JP2521864Y2 - Lens moving device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a lens moving device such as a zoom lens for moving a plurality of lens groups relative to each other in the optical axis direction to perform magnification or focus. is there.

[Conventional technology]

Conventionally, the most common lens moving device of this type is configured such that a plurality of cam grooves are formed in a cylindrical cam frame, and a plurality of lens groups are relatively positioned by the cam grooves. Was.

On the other hand, as another conventional example, as disclosed in Japanese Patent Publication No. 56-15487, a focusing ring having a focusing lens and a zoom lens moving member for moving the zoom lens in the optical axis direction, The gear transmission mechanism includes a gear transmission mechanism interposed between the focusing ring and the zoom lens moving member for interlocking the two, and a frictional engagement member interposed in the middle of the gear transmission mechanism. The zoom lens can be moved to the wide side in the case of a zoom phenomenon of subject enlargement caused by moving the lens in the optical axis direction, and the zoom lens is moved to the tele side in the case of a zoom phenomenon of subject reduction. In each case, the movement of the zoom lens at the time of each zoom phenomenon is set so as to eliminate the zoom phenomenon caused by the movement of the focus lens. Rectangular when moving the zoom lens moving member the frictional engagement member is Zurippu, there is a lens moving device sliding surface imaging machine, characterized by being configured so as not to transmit the driving force to the focus ring side.

Further, as another conventional example, as disclosed in Japanese Utility Model Publication No. 48-24729, an elongate cam frame is provided rotatably in parallel with the optical axis of the lens system, and fitted into the variator barrel. By providing a cam groove that fits and a cam groove that fits into the convention sweater barrel, during zooming, the variator lens barrel is directly advanced and retracted to rotate the cam frame interlockingly. There is a zooming operation mechanism of a zoom lens configured to move forward and backward in conjunction.

Further, as still another conventional example, as disclosed in Japanese Utility Model Publication No. 63-47865, a first photographing optical unit, a second photographing optical unit, and the second photographing optical unit are held. ,
A shaft member that forms a rotation axis for changing the focal length by moving the second photographing optical unit into and out of the photographing optical path; and the first member when the second photographing optical unit is out of the photographing optical path. First adjusting means for adjusting the reference focus by displacing the photographing optical means in the photographing optical axis direction, and displacing the shaft member in the axial direction while the second photographing optical means is in the photographing optical path. Then, the second imaging optical unit is displaced in the optical axis direction to adjust the reference focus.
There is provided a variable focal length device for a camera, comprising:

[Problems to be solved by the invention]

However, in the case of the conventional cylindrical cam frame in which the cam groove is formed, it is very troublesome to form a cam groove having a shape accurately corresponding to the amount of movement of the lens group, and the processing cost is high. Eliminating rush is almost impossible.

Further, in the lens moving device disclosed in Japanese Patent Publication No. 56-15487, a cylindrical or plate-shaped zoom lens moving member having a cam groove is used to move the zoom lens in the optical axis direction. Therefore, not only has the same problem as the above conventional example, but also to move the focusing lens,
Since a plurality of gear transmission mechanisms including a transmission shaft, a spur gear, and / or a worm / worm gear, and having a large number of parts are arranged around the lens barrel, space efficiency is poor, which hinders downsizing. It is a factor.

Further, in the zooming operation mechanism of the zoom lens disclosed in Japanese Utility Model Publication No. 48-24729, the cam groove must be formed on the outer periphery of the elongated cam rod, and the cam groove is formed on the cylindrical cam frame described above. It is more difficult to process the cam groove than in the case of forming, especially when the cam groove is formed in the same portion in the axial direction of the cam rod, there is a possibility that the movement of the lens frame may not be performed smoothly, In addition, since a cam rod, a slider engaging with the cam groove, and the like are interposed in the movement range of the lens, there is a problem that a lot of space is required.

