JP2003227988A - Zoom lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact zoom lens barrel which can be completely collapsed without making the entire length of a cam barrel long even in the case of zoom lens in which the mutual moving amount of a lens group is large. <P>SOLUTION: In the zoom lens barrel holding the zoom lens to perform variable power by changing at least a distance between a 1st lens group and a 2nd lens group, the lens group whose moving distance from a reference position is simply increased/decreased in accordance with magnification change between a telephoto end and a wide angle end out of the 1st lens group and the 2nd lens group is guided by a 1st guiding member having a cam groove in a specified variable power area and guided by a 2nd guiding member different from the 1st guiding member in the other variable power areas. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel used in a camera.

[0002]

2. Description of the Related Art In recent years, in a compact camera, when not in use, the lens barrel is retracted near the image forming surface (hereinafter referred to as "collapsed") to prevent the lens barrel from protruding from the camera body, thereby improving portability. Cameras have become popular.

In recent digital cameras,
There is a camera provided with a zoom lens having three lens groups, in which the first lens group and the second lens group are moved during zooming, and the third lens group is moved during focusing. Although the cam barrel having the cam groove is rotated to move the first lens group and the second lens group, the first lens group and the second lens group are separated from each other at the wide angle,
There are many configurations that approach when telephoto.

[0004]

As described above, when using the zoom lens having a structure in which the first lens group and the second lens group are separated from each other at a wide angle and approached at a telephoto position, the first lens group and the second lens group are used. A cam barrel having a cam groove corresponding to a change in relative distance from the group is required, but the length of the cam barrel is a limitation when retracting the zoom lens.

That is, when the amount of movement of each lens group is large, the total length of the cam barrel becomes long, which causes an obstacle to collapse. Further, when a zoom lens in which the amount of movement of each lens group is simply used is used, the power of each lens group becomes strong, the error sensitivity becomes sensitive, and the productivity deteriorates.

A technique aiming at solving such a problem is disclosed in Japanese Patent Laid-Open No. 3-180823. In this publication, two cam barrels are used to shorten the total length of the cam barrels. There is. However, if two cam barrels are used, the lens barrel becomes thicker in the radial direction and the cost becomes higher.

The present invention has been made in view of the above problems, and is a compact lens that can be fully retracted without forming the entire length of the cam barrel even in a zoom lens in which the amount of movement of the lens groups is large. It is an object of the invention to propose a simple zoom lens barrel.

[0008]

The above object can be achieved by any of the following means.

In the zoom lens barrel holding a zoom lens for performing zooming by changing the distance between at least the first lens group and the second lens group,
Of the lens group and the second lens group, the lens group in which the movement distance from the reference position simply increases or decreases between the telephoto end and the wide-angle end in accordance with the change in magnification, has a cam groove in a predetermined zoom region. The zoom lens barrel is characterized in that it is guided by one guide member and is guided by a second guide member different from the first guide member in the other zooming regions.

In a zoom lens barrel capable of holding a zoom lens for zooming by changing the distance between a plurality of lens groups and retracting the same, a cam barrel having a plurality of cam grooves, and the cam barrel A driving member which is guided by the cam groove and moves in the optical axis direction, and a lens barrel which holds a predetermined lens group and is regulated to be able to approach and separate from the driving member within a predetermined range, An urging member for urging the lens barrel and the driving member in a direction of separating the lens barrel from each other, and when the lens barrel is retracted, the lens barrel and the driving member move to the vicinity of the image forming surface, Approaches the driving member against the urging force of the urging member, and in a predetermined magnification changing region, the lens barrel is driven by the driving member to cause the urging force of the urging member to move to the driving member. The farthest away from The zoom lens barrel according to claim.

A cam barrel having a plurality of cam grooves, wherein the zoom lens barrel holds a zoom lens for zooming by changing the distance between the plurality of lens groups, and the cam barrel has a plurality of cam grooves. A driving member which is guided by the cam groove and moves in the optical axis direction, and a lens barrel which holds a predetermined lens group and is regulated to be able to approach and separate from the driving member within a predetermined range, An urging member for urging the lens barrel and the driving member in a direction of separating the lens barrel from each other, and when the lens barrel is retracted, the driving member and the lens barrel move to the vicinity of the image forming surface, and the lens barrel Approaches the drive member against the urging force of the urging member, and in the variable magnification region near the wide-angle end, the lens barrel is driven by the drive member and is driven by the urging force of the urging member. Most separated from the member A zoom lens mirror characterized in that, in a variable power region near the telephoto end, the lens barrel is guided by a cam groove of the cam barrel and approaches the drive member against the biasing force of the biasing member. Torso

