JP2001042404A - Lens moving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lens groups from mutually interfering when a barrel collapsing action is executed. SOLUTION: A zoom lens 10 is constituted of a 1st to a 3rd lens groups 11-13. The 1st and the 2nd lens groups 11 and 12 are moved in the direction of an optical axis O when a cam barrel 15 is rotated by the driving of a motor for variable power 22. The 3rd lens group 13 is arranged so as to be freely moved with respect to the group 12 and it is moved in the direction of the optical axis O with respect to the group 12 by the driving of a motor for focusing 30. When the barrel collapsing action is executed, the barrel 15 is rotated in a restoring direction by driving the motor 22 and the groups 11-13 are moved to a boundary between a guide area for variable power and a guide area for housing. Thereafter, the group 13 is moved to a housing preliminary position being near to the group 12 by driving the motor 30. Thereafter, the groups 11-13 are moved to a housing position by driving the motor 22 again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens moving device used for a photographic camera, an electronic still camera, and the like.
More specifically, the present invention relates to a lens moving device that moves a lens to a storage position when retracted.

[0002]

2. Description of the Related Art Many cameras using a zoom lens camera have a lens collapsing mechanism, and when not in use, a lens barrel is housed in a camera body for portability. When a lens barrel extension signal is obtained in conjunction with the turning on of the source switch, the lens barrel is extended from the retracted position to the protruding position, and the zooming operation can be performed. Further, when a lens barrel retracting signal is obtained in conjunction with an operation such as turning off a power switch, the lens barrel is retracted from the projecting position to the retracted position.

When the lens barrel is retracted, in order to make the storage space as small as possible, the variable power lens group and the focus lens group in the lens barrel are moved closer to each other by guide means such as a cam barrel and a helicoid mechanism. Moved to In order to simplify the structure of the lens barrel, the guide means for moving each lens group within the zoom range according to the zooming operation has a function of moving each lens group to the storage position, and the lens group at the projecting position A method is known in which all lens groups are simultaneously moved to a storage position while the lens group is moved to a retracted position. Also, a method of providing collapsible guide means different from the guide means for moving each lens group within the variable power range and switching and using these is known from Japanese Utility Model Laid-Open Publication No. 58-40735.

[0004]

When the lens barrel is retracted, the method of moving each lens group to the storage position by the guide means for moving each lens group within the zooming range is common during zooming and retracting. This has the advantage that the basic configuration can be simplified because only the motors need to be driven, but the lens units in the zoom range are moved together to the storage position without interfering with each other in conjunction with the collapse of the lens barrel. Then, the structure of the guide means is likely to be complicated. Further, when the cam cylinder is used as the guide means, the inclination of the cam groove cannot be so steep, so that the rotation angle of the cam cylinder must be increased, so that it takes a long time to retract the cam cylinder. In the case of using the guide means for zooming and the guide means for collapsing, a separate motor is required for each drive, so that an increase in cost cannot be avoided.

The present invention has been made in view of the above circumstances, and uses a guide means for moving a lens group within a variable power range to move these lens groups to a storage position without interfering with each other. It is an object of the present invention to provide a lens moving device which is simple and can be manufactured at low cost.

[0006]

In order to achieve the above object, in the lens moving device according to the first aspect, the first guide means is driven in the retracting direction in response to the lens barrel storage signal to guide the zooming. After moving the first and second lens groups in the area to the boundary with the storage guide area, the second guide means is driven to move the second lens group to the storage preparatory position close to the first lens group. The first and second lens groups are moved to the storage position via the storage guide area by driving the first guide means again in the retracting direction.

In the lens moving device according to the second aspect, the first
The lens group is composed of two lens groups whose lens intervals change with each other by driving the first guide means, and one of these lens groups movably supports the second lens group via the second guide means. It is. Further, in the lens moving device according to claim 3, the second lens group is a focus lens,
The second guiding means is a guiding means for focusing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 3, a zoom lens 10 of a camera comprises three groups of first to third lens groups 11 to 13 in order from the object side. In order to hold the lens groups 11 to 13 and move them in the direction of the optical axis O, the fixed barrel 14, the cam barrel 15, the first lens movable barrel 16, the second lens holding frame 17, and the third lens holding frame 18 And are used.

