protrusion, 42.4
3...Fixed stopper, 44, 45.46...Movable stopper, 49, 51.54...Pole, 55...Rotating piece, 57...6 piece, 58...Brake butt.

Claims (1)

[Claims] a zoom mechanism that moves the zoom lens group forward and backward in the optical axis direction;
A focus mechanism that moves the focus lens group forward and backward in the optical axis direction, and a manual operation ring that selectively engages with either the zoom mechanism or the focus mechanism and moves one of the zoom lens group or the focus lens group back and forth. 1. A manual operation mechanism for an autofocus lens, characterized in that the autofocus lens is provided with a brake that adds resistance to the forward and backward movement of a focus lens group during manual operation.