In a zoom lens barrel that holds a zoom lens that performs zooming by changing the distance between a plurality of lens groups and is retractable, a cam barrel having a plurality of cam grooves and a first lens. A first lens barrel that holds the group and moves in the optical axis direction by being guided by the cam groove of the cam barrel; a drive member that is guided by the cam groove of the cam barrel and moves in the optical axis direction; A second lens barrel that holds the lens group and is regulated to be able to approach and separate from the drive member within a predetermined range, and urges the lens barrel and the drive member in a direction to separate them from each other. A biasing member and an interlocking member having one end abuttable on the first lens barrel and the other end engaged with the second lens barrel, and when retracted, the first lens barrel, The second lens barrel and the driving member are image planes. The second lens barrel is moved toward the drive member against the biasing force of the biasing member by moving one end of the interlocking member by the first lens barrel to move it to the vicinity of the wide-angle end. In the variable power region, the second lens frame is driven by the driving member, one end of the interlocking member is separated from the first lens frame, and the second lens frame is moved by the urging force of the urging member. In the zooming area most distant from the driving member and near the telephoto end, the second lens frame is driven by the driving member, and one end of the interlocking member is pressed by the first lens frame to Second
A zoom lens barrel, wherein a lens frame approaches the drive member against the biasing force of the biasing member.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Two embodiments of the zoom lens barrel of the present invention will be described in detail with reference to the drawings.

[First Embodiment] A first embodiment will be described with reference to FIGS. 1 to 5. 1 is a vertical sectional view of the zoom lens barrel retracted, FIG. 2 is a vertical sectional view of the zoom lens barrel extended to the wide-angle end, and FIG. 3 is a zoom lens barrel extended to the telephoto end. FIG. 4 is a developed view of the cam groove of the fixed barrel, and FIG. 5 is a developed view of the cam groove of the cam barrel.

1 to 3, the present zoom lens is composed of a first lens group L1, a second lens group L2 and a third lens group L3, and the first lens group L1 and the second lens group L2 are mutual groups. When the third lens unit L3 is extended, a zooming operation is performed by moving the variable lens while changing the distance between them, and a focusing operation is performed by moving the third lens unit L3, and an image is formed on the image sensor C such as a CCD. When a light image of a subject is formed on the image pickup device C, it is photoelectrically converted into an image signal as is well known, and is subjected to appropriate image processing and then stored in a memory or displayed on a liquid crystal monitor.

The first lens group L1 is the first lens frame 11, the second lens group L2 is the second lens frame 12, and the third lens group L3.
Are respectively held by the third lens frame 13. Also, the first
The outer circumference of the lens frame 11 is fitted with the inner circumference of the straight guide cylinder 14,
The outer circumference of the linear guide cylinder 14 is fitted to the inner circumference of the cam cylinder 15, and the outer circumference of the cam cylinder 15 is fitted to the inner circumference of the fixed barrel 16.

As will be described later, the cam barrel 15 has a plurality of cam grooves on its inner circumference, and has a gear that meshes with a reduction gear connected to a zoom motor (not shown), and is rotated by the zoom motor.

The fixed barrel 16 is a member that serves as a base of the zoom lens barrel, is fixed to the camera body, and holds the image pickup element C. Further, a plurality of guide shafts 17 for guiding the third lens frame 13 straight in the direction of the optical axis O is provided on the fixed barrel 16.
Is erected.

A cam pin 21 is erected on the first lens frame 11 and a cam pin 22 is erected on the second lens frame 12, and the cam pin 21 is provided on the inner circumference of the cam barrel 15 as shown in FIG. Guided by the cam groove 15a, the cam pin 22 moves and is guided along the cam groove 15b provided on the inner circumference of the cam barrel 15.

Further, a cam pin 25 is erected on the cam barrel 15, and the cam pin 25 is fixed to the fixed barrel 16 as shown in FIG.
Engages with a cam groove 16a provided on the inner periphery of the.

The inner circumference of the first lens frame 11 and the second lens frame 1
The drive cylinder 31 is arranged in a gap between the outer circumference of the first lens frame 11 and the outer circumference of the drive cylinder 31. A cam pin 32 is provided upright on the drive cylinder 31, and the cam pin 32 is engaged with a cam groove 15c provided on the inner circumference of the cam cylinder 15 as shown in FIG. In addition, a plurality of guide shafts 3 for guiding the second lens frame 12 straight in the direction of the optical axis O is provided in the drive cylinder 31.
3 is erected, and the compression spring 34 provided on the guide shaft 33.
However, the second lens frame 12 is biased in the direction in which the second lens frame 12 is separated from the drive cylinder 31 in the direction of the image sensor C.

