JP3340178B2 - Zoom lens device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens device used for a variable focal length camera.

[0002]

2. Description of the Related Art Generally, a zoom lens used in a camera has a plurality of lens groups, and at least two of the plurality of lens groups are moved in an optical axis direction to change a focal length. It is configured to be. In this case, the movement of these lens groups along the optical axis direction uses a cam cylinder that rotates around the optical axis as shown in, for example, JP-A-48-57645. The lens group is driven along the optical axis direction.

[0003] However, the cam cylinder has a complicated shape, which increases the manufacturing cost. In addition, since the cam cylinder is rotated about the optical axis, it is difficult to draw out a flexible substrate as a conductive material from the lens. In addition, the cam barrel
Since it relates to the entire lens barrel, restrictions are placed on the arrangement and configuration of each component, making it difficult to reduce the overall size.

[0004]

As described above, when a cam barrel is used as a means for moving a lens group, the manufacturing cost increases, and it is difficult to pull out the flexible substrate from the lens, and the overall size is reduced. Is difficult.

An object of the present invention is to move a lens group without using expensive parts such as a cam barrel, so that there is no restriction on the arrangement of each part, and the whole can be reduced in size at low cost. To provide a zoom lens device.

[0006]

SUMMARY OF THE INVENTION The present invention provides a zoom lens which comprises a plurality of lens groups, and performs a zooming and focusing operation for changing a focal length by moving at least two lens groups in an optical axis direction. An apparatus, comprising: a driving mechanism for moving one of the at least two lens groups along the optical axis direction; a motor for driving the driving mechanism; and a driving mechanism provided on the one of the lens groups. Is rotated in a direction and an angle corresponding to the moving direction and the moving amount with a direction intersecting the optical axis direction as a rotation axis ,
And, a zoom range that engages with the other lens group side and changes an interval between the one lens group and the other lens group to an interval corresponding to the focal length with the rotation,
A cam in which a focusing range in which a distance between the one lens group and the other lens group is not changed regardless of the rotation is set in a step-like manner.

[0007]

According to the present invention, the zoom range and the focusing range are
One of the at least two lens groups is driven by a motor using a cam in which
Is moved in the optical axis direction by a drive mechanism,
The cam provided on one of the lens groups is rotated in a direction and an angle corresponding to the moving direction and the moving amount, and by engagement of this cam with the other lens group , the cam is rotated in the zoom range. with it, the distance between one lens group and the other lens groups, by changing to a predetermined distance corresponding to the focal length, off
In the focusing range, regardless of the cam rotation,
Change the distance between the lens group and the other lens group.
Instead, perform a focusing operation .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the zoom lens device according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the zoom lens device comprises:
It is configured on the front surface of the camera body 11, and has a plurality of lens groups, a front lens group 12 as one lens group, and a rear lens group 13 as the other lens group. The front lens group 12 is supported by a shutter 14, the rear lens group 13 is supported by a rear lens frame 15, and the front lens group 12 and the rear lens group 13 extend along the optical axis 16. It is arranged back and forth.

The shutter 14 is fixed to the inner periphery of the front end of a cylindrical moving frame 18, and the moving frame 18 is integrally provided in a lens barrel 19. It is configured to be movable along the axis 16. In addition, the lens barrel
An outer peripheral surface of 19 is formed on an inner surface of a front end portion of a lens barrel 22 integrated with a lens barrel base 21 fixed to a front portion of the camera body 11 by screws 20.
The lens barrel packing 23 and the lens barrel packing receiver 24 holding the lens barrel packing 23 are in contact with each other, and are slidably supported by the lens frame 22 along the optical axis 16. A stopper 21c is provided behind the lens barrel base 21 when the rear lens frame 15 retreats.