Furthermore, the variable focal length device of the camera disclosed in the above-mentioned Japanese Utility Model Publication No. 63-47865 is a bifocal type, so that the focal length can be changed by moving the first photographing optical means in the optical axis direction. And the second photographing optical means is moved forward and backward on the photographing optical axis, and the means for moving the two photographing optical means is not specified (that is, it is merely disclosed as an arbitrary means). However, even if it is presumed that this is driven by a lead screw, it only moves straight, and cannot be applied to a zoom lens moving means including a movement having an inflection point.

The present invention has been made in view of the above circumstances, and its purpose is to reduce the cost with a small number of components, to be space-efficient, compact, and to have a lens with an inflection point. It is an object of the present invention to provide a lens moving device capable of smoothly and accurately moving a group.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a lens moving device that relatively moves a plurality of lens groups in the optical axis direction to perform zooming or focusing, and is rotatable with a bias toward the inner wall side of the fixed lens barrel. A first feed screw, which is disposed so as to be movable in the optical axis direction, has a gear and a contact, and is spring-biased on the side where the contact is provided; An arbitrary first lens group of the plurality of lens groups attached via a lens frame to a first moving frame screwed into the first movable frame; And a second feed screw having a gear, which is immovable in the optical axis direction, and the plurality of second feed screws attached via a lens frame to a second moving frame screwed to the second feed screw. Any of the second lens groups, the first moving frame and the upper A guide rod that guides the movement of the second moving frame in the optical axis direction; and a gear that is substantially annular and is rotatably supported on the inner peripheral portion of the fixed barrel and provided on the inner or outer periphery. A drive ring in which the gears of the first and second feed screws mesh with each other, a first motor meshing with the gear of the drive ring to rotate the drive ring, and a gear formed at least in part and having the end face A cam surface formed with a contact surface at the tip of the first feed screw and rotatably supported on the inner peripheral portion of the fixed lens barrel; And a second motor that is driven to rotate by rotating the first and second feed screws via a drive ring by the rotation of the first motor to move the first and second lens groups in the optical axis direction. Perform linear displacement movement relative to At the same time, the cam member is decelerated and rotated by the rotation of the second motor, the first feed screw is moved in the direction of the optical axis by the cam surface, and the first lens group is combined with the linear displacement movement and changed. It is configured to bend and move.

[Action]

When the first motor is rotationally driven by, for example, a zooming operation, the lens moving device configured as described above rotates the drive ring with the rotational torque, and rotates the first and second feed screws via gears. . The first lens group and the second lens group screwed to the respective feed screws
The lens group is relatively linearly displaced and moved in the optical axis direction, and at the same time, the rotation of the second motor causes the cam member to be decelerated and rotated, so that the contact member pressed against the cam surface is pressed and rotated. By moving the first feed screw in the direction of the optical axis, the first lens group can be combined with the linear displacement movement to perform the inflection displacement movement.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side sectional view showing a lens moving device according to the present invention taking a zoom lens as an example, and FIG. 2 is a sectional view of FIG.
FIG. 9 is a partially cutaway sectional view taken along line XX. In both figures,
Reference numeral 1 denotes a lens barrel cover integrated with a camera body (not shown), and a fixed lens barrel 2 is further provided in the cover 1. The fixed lens barrel 2 includes a lens barrel mounting frame 2a, a lens barrel ring 2b, and a guide ring 4 having an opening at the center, and these members are fixed by screws 3, respectively. Above lens barrel ring 2b
Has a flange portion 2c at the end on the image surface side, that is, on the film surface side (right side portion). A first feed screw 5 is provided between the flange portion 2c and the guide ring 4 on the distal end side of the fixed lens barrel 2. The lens barrel ring 2b is supported so as to be rotatable toward the inner wall side and to be slidable in the optical axis direction. This first feed screw 5 is
At one end (right end in FIG. 1), a gear 6 and a contact 7 at its end face are provided, and a coil spring 9 applying a pressure expansion elastic force between the guide ring 4 and the stop ring 8 moves to the film surface side. Spring biased. Reference numeral 10 denotes a stopper for preventing the first feed screw 5 from coming off.

Thus, the front group moving frame 11 is screwed into the first feed screw 5 as a first moving frame, and the front group moving frame 11 is arbitrarily selected from the plurality of lens groups via the lens frame 12. A front lens group 13 as one lens group is supported.