Although the structure of the linear guide cylinder 14 is not shown, a plurality of long grooves formed in the linear guide cylinder 14 in parallel with the optical axis O are engaged with the cam pins 21 and 32, so that the linear guide cylinder 14 is formed. The rear end is engaged with a long groove formed parallel to the optical axis O on the inner circumference of the fixed barrel 16. The linear guide cylinder 14 rotates with respect to the cam cylinder 15, but moves together with the cam cylinder 15 in the direction of the optical axis O. Therefore, even if the cam barrel 15 moves in the optical axis direction while rotating with respect to the fixed barrel 16, the rectilinear guide barrel 14 does not rotate but only moves in the optical axis direction. Therefore, the first lens frame 11 and the drive cylinder 31 do not rotate but only move in the optical axis direction.

Next, the operation of the zoom lens barrel having the above structure will be described. At first, it is assumed that the zoom lens barrel is not in use and is in a retracted state as shown in FIG. When the power switch of the camera body (not shown) is turned on in this collapsed state, the zoom motor rotates and the cam barrel 15 rotates, so that the cam pin 25 of the cam barrel 15 is guided to the cam groove 16a of the fixed barrel 16, The cam barrel 15 is shown in FIG.
Is extended from the retracted position (sink) to the wide-angle end (W). When the cam barrel 15 rotates, the cam pin 21 of the first lens frame 11 is guided by the cam groove 15a of the cam barrel 15, and the first lens frame 11 is extended from the retracted position (sunk) in FIG. 5 to the wide-angle end (W). . Therefore, the first lens frame 11
Added the extension of the cam barrel 15 to his own extension,
As shown in FIG. 2, it will be largely paid out.

At this time, the cam groove 15c of the cam barrel 15 in which the cam pin 32 of the drive barrel 31 is guided is orthogonal to the optical axis O,
There is no change in the direction of the optical axis O. Therefore, the drive cylinder 31 is not extended to the cam barrel 15 at all, but is extended only by the extension of the cam barrel 15 to the fixed barrel 16.

Further, in the collapsed state as shown in FIG. 1, the compression spring 34 is in a compressed state, and the second lens frame 12 is biased by the compression spring 34 in the direction of the image pickup device C, and is moved rearward in the optical axis direction. The end 12a is pressure-bonded to the front end 13a of the third lens frame 13. On the other hand, the cam pin 22 of the second lens frame 12 is loosely fitted in the wide cam groove 15b, and the cam pin 22 is not guided by the cam groove 15b. But,
When the drive cylinder 31 is gradually extended by the extension of the cam barrel 15, the compression spring 34 is gradually extended, and the rear end 12a of the second lens frame 12 is pressed against the front end 13a of the third lens frame 13, The drive barrel 31 and the second lens frame 12 in the direction of the optical axis O are gradually separated.
Eventually, the flange rear surface 12b of the second lens frame 12 comes into contact with the head portion 33a of the guide shaft 33, and the cam pin 22 of the second lens frame 12 is disengaged from the cam barrel 15 toward the image sensor C side as shown in FIG. Become. After this, the drive cylinder 31 is moved to the guide shaft 3
The second lens frame 12 is integrated with the second lens frame 12 via the lens 3, and the second lens frame 12 is not guided by the cam groove 15b of the cam cylinder 15 but is drawn out following the drive cylinder 31. And
The state at the wide-angle end shown in FIG. 2 is obtained.

From the above, the first lens frame 11 is provided at the wide-angle end.
And the second lens frame 12 are most distant from each other, that is, the first lens frame 12
The lens group L1 and the second lens group L2 are in the most separated state.

Here, when the magnification is further changed to the telephoto side, a zoom switch (not shown) in the camera body is operated to rotate the zoom motor and rotate the cam barrel 15. However, in this zoom lens barrel, the fixed barrel 16
The cam groove 16a formed at the wide angle end (W) as shown in FIG.
It is orthogonal to the optical axis O from the end to the telephoto end (T) and has not changed in the optical axis O direction at all. Therefore, the cam barrel 15 only rotates, but is not further extended from the wide-angle end (W).

However, when the cam barrel 15 rotates, the cam grooves 15a, 15b and 15c respectively rotate. Therefore, FIG.
In the process from the wide-angle end (W) to the telephoto end (T), the first lens frame 11 is once retracted to the image sensor C side by the cam groove 15a and then extended again as shown in FIG. Further, the drive cylinder 31 is extended along the locus of the cam groove 15c.
When the drive cylinder 31 is extended, the second cylinder is moved through the guide shaft 33.
The lens frame 12 is moved out following the drive cylinder 31. The cam groove 15c and the cam groove 15b are parallel to each other from the wide-angle end (W) to the predetermined intermediate position (M), and the cam groove 15b
Is wide, the second lens frame 12 merely follows the drive cylinder 31.

From the intermediate position (M) to the telephoto end (T), the width of the cam groove 15b becomes narrow and the cam groove 15b restricts the movement of the cam pin 22. Further, the cam groove 15c is not parallel to the cam groove 15b and has a gentle slope, and the cam groove 15b has a steeper slope. Therefore, the moving speed of the second lens frame 12 becomes faster than that of the drive barrel 31, the second lens frame 12 gradually approaches the drive barrel 31 against the compression spring 34, and the second lens at the telephoto end as shown in FIG. The frame 12 comes closest to the drive cylinder 31. That is, the second lens unit L2 comes closest to the first lens unit L1.

At the wide-angle end, the first lens unit L1 and the second lens unit L2 are most distant from each other during zooming,
At the telephoto end, the first lens unit L1 and the second lens unit L2 move so that they come closest to each other, but since the drive cylinder 31 is provided, as described with reference to FIG. 5, at the wide angle end (W), the second lens frame 12 is moved. With the cam pin 22 separated from the cam barrel 15, the first lens unit L1 and the second lens unit L2 are separated most. Therefore, the total length of the cam barrel 15 can be shortened, and the cam barrel 15 can be sufficiently collapsed when not in use.

It should be noted that the zoom motor can be appropriately stopped between the wide-angle end (W) and the telephoto end (T) to take an image at a desired focal length. Then, a focus motor (not shown) is driven in accordance with the shooting distance to extend the third lens frame 13 along the guide shaft 17, and the optical image of the subject is focused on the image sensor C.

When the magnification is changed from the telephoto end (T) to the wide-angle end (W), the above operation is reversed, the cam barrel 15 rotates in the reverse direction, and the intermediate position (M) changes from the telephoto end (T). Between the first
The lens frame 11, the drive barrel 31, and the second lens frame 12 are all moved toward the image pickup device C side, but the second lens frame 12 is gradually separated from the first lens frame 11 and the drive barrel 31. Then, from the middle position (M) to the wide-angle end (W),
The rear surface 12b of the flange of the second lens frame 12 is brought into contact with the head portion 33a of the guide shaft 33 by the compression spring 34, and the second lens frame 12 is integrated with the drive cylinder 31. It is rolled up to (W).

When retracting from the wide-angle end (W), the cam barrel 15 is retracted, so the first lens frame 11 is retracted and the second lens frame 12 is retracted by the drive barrel 31. On the way, the rear end 12a of the second lens frame 12 is moved to the third end.
Although it abuts on the front end 13a of the lens frame 13, the drive cylinder 31 is further retracted against the urging force of the compression spring 34, and the first lens frame 11 is also retracted, whereby the retracted state of FIG. 1 is obtained.

[Second Embodiment] A second embodiment will be described with reference to FIGS. 6 to 11. 6 is a vertical sectional view when the zoom lens barrel is retracted, FIG. 7 is a vertical sectional view when the zoom lens barrel is extended to the wide-angle end, and FIG. 8 is a vertical sectional view when the zoom lens barrel is extended to the telephoto end. 9 is a development view of the cam groove of the cam barrel, FIG. 10 is an operation view of each lever at the retractable and telephoto ends, and FIG. 11 is an operation view of each lever at the wide-angle end.

In FIGS. 6 to 8, the present zoom lens is composed of a first lens group L1, a second lens group L2 and a third lens group L3, and the first lens group L1 and the second lens group L2 are mutual groups. When the third lens unit L3 is extended, a zooming operation is performed by moving the variable lens while changing the distance between them, and a focusing operation is performed by moving the third lens unit L3, and an image is formed on the image sensor C such as a CCD. When a light image of a subject is formed on the image pickup device C, it is photoelectrically converted into an image signal as is well known, and is subjected to appropriate image processing and then stored in a memory or displayed on a liquid crystal monitor.

The first lens group L1 is the first lens frame 41, the second lens group L2 is the second lens frame 42, and the third lens group L3.
Are held by the third lens frame 43, respectively. Also, the first
The outer periphery of the lens frame 41 is fitted with the inner periphery of the straight guide cylinder 44,
The outer circumference of the linear guide cylinder 44 is fitted to the inner circumference of the cam cylinder 45, and the outer circumference of the cam cylinder 45 is fitted to the inner circumference of the fixed barrel 46.

As will be described later, the cam barrel 45 has a plurality of cam grooves on its inner periphery, and has a gear that meshes with a reduction gear connected to a zoom motor (not shown), and is rotated by the zoom motor.

The fixed barrel 46 is a member that serves as a base body of the zoom lens barrel, is fixed to the camera body, and holds the image pickup element C. Further, a plurality of guide shafts 47 for guiding the third lens frame 43 straight in the direction of the optical axis O are provided on the fixed barrel 46.
Is erected.

A cam pin 51 is erected on the first lens frame 41. As shown in FIG. 9, the cam pin 51 is a cam barrel 45.
Is guided to a cam groove 45a provided on the inner circumference of the.

Further, a cam pin 55 is provided upright on the cam barrel 45, and the cam pin 55 is engaged with a cam groove provided on the inner circumference of the fixed barrel 46. This cam groove is shown in FIG. It has the same shape as the cam groove 16a.

The inner circumference of the first lens frame 41 and the second lens frame 4
A drive cylinder 61 is arranged in a gap between the outer circumference of the first lens frame 41 and the outer circumference of the drive cylinder 61. A cam pin 62 is provided upright on the drive cylinder 61, and the cam pin 62 is engaged with the cam groove 45b of the cam cylinder 45 as shown in FIG. Further, a plurality of guide shafts 63 that guide the second lens frame 42 in the direction of the optical axis O are erected on the drive barrel 61, and a compression spring 64 provided on the guide shaft 63 causes the second lens frame 42 to move. Urges the second lens frame 62 in a direction away from the drive cylinder 61 in the direction of the image sensor C.

Here, the drive cylinder 61 is provided with a rotary lever 65 and a sliding lever 66, which will be described with reference to FIGS. 10 and 11. 10 is a view seen from above in the states of FIGS. 6 and 8, and FIG. 11 is a view seen from above in the state of FIG. 7.

The rotary lever 65 is pivotally supported by a support shaft 61a provided on the drive cylinder 61 and is rotatable about the support shaft 61a. Further, the sliding lever 66 is the support shaft 6 provided on the drive cylinder 61.
The elongated hole 66a is fitted in the 1b, and moves straight in the direction of the optical axis O. A fork 65a provided at one end of the rotary lever 65 engages with an engagement pin 42a provided upright on the second lens frame 42,
A fork 65b provided at the other end of the rotary lever 65 is engaged with an engagement pin 66b provided upright on the slide lever 66.

Although the structure of the linear guide cylinder 44 is not shown, it is the same as that of the linear guide cylinder 14 of the first embodiment, and the cam cylinder 45 rotates with respect to the fixed barrel 46 while the optical axis. Even if it moves in the direction, the linear guide tube 44 does not rotate but only moves in the optical axis direction, and the first lens frame 41 and the drive tube 61 do not rotate but are restricted to move only in the optical axis direction. There is.

Next, the operation of the zoom lens barrel having the above structure will be described. At first, it is assumed that the zoom lens barrel is not in use and is in a retracted state as shown in FIG. When the power switch of the camera body (not shown) is turned on in this collapsed state, the zoom motor rotates and the cam barrel 45 rotates, so that the cam pin 55 of the cam barrel 45 is guided to the cam groove of the fixed barrel 46, and the cam is rotated. The cylinder 45 is extended from the retracted position (sunk) to the wide-angle end (W). Cam cylinder 45
When is rotated, the cam pin 51 of the first lens frame 41 is guided to the cam groove 45a of the cam barrel 45, and the first lens frame 41 is extended from the retracted position (sunk) in FIG. 9 to the wide angle end (W). Therefore, the first lens frame 41 is greatly extended as shown in FIG. 7 by adding the extension of the cam barrel 45 to the extension of itself.

At this time, the cam groove 45b of the cam barrel 45, into which the cam pin 62 of the drive barrel 61 is guided, is orthogonal to the optical axis O,
There is no change in the direction of the optical axis O. Therefore, the drive cylinder 61 is not extended to the cam barrel 45 at all, but is extended only by the extension of the cam barrel 45 to the fixed barrel 46.

Further, in the collapsed state as shown in FIG. 6, the tip portion 66c of the sliding lever 66 penetrates the hole 61c provided in the drive barrel 61 and contacts the back surface 41a of the first lens frame 41. Then, as shown in FIG. 10, the rotary lever 65 is rotated clockwise to bring the second lens frame 42 closer to the drive cylinder 61 against the biasing force of the compression spring 64. But,
As the lens moves from the retracted position to the wide-angle end, the first lens frame 4
1 is paid out, the second lens frame 42 moves the compression spring 6
The urging force of 4 moves in a direction away from the drive cylinder 61, the rotary lever 65 rotates counterclockwise, and the sliding lever 66 slides following the first lens frame 41.
Eventually, the flange rear surface 42b of the second lens frame 42 contacts the head 63a of the guide shaft 63. After that, since the first lens frame 41 is further extended, the tip end portion 66c of the sliding lever 66 is separated from the back surface 41a of the first lens frame 41,
The second lens frame 42 has a flange rear surface 42b having a guide shaft 6
While maintaining the state of contacting the head portion 63a of No. 3, the drive cylinder 61
The distance between and is kept constant. Then, the state at the wide angle end shown in FIG. 7 is obtained.

As described above, the first lens frame 41 is provided at the wide-angle end.
And the second lens frame 42 are most distant from each other, that is, the first lens frame 42
The lens group L1 and the second lens group L2 are in the most separated state.

Here, when the magnification is further changed to the telephoto side, a zoom switch (not shown) in the camera body is operated and the zoom motor is rotated to rotate the cam barrel 45. However, in this zoom lens barrel, the cam groove formed in the fixed barrel 46 with respect to the optical axis O from the wide-angle end (W) to the telephoto end (T) is the same as in FIG. 4 in the first embodiment. They are orthogonal and do not change at all in the optical axis O direction. Therefore,
The cam barrel 45 only rotates, but is not further extended from the wide-angle end (W).

However, when the cam barrel 45 rotates, the cam grooves 45a and 45b respectively rotate. Therefore, as shown in FIG. 9, in the process from the wide-angle end (W) to the telephoto end (T), the first lens frame 11 is once retracted to the image pickup device C side by the cam groove 45a and then re-extended. Further, the drive cylinder 61 is extended along the locus of the cam groove 45b. Drive cylinder 61
Is extended, the second lens frame 4 is moved through the guide shaft 63.
2 is delivered following the drive cylinder 61.

As the magnification is changed to the telephoto end (T), the drive cylinder 61 gradually approaches the first lens frame 41, and eventually the tip portion 66c of the sliding lever 66 is moved to the back surface 41 of the first lens frame 41.
Contact a. Note that the drive barrel 61 is not the first lens frame 41.
As the slider 66 approaches the tip end 66c of the sliding lever 66.
Is pressed by the back surface 41a of the first lens frame 41, and the drive lever 66 retracts. As a result, the rotary lever 65
Rotates clockwise, and the second lens frame 42 moves the compression spring 64.
8 and 10 against the urging force of the drive cylinder 61.
It becomes the state of. Then, at the telephoto end, the second lens frame 42 comes closest to the drive barrel 61, and the second lens group L2 comes closest to the first lens group L1.

At the wide-angle end, the first lens unit L1 and the second lens unit L2 are farthest apart from each other during zooming,
At the telephoto end, the first lens unit L1 and the second lens unit L2 move such that they come closest to each other, but since the drive barrel 61 is provided, the second lens frame 42 moves by a movement amount equal to or greater than the movement amount of the drive barrel 61. To do. That is, since the second lens frame 42 moves by a movement amount equal to or larger than the movement amount of the cam pin 62 of the drive barrel 61,
Compared with the case where a cam pin is provided on the second lens frame 42 and the cam barrel is driven, the total length of the cam barrel 45 can be shortened, and the cam barrel 45 can be sufficiently retracted when not in use.

It should be noted that the zoom motor can be appropriately stopped between the wide-angle end (W) and the telephoto end (T) to take an image at a desired focal length. Then, a focus motor (not shown) is driven in accordance with the shooting distance to extend the third lens frame 43 along the guide shaft 47, and the optical image of the subject is focused on the image sensor C.

When the magnification is changed from the telephoto end (T) to the wide-angle end (W), the above operation is reversed and the cam barrel 45 rotates in the reverse direction, so that the first lens frame 41, the drive barrel 61 and the first barrel The two lens frame 42 is retracted. The drive barrel 61 is gradually separated from the first lens frame 41, and the second lens frame 42 is gradually separated from the drive barrel 61 by the urging force of the compression spring 64. Eventually, the tip portion 66c of the sliding lever 66 becomes the first
The second lens frame 4 is separated from the rear surface 41a of the lens frame 41 and
2, the flange rear surface 42b has a head 63a of the guide shaft 63.
The state of contact with the drive cylinder 61 is maintained and the distance between the drive cylinder 61 and the drive cylinder 61 is kept constant. And in this state, the wide-angle end (W)
Move to.

When retracting from the wide-angle end (W), the first lens frame 41 is rapidly retracted even though the drive cylinder 61 is not retracted with respect to the cam cylinder 45. Therefore,
The first lens frame 41 rapidly approaches the drive barrel 61, and eventually the tip portion 66c of the sliding lever 66 is moved to the first lens frame 41.
Being pressed by the back surface 41a of the drive lever 66, the drive lever 66 retracts. As a result, the rotary lever 65 rotates clockwise, the second lens frame 42 approaches the drive cylinder 61 against the biasing force of the compression spring 64, and the states shown in FIGS. 6 and 10 are obtained.

The two embodiments described above are examples, and the present invention can be included in the scope of the present invention even if the forms are changed as follows.

The cam barrels 15 and 45 may be extended between the wide-angle end (W) and the telephoto end (T).

The cam grooves 15c and 45b are in the retracted position (sink).
And may be inclined at the wide-angle end (W).

The cam grooves 15a and 45a may have any locus between the wide-angle end (W) and the telephoto end (T).

Since the inclination between the intermediate position (M) and the telephoto end (T) in the cam groove 15b is set to be stronger than the inclination between the intermediate position (M) and the telephoto end (T) in the cam groove 15c, The inclination between the intermediate position (M) and the telephoto end (T) in the cam groove 15b is made tighter than the inclination between the wide angle end (W) and the intermediate position (M), and the intermediate position (M) in the cam groove 15c is increased.
The inclination between the telephoto end (T) and the telephoto end (T) may be equal to the inclination between the retracted end (W) and the intermediate position (M).

The lens group of the zoom lens may be two groups or four or more groups. The focusing operation may be performed not only by moving the third lens group, but also by moving other lens groups or by moving all lens groups.

In addition to the above two embodiments, the position of the second lens frame with respect to the drive cylinder may be changed by an actuator such as a motor.

Further, a shape memory alloy is arranged between the drive barrel and the second lens frame, and the shape memory alloy is heated at a predetermined focal length to position the second lens frame with respect to the drive barrel. May be changed.

Although the above-described form is a digital camera in which an optical image of a subject is formed on the image pickup element by a zoom lens, it may be formed in film.

[0065]

According to the zoom lens barrel of the present invention, even if the zoom lens has a large amount of movement of the lens groups, it can be sufficiently retracted without making the entire length of the cam barrel long. Can be formed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view when a zoom lens barrel is retracted.

FIG. 2 is a vertical sectional view when a zoom lens barrel is extended to a wide-angle end.

FIG. 3 is a vertical sectional view when the zoom lens barrel is extended to the telephoto end.

FIG. 4 is a development view of a cam groove of a fixed barrel.

FIG. 5 is a development view of a cam groove of a cam barrel.

FIG. 6 is a vertical sectional view when the zoom lens barrel is retracted.

FIG. 7 is a vertical cross-sectional view when the zoom lens barrel is extended to the wide-angle end.

FIG. 8 is a vertical cross-sectional view when the zoom lens barrel is extended to the telephoto end.

FIG. 9 is a development view of a cam groove of a cam barrel.

FIG. 10 is an operation diagram of each lever at the retracted and telephoto ends.

FIG. 11 is an operation diagram of each lever at the wide-angle end.

[Explanation of symbols]

L1 First lens group L2 Second lens group L3 Third lens group 11,41 First lens frame 12,42 Second lens frame 13,43 Third lens frame 15,45 Cam barrels 15a, 15b, 15c, 16a, 45a , 45b Cam groove 16 Fixed barrel 21, 22, 25, 32, 51, 55, 62 Cam pin 31, 61 Drive cylinder 33, 63 Guide shaft 34, 64 Compression spring 65 Rotating lever 66 Sliding lever

Claims (11)