On the other hand, a rear lens group 13 supported by a rear lens frame 15 is configured to be movable along an optical axis 16 in a cylindrical moving frame 18, and a rear surface of the rear lens group 13 is provided. Is
It faces the opening 11a of the camera body 11. One end of a rear ball guide shaft 26 is integrally embedded in the front surface of the rear ball frame 15. The rear ball guide shaft 26 is provided along the optical axis 16 and is slidably fitted in a guide hole 27 provided in the shutter 14 along the direction of the optical axis 16 so that the rear ball frame 15 and the rear The ball lens group 13 is guided so as to be able to advance and retreat along the optical axis 16 direction. Further, a repulsion spring 28 is provided between the rear surface of the shutter 14 and the rear lens frame 15 so as to act to push and expand the space between the shutter 14 and the rear lens frame 15.

A part of the moving frame 18 extends outward from the rear end of the lens barrel 19 to form an extension 18A. The extension 18A has a guide hole 29 and a female screw guide. Screw part 30
Is formed. Then, the guide hole 29 is slidably fitted with the moving guide shaft 31 provided in parallel with the optical axis 16,
The guide screw portion 30 is screwed with a moving screw 32 also provided in parallel with the optical axis 16. Further, a drive mechanism 33 is constituted by the moving guide shaft 31 and the moving screw 32, and as shown in FIG. As described above, both ends are supported by fitting them into the support holes 22a and 22b of the lens frame 22 and the support holes 21a and 21b of the lens barrel base 21, respectively.

A moving screw gear 34 is integrally attached to the right end of the moving screw 32. This moving screw gear 34 is connected to a motor 35 via a reduction gear train 36 as shown in FIG. The motor 35 is activated by an operation signal output from the electric control circuit 37 due to a magnification change operation or the like by a photographer. Further, the rotation amount of the motor 35 is detected by a rotation detecting device 38, and the electric control circuit 37
Inputs a rotation amount from the rotation detection device 38, and outputs a stop control signal for the motor 35 when the rotation amount reaches a predetermined value.

As shown in FIG. 1, a boss 40 is integrally formed on the rear upper surface of the moving frame 18.
A cam 41 with a gear is rotatably fitted to the outer periphery of the bracket, and is attached by a retaining screw 42. Also this cam 41
Has a cam portion 41a formed at a lower portion and a circular gear portion 41b integrally formed at an upper portion. The gear 41b of the cam 41 meshes with a rack 43a of a rack plate 43 parallel to the optical axis 16, as shown in FIG. The right end of the rack plate 43 is fixed to the lens barrel base 21 with screws 44 as shown in FIG. Therefore, when the moving frame 18 moves along the optical axis 16 as described later, the cam 41
The gear 41b of the cam 41 and the rack 43a of the rack plate 43 are driven to rotate by meshing with each other.

A rear ball guide roller 46 is attached to the upper surface of the rear frame 15 so as to be rotatable in a vertical state by screws 47, and is formed on the upper surface of the moving frame 18 as shown in FIG. It protrudes from the upper surface of the moving frame 18 through an elongated hole 48 along the optical axis 16. The outer peripheral surface of the rear ball guide roller 46 is opposed to the cam portion 41a of the cam 41 in a contactable state.

In FIG. 1, reference numeral 50 denotes a front cover of the camera, and the front cover 50 of the camera is integrally attached to the front surface of the camera body 11 at a predetermined distance.
In FIG. 1, the moving frame 18 and the lens barrel 19 integrated with the moving frame 18 are retracted, and the rear end of the rear lens frame 15 is
At the rear end position in contact with the stopper portion 21c. At this rear end position, most of the lens barrel 19 is located in the front cover 50 of the camera as shown,
This is a so-called collapsed state.

Next, the operation of the above embodiment will be described.

First, when the photographer turns on the main switch of the camera (not shown), the electric control circuit shown in FIG.
37 operates to start the motor 35, and rotationally drives the moving screw 32 of the driving mechanism 33 via the reduction gear train 36 and the moving screw gear 34 shown in FIG. With the rotation of the moving screw 32, a moving frame provided with the guide screw portion 30 screwed with the moving screw 32
18 is guided by the movement guide shaft 31 and linearly moves forward along the optical axis 16.

As the moving frame 18 moves, the moving frame 18
The lens barrel 19, the shutter 14, the front lens group 12, and the cam 41, which are integrated therewith, also move to the left. The cam 41 rotates counterclockwise in FIG. 2 as the gear 41b of the cam 41 meshes with the rack 43a of the rack plate 43 as it moves to the left.