On the other hand, a second feed screw 14 is rotatably supported between the guide ring 4 and the flange portion 2c substantially opposite to the first feed screw 5. The second feed screw 14 has a gear 15 at the film surface side end and a washer 16 at the subject side end so as to be immovable in the optical axis direction. A rear group moving frame 17 as a second moving frame is screwed into the second feed screw 14.
A rear lens group 19 as an arbitrary second lens group among a plurality of lens groups is supported via a lens frame 18.

Also, a flange portion of the guide ring 4 and the lens barrel ring 2b.
As is clear from FIG. 2, two pairs of guide rods 20a and 20b are supported at different angles between 2c, and the front group moving frame 11 is inserted into one of the guide rods 20a. The rear group moving frame 17 is inserted through the guide rod 20b to prevent the rotation of the moving frames 11, 17 and guide the movement in the optical axis direction.

Further, on the inner peripheral surface of the lens barrel mounting frame 2a of the fixed lens barrel 2,
An annular drive ring 21 is rotatably mounted,
The gears 6 and 15 of the first and second feed screws 5 and 14 mesh with an internal gear 22 provided on the inner peripheral surface of the drive ring 21. Output shaft
The output gear 24 provided for 23a is engaged.

Further, the drive ring 21 is provided on the inner peripheral surface of the lens barrel mounting frame 2a.
Separately, a disc-shaped cam member 25 is rotatably supported,
As shown in FIG. 3, a second motor is connected to an internal gear 26 formed on substantially the half of the inner peripheral surface of the cam member 25 via a reduction gear 27.
The output gear 29 provided on the output shaft 28a of the gear 28 meshes.

The contact 7 at the distal end of the first feed screw 5 is in pressure contact with the cam surface 30 formed on the other half of the cam member 25. As shown in FIG. 4, the thickness of the cam surface 30 in this example is reduced in the form of a slope in the forward rotation direction (clockwise direction in FIG. 3).

Next, the operation of the zoom lens as the lens moving device of the present invention will be described.

In conjunction with the zooming operation of the camera, first, when the first motor 23 is driven to rotate, the drive ring 21 meshing with the output gear 24 is rotated.
The first and second feed screws 5 and 14 are rotated at predetermined speeds via the gears 6 and 15 meshing with the internal gear 22. As a result, the front group lens group 13 and the rear group lens group 19 are illuminated via the front group moving frame 11 and the rear group moving frame 17 screwed to the first feed screw 5 and the second feed screw 14, respectively. It relatively linearly moves in the axial direction.

On the other hand, in conjunction with the first motor 23, the second motor 28
, And the rotation torque is transmitted from the output gear 29 to the internal gear 26 via the reduction gear 27 to rotate the cam member 25 at a reduced speed. For this reason, the first feed screw 5 pressed against the cam surface 30 of the cam member 25 via the contact 7 is
As the thickness of the cam surface 22 increases, for example, with the rotation of 25, the cam surface 22 is pushed toward the subject while rotating against the spring force of the coil spring 9. Therefore, only the front lens group 13 is further moved toward the subject in combination with the linear displacement movement.

That is, the movement of the front group lens group 13 and the rear group lens group 19 will be described here. In the zooming operation from wide to tele, the movement of the rear group lens group 19 as the variator lens is controlled by the second feed screw 14. In contrast to the linear displacement movement caused by the rotation, the movement of the front lens group 13 is a so-called variable movement in which the linear displacement movement caused by the rotation of the first feed screw 5 and the movement of the first feed screw 5 by the cam surface 30 are combined. It enables a bending displacement movement and can operate as a compensator lens.

The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention.

For example, the first lead screw 5 and the second lead screw 14
Has been described with respect to an example in which each is used, but a plurality of each may be used.

Further, the guide rods 20a and 20b for guiding the movement of the front lens group 13 and the rear lens group 19 are not limited to two, but are finished to an accuracy such that the two lens groups 13 and 19 can move smoothly. As long as it is one each.