The first lens unit 1 includes a first lens group 1
1 is fixed, and the second lens group 12 is fixed to the second lens holding frame 17. A straight guide opening 19 extending parallel to the optical axis O is formed in the fixed cylinder 14. A first cam groove 20 for moving the first lens group 11 and a second cam groove 21 for moving the second lens group 12 are formed on the inner periphery of the cam cylinder 15.

A variable power motor 22 is provided outside the fixed cylinder 14.
Has been fixed. The variable power motor 22 rotates the cam barrel 15 about the optical axis O. First lens moving barrel 16
A first cam follower 23 that engages with the first cam groove 20 through the straight guide opening 19 is provided at a position that divides the outer circumference into three. In the second lens holding frame 17, second cam followers 24 that engage with the second cam grooves 21 through the straight guide openings 19 are provided at positions where the outer circumference is divided into three. First and second cam grooves 20, 2
The first lens moving barrel 16 and the second lens holding frame 17 are moved in the direction of the optical axis O by the rotation of the cam barrel 15 between the 1 and the straight guide opening 19.

The first lens moving barrel 16 moves between a position protruding from the fixed barrel 14 toward the subject and a storage position housed inside the fixed barrel. Although not shown,
The outer periphery of the fixed cylinder 14 is covered with the camera body,
When the lens moving barrel 16 is moved to the storage position, it becomes stored in the camera body. Further, the second lens holding frame 17 changes the interval with respect to the first lens holding barrel 16 and comes closest to the storage position. Reference numeral 26 indicates an imaging position.

A guide rod 27 is provided on the second lens holding frame 17.
However, the third lens holding frame 18 is provided with a bearing 28 that engages with the guide rod 27. The guide means including the guide rod 27 and the bearing portion 28 supports the third lens holding frame 18 movably in the direction of the optical axis O with respect to the second lens holding frame 17.

A focusing motor 30 is fixed to the second lens holding frame 17. A feed screw 31 is attached to a shaft of the focusing motor 30. The feed screw 31 is screwed into a screw portion 32 provided on the third lens holding frame 18. As a result, the third lens holding frame 18 changes its distance with respect to the second lens holding frame 17, and comes closest to the storage position and the storage reserve position. The storage position of the third lens group 13 is an absolute position closest to the second lens group 12 when the zoom lens 10 is in the retracted position. The preliminary storage position of the third lens group 13 is a relative position closest to the second lens group 12 when the zoom lens 10 is not at the retracted position. This third lens group 13
Is a focus lens.

The moving positions of the first and second lens groups 11 and 12 are detected by a cam cylinder rotational position detecting unit 31. The cam cylinder rotation position detection unit 31 detects the movement position of the first and second lens groups 11 and 12 by detecting the rotation position of the cam cylinder 15. The cam cylinder rotation position detecting unit 31 includes a code plate 31a provided on the outer periphery of the cam cylinder 15 along a circumferential direction around the optical axis O, and a slider 31b sliding on the code plate 31a. And the slider 31b
Then, a code corresponding to the rotational position of the cam barrel 15 is read from the code plate 31a via the controller and sent to the controller 34. Control unit 3
Reference numeral 4 identifies a magnification position corresponding to the movement position of the first and second lens groups 11 and 12 based on a signal obtained from the cam cylinder rotation position detection unit 31.

The focusing motor 30 is a pulse motor. The control unit 34 drives the focusing motor 30 during the shooting preparation operation to move the third lens group 13 from the storage preliminary position to the focus initial position. Further, at the time of the focusing operation, a pulse signal corresponding to the focusing position determined by the variable power position and the subject distance is sent to the driver 35, so that the focusing motor 30 is driven in a predetermined rotation direction, and the third lens The group 13 is moved from the initial focus position to the in-focus position.
Further, the controller 34 drives the focusing motor 30 after the completion of the exposure to return the third lens group 13 from the in-focus position to the initial focus position. Note that the shooting preparation operation is an operation of changing the camera from a non-use state to a use state. The operation of reversing the state is referred to as a collapsing operation.

A power switch 37, a shutter button 38, a zoom lever 39, and the like provided outside the camera are connected to the control unit 34. In the non-use state, the zoom lens 10 is in a collapsed state. In this state,
The first to third lens groups 11 to 13 are closest to each other when in the storage positions. When the power switch 37 is turned on, the camera is set from a non-use state to a use state. In the use state, the first lens group 11 is extended from the fixed barrel 14 toward the subject, and the zoom lens is set at the wide end.

The zoom lever 39 is, for example, a lever operated in a seesaw type, and one of the telephoto end and the wide end is operated. The control unit 34 drives the variable power motor 22 in the rotation direction in response to the operation of one of the zoom levers 39 by sending a drive signal via the driver 40.

FIG. 4 shows the movement of the zoom lens 10 with respect to the rotational position of the cam barrel 15. Zoom lens 10
Is moved between the retracted position and the wide position. The tele position is set between the retracted position and the wide position.
When the zoom lens 10 is at the retracted position, the rotational position of the cam barrel 15 is the initial position. The rotation of the cam barrel 15 in the feeding direction is a direction from the initial position to the end position. When the cam barrel 15 is at the initial position, the zoom lens 10 is set at the retracted position, and when at the end position, the zoom lens 10 is set at the wide position.

The rotation range of the cam barrel 15 includes a variable power range and a storage range. The variable magnification area is a rotation area of the cam barrel 15 at the time of zooming, and the storage area is an area in which the cam cylinder 15 rotates during a shooting preparation operation or a retracting operation. In the variable power range, the shapes of the first and second cam grooves 20 and 21 are determined in order to move the first and second lens groups 11 and 12 in the direction of the optical axis O so that the distance between the first and second lens groups is different. Have been. Thus, when the cam barrel 15 is rotated in the zoom range between the tele position and the wide position, the focal length of the zoom lens 10 changes continuously.

In the storage area, the first set at the zooming position
The shapes of the first and second cam grooves 20, 21 are determined so that the first and second lens groups 11, 12 are moved to the storage positions, respectively. Then, after the third lens group 13 is moved to the storage preliminary position H by the driving of the focusing motor 30, the third lens group 13 moves together with the second lens group 12 and is set to the storage position. When the third lens group 13 is in the storage preliminary position H
Is set when the cam barrel 15 is rotated to the rotation position F in the storage area. In addition,
The rotation position F may be any position in the storage area. Also, the boundary between the variable power range and the storage range, that is, the zoom lens 10
May be set as the rotation position F.

In the retracting operation, the variable power motor 22 is driven intermittently.
Is driven. That is, as shown in FIG. 5, the control unit 34 temporarily stops the driving of the variable power motor 22 from time t1 when the cam barrel 15 reaches the rotation position F to time t4. Then, while the driving of the variable power motor 22 is stopped,
The focusing motor 30 is driven by a predetermined pulse. Accordingly, the third lens group 13 is moved from the focus initial position I to the storage preliminary position H between the time t2 and the time t3.

On the other hand, the variable power motor 22 is driven toward the initial position again at a time t4 when a predetermined time has elapsed from the time t3 when the driving of the focusing motor 30 is stopped, and the cam barrel 15 is moved to the initial position. At the time t5 when the driving is reached, the driving is stopped. Thus, the retracting operation is completed. At this time, the first lens group 11 and the second lens group 12 are located at the storage positions J and K, respectively. Then, the third lens group 13 moves together with the second lens group 12 and is located at the storage position L.

At the time of the shooting preparation operation, the same as at the time of the collapsing operation,
When the cam barrel 15 reaches the rotation position F, the driving of the zooming motor 22 is temporarily stopped, and during the stop of the driving, the focusing motor 30 is driven by a fixed pulse to house the third lens group 13. It is moved from the preliminary position H to the focus initial position I. Then, the third lens group 13 moves together with the second lens group 12 by re-driving the zooming motor 22 thereafter, and moves from the initial focus position I at the tele position to the initial focus position at the wide position. Move to position M.

Here, the initial focus position of the third lens group 13 is a position set when the focusing operation is performed. Since this position moves together with the second lens group 12, zooming is performed. The position differs within the variable magnification range on the line indicated by reference numeral 13 in FIG. For example, the initial focus position at the telephoto position is the position indicated by reference numeral I in the same drawing, and the initial focus position at the wide position is the position indicated by reference numeral M. The shape of the second cam groove 21 is such that the position of the second lens group 12 on the optical axis O is the same when the cam barrel 15 rotates to the tele position and when the cam cylinder 15 rotates to the rotation position F. Is determined. Therefore, the position on the optical axis O of the third lens group 13 at the telephoto position is the same as the focus preparatory position I when the cam barrel 15 is rotated to the rotation position F.

Next, the operation of the above embodiment