[Claims] 1. A zoom lens barrel that holds a zoom lens that performs zooming by changing the distance between at least a first lens group and a second lens group.
Of the lens group and the second lens group, the lens group in which the movement distance from the reference position simply increases or decreases between the telephoto end and the wide-angle end in accordance with the change in magnification, has a cam groove in a predetermined zoom region. The zoom lens barrel is characterized in that it is guided by one guide member and is guided by a second guide member different from the first guide member in the other zooming regions. 2. A zoom lens barrel that holds a zoom lens that performs zooming by changing the distance between a plurality of lens groups and is retractable, and a cam barrel having a plurality of cam grooves, wherein: A drive member which is guided by the cam groove of the cam barrel and moves in the optical axis direction, and a lens barrel which holds a predetermined lens group and is regulated to be able to approach and separate from the drive member within a predetermined range. An urging member for urging the lens barrel and the driving member in a direction of separating the lens barrel from each other, and when the lens barrel is retracted, the lens barrel and the driving member are moved to the vicinity of the image forming surface, The lens frame approaches the drive member against the urging force of the urging member, and in a predetermined magnification change region, the lens barrel is driven by the driving member to be driven by the urging force of the urging member. The most distant from the member And a zoom lens barrel. 3. A zoom lens barrel that holds a zoom lens that performs zooming by changing the distance between a plurality of lens groups and is retractable, and a cam barrel having a plurality of cam grooves, wherein: A drive member which is guided by the cam groove of the cam barrel and moves in the optical axis direction, and a lens barrel which holds a predetermined lens group and is regulated to be able to approach and separate from the drive member within a predetermined range. An urging member for urging the lens barrel and the driving member in a direction of separating the lens barrel from each other, and when the lens barrel is retracted, the driving member and the lens barrel move to the vicinity of the image forming surface, The lens frame approaches the drive member against the urging force of the urging member, and in the variable power region near the wide-angle end, the lens frame is driven by the drive member and urged by the urging member. Most spaced from the drive member In the zoom region near the telephoto end, the lens frame is guided by the cam groove of the cam barrel and approaches the drive member against the biasing force of the biasing member. Lens barrel. 4. The zoom lens barrel according to claim 3, wherein the lens barrel comes into contact with a member located near the image plane when the lens barrel is retracted. 5. The cam pin of the lens barrel which engages with the cam groove of the cam barrel is disengaged from the cam barrel toward the image plane side at the wide angle end. The zoom lens barrel described in. 6. The lens barrel holds a second lens group, holds the first lens group on the subject side of the lens barrel, and is guided by a cam groove of the cam barrel to move in the optical axis direction. 4. A lens barrel for one lens is provided.
6. The zoom lens barrel according to any one of 5 to 5. 7. The first lens group and the second lens group at the wide-angle end.
7. The zoom lens barrel according to claim 6, wherein the first lens group and the second lens group are closest to each other at the telephoto end, and the lens group is most distant from the lens group. 8. A zoom lens barrel that holds a zoom lens that performs zooming by changing the distance between a plurality of lens groups and is capable of collapsing, and a cam barrel having a plurality of cam grooves, A first lens barrel that holds one lens group and is moved in the optical axis direction by being guided by the cam groove of the cam barrel; and a drive member that is moved by the cam groove of the cam barrel in the optical axis direction. A second lens barrel that holds the second lens group and is regulated to be able to approach and separate from the drive member within a predetermined range, and urges the lens barrel and the drive member in a direction to separate them from each other. And an interlocking member having one end capable of abutting the first lens barrel and the other end engaged with the second lens barrel, and the first lens mirror when retracted. The frame, the second lens barrel, and the driving member form an image plane And one end of the interlocking member is pressed by the first lens frame to cause the second lens frame to approach the drive member against the biasing force of the biasing member and near the wide-angle end. In the variable power region, the second lens barrel is driven by the driving member, one end of the interlocking member is separated from the first lens barrel, and the second lens barrel is biased by the biasing member. The second lens barrel is driven by the driving member in the variable power region in the vicinity of the telephoto end near the telephoto end, and one end of the interlocking member is pressed by the first lens barrel. The second
A zoom lens barrel, wherein a lens frame approaches the drive member against the biasing force of the biasing member. 9. The first lens group and the second lens group at the wide-angle end.
9. The zoom lens barrel according to claim 8, wherein the first lens group and the second lens group are closest to each other at the telephoto end, and the lens group is most distant from the lens group. 10. The zoom lens barrel according to claim 1, wherein the cam barrel moves in the optical axis direction while rotating. 11. The cam barrel according to claim 10, wherein the cam barrel is extended while rotating from the retracted position to the wide-angle end position, and is not extended between the wide-angle end position and the telephoto end position. Zoom lens barrel.