Further, the fixed lens barrel 2 is composed of the three members of the lens barrel mounting frame 2a, the lens barrel ring 2b, and the guide ring 4, but these members may be integrally formed by one member.

Further, the driving force of the second motor 28 for rotating the cam member 25 is transmitted via the reduction gear 27, but the rotation of the motor with a reduction gear may be transmitted directly to the cam member 25.

Also, the lens moving device of the present invention has been described as an example applied to a zoom lens, but it is needless to say that a lens moving device other than a zoom lens, for example, a lens retracting and retracting operation in a retractable camera or a focusing lens group. It can be widely applied to, for example, focusing operation.

[Effect of the invention]

As described above, according to the lens moving apparatus of the present invention, the compensator lens as a compensator lens for zooming and focusing is realized by the combined operation of the screw drive by the feed screw and the cam drive by the cam for the feed screw. The inflection displacement movement of one lens group can be performed reliably and smoothly. Also, in the combined operation of the feed screw and the cam, the end of the first feed screw for performing the inflection displacement movement is constantly pressed against the cam surface of the cam member by the spring urging force. There is no backlash during zooming as in the case of the ring cam system. Further, since the motor for driving the first and second feed screws and the motor for driving the cam member are separately provided, the inflection displacement movement of the front lens group with respect to the linear displacement movement of the front and rear lens groups is provided. Timing can be adjusted. Furthermore, there is no need to form a complicated cam groove which is difficult to process as compared with the conventional ring cam system, so that the number of parts is small, the occupied space is small, and it can be manufactured at low cost.
There is also an effect that the size and weight of the camera can be reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of a lens moving device according to an embodiment of the present invention. FIG. 2 is a sectional view showing a section taken along line XX of FIG. The figure is a rear view showing the relationship between the cam member and its related members, and FIG.
FIG. 4 is an explanatory diagram showing a cross section taken along line YY of FIG. 3 in an expanded manner. 1 ... lens barrel cover, 2 ... fixed lens barrel, 2a ... lens barrel mounting frame, 2b ... lens barrel ring, 2c ... flange part, 4 ... guide ring, 5 ... first feed screw, 6,15 ... gear, 7 ...
Contact element, 9: Coil spring, 11: Front group moving frame, 12, 18
... Lens frame, 13 front lens group, 14 second feed screw, 17 rear group moving frame, 19 rear group lens group, 20a, 20
b guide rod, 21 drive ring, 22, 26 internal gear, 23 first motor, 25 cam member, 27 reduction gear, 28 second motor, 30 ...... Cam surface.

Claims (1)

(57) [Scope of request for utility model registration] 1. A lens moving apparatus for performing magnification or focusing by relatively moving a plurality of lens groups in an optical axis direction, wherein said lens moving apparatus is biased toward an inner wall of a fixed lens barrel and rotatable in the optical axis direction. And has gears and contacts,
A first feed screw spring-biased to the side where the contact is provided, and the plurality of first feed screws attached via a lens frame to a first moving frame screwed to the first feed screw. And a second feed screw having a gear, which is disposed so as to be rotatable biased toward the inner wall of the fixed lens barrel and immovable in the optical axis direction. An arbitrary second lens group of the plurality of lens groups attached via a lens frame to a second moving frame screwed to the second feed screw; and the first moving frame. A guide rod for guiding the movement of the second moving frame in the optical axis direction; and a gear having a substantially annular shape and rotatably supported by the inner peripheral portion of the fixed lens barrel and provided on the inner or outer periphery. A drive ring in which the gears of the first and second feed screws are respectively meshed; A first motor that meshes with a gear of the first ring and drives the drive ring to rotate; a gear is formed on at least a part of the first motor; A cam member rotatably supported on the inner peripheral portion of the fixed lens barrel; and a second motor for rotating the cam member via its gears and reduction gears. By rotating the first and second feed screws via the driving ring to relatively linearly move the first and second lens groups in the optical axis direction, the rotation of the second motor The cam member is rotated at a reduced speed, the first feed screw is moved in the optical axis direction by the cam surface, and the first lens group is combined with the linear displacement movement to perform an inflection displacement movement. Characteristic lens movement Location.