At this time, the rear lens frame 15 and the rear lens group 13
Receives a rightward pressure by the repulsion spring 28, but does not move because the rear end of the rear lens frame 15 is in contact with the stopper portion 21c.

In this state, when the rotation of the motor 35 continues and reaches the wide-angle position shown in FIG. 3, the electric control circuit 37 shown in FIG.
It is determined that the motor 35 has rotated until it reaches the wide-angle position, and the motor 35 is controlled to stop. At this time, the cam 41 is engaged with the outer periphery of the rear lens guide roller 46 by the movement of the cam 41 itself to the left and the counterclockwise rotation accompanying this movement, as shown in FIG. The interval between the group 13 and the front lens group 12 is set to a predetermined interval corresponding to the focal length at the wide-angle position.

As described above, when the photographer turns on the main switch, first, the lens is extended from the retracted state to the wide-angle position where photographing is possible.

Next, when the photographer operates a zoom button switch (not shown) to the telephoto side, the motor 35 rotates again,
The front lens group 12 moves to the left. At this time, the cam 41
Similarly to the above-mentioned case, while rotating counterclockwise while moving to the left, the rear lens group 13
Is brought closer to the front lens group 12 against the repulsion force of the repulsion spring 28. When the motor reaches a standard position (not shown), the motor
35 stops and is positioned at the standard position. Of course, the distance between the front lens group 12 and the rear lens group 13 is a predetermined distance corresponding to the standard position by the action of the cam 41.

When the zoom button switch is further operated toward the telephoto side from the standard position, the motor 35 rotates and the telephoto position shown in FIGS. 5 and 6 is obtained by the same operation as described above. Also in this case, the distance between the front lens group 12 and the rear lens group 13 is a predetermined distance corresponding to the telephoto position by the operation of the cam 41.

The operations from the telephoto position to the standard position, the wide-angle position, and the retracted state are performed from the retracted state to the wide-angle position,
The reverse operation is performed to the standard position and the telephoto position.

As described above, the cam 41 rotates counterclockwise or clockwise at a predetermined angle in the direction corresponding to the moving direction and the moving amount of the front lens group 12, and the cam 41 rotates. Engage with the rear lens guide roller 46 provided on the side, and change the distance between the front lens group 12 and the rear lens group 13 to the distance corresponding to the focal length with the rotation.

When a release button switch (not shown) is operated in each of the above-described wide-angle position, standard position, and telephoto position, the stop position of each wide-angle position, standard position, and telephoto position is determined based on data from a focus detection device (not shown). Then, the motor 35 rotates by an amount necessary for focusing, and the front lens group 12 is moved along the optical axis 16. At this time, the cam 41 also moves, and the cam portion 41a is rotated by the engagement between the gear portion 41b of the cam 41 and the rack portion 43a of the rack plate 43, but as shown in the development view of the cam portion 41a in FIG. In each of the wide-angle position, the standard position, and the telephoto position, the focusing range is set in a step-like manner. The distance from the lens group 13 does not change, and only the focusing operation is performed.

That is, in this focusing range,
As shown in FIG. 8, since the cam height of the cam portion 41a with respect to the rear ball guide roller 46 is set to be constant, the rear ball guide roller 46 follows the movement of the cam 41 along the optical axis 16 direction. However, even if the cam portion 41a rotates, the rear ball guide roller
The relative position of 46 with respect to the center of the cam 41 does not change, and therefore, as described above, the front lens group 12 and the rear lens group
The distance from 13 does not change.

When the focusing operation is completed in this way, the shutter 14 operates to complete the photographing. After the photographing is completed, the motor 35 rotates in the reverse direction, and the front lens group 12 and the rear lens group 13 return to the predetermined stop positions at the wide-angle position, the standard position, and the telephoto position, and wait for the next photographing.

According to the above-described configuration, the driving of the front lens group 12 and the rear lens group 13 is difficult to machine such as a cam cylinder, and the guide screw portion 30 and the moving screw 32 are used without using a component having a high manufacturing cost. And the combination of the plate-shaped cam 41 and the rear ball guide roller 46,
The structure is simplified and the manufacturing cost is reduced. Further, the cam 41 does not relate to the entire lens barrel like the cam barrel, and can be formed in a small size, so that the overall size can be reduced.

Furthermore, since the cam 41 is formed in one place, the flexible substrate can be easily arranged on the shutter 14 and the like, and the degree of freedom in arranging parts such as the shutter 14 and the moving guide shaft 31 is improved. I do.

In the above embodiment, since the zoom and the focus are operated by the common motor 35, the cam portion 41a needs to be formed in a step-like shape as shown in FIG. 8 in order to obtain a focusing range. . For this reason, wide-angle, standard,
Although a three-stage step zoom including telephoto or the like has been described, it is needless to say that the number of steps of the step zoom may be increased by increasing the number of focusing ranges .

A repulsion spring 28 is provided between the shutter 14 of the front lens group 12 and the rear frame 15 of the rear lens group 13.
If the position of the cam 41 and the position of the rear ball guide roller 46 are reversed, a tension spring may be used, and furthermore, it may be provided between the rear ball frame 15 and the camera body 11. Also, the cam portion 41a of the cam 41
If these are grooved, these springs can be omitted.

[0034]

According to the zoom lens device of the present invention,'s
When the camera range and focusing range are set in steps
Using beam, among the lens groups, either lens group is moved in the optical axis direction by a drive mechanism driven by a motor, the moving direction and moving amount of the cam provided on one lens group side Rotate in the corresponding direction and angle, and by engaging this cam with the other lens group side,
In the zoom range, the distance between one lens group and the other lens group is changed to a predetermined distance corresponding to the focal length in accordance with the rotation of the cam.
Irrespective of the one lens group and the other lens
The focusing operation can be performed without changing the distance between the groups.
Accordingly, without using expensive parts of the cam barrel, etc., Ki out be the zoom and focusing operation by moving the lens group, further
In addition, operate the zoom and focus with a common motor
And the placement of each part is not restricted.
It is possible to lower the cost of the structure is simplified, it can be made compact overall.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a retracted state of an embodiment of a zoom lens apparatus according to the present invention.

FIG. 2 is a plan view showing a cam portion of the same.

FIG. 3 is a sectional view showing a wide-angle position of the zoom lens device shown in FIG. 1;

FIG. 4 is a plan view showing the same cam portion.

FIG. 5 is a sectional view showing a telephoto position of the zoom lens device shown in FIG. 1;

FIG. 6 is a plan view showing the same cam portion.

FIG. 7 is a sectional view taken along the line III-III of FIG. 3;

FIG. 8 is a development view of the cam shown in FIG. 1;

FIG. 9 is a block diagram showing an electric circuit according to the embodiment.

[Explanation of symbols]

12 Front lens group as one lens group 13 Rear lens group as the other lens group 16 Optical axis 33 Drive mechanism 35 Motor 41 Cam

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-72594 (JP, A) JP-A-4-277732 (JP, A) JP-A-1-167711 (JP, A) 223803 (JP, A) JP-A-6-67077 (JP, A) JP-A-64-18116 (JP, A) JP-A 64-20513 (JP, A) JP-A-5-34557 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B ⁷ /02-7/105

Claims (1)

(57) [Claims] 1. A zoom lens device comprising a plurality of lens groups, wherein at least two lens groups are moved in an optical axis direction to perform a zoom and focusing operation for changing a focal length, wherein A driving mechanism for moving one of the lens groups along the optical axis direction; a motor for driving the driving mechanism; and a motor provided on the one lens group side, intersecting the optical axis direction.
The first lens group and the other lens group are rotated with a direction as a rotation axis in a direction and an angle corresponding to the moving direction and the moving amount, and are engaged with the other lens group side, and are rotated with the rotation. A cam in which a zoom range in which the interval of the lens is changed to an interval corresponding to the focal length, and a focusing range in which the interval of the one lens group and the other lens group do not change regardless of the rotation are set in a stepwise manner. A zoom lens device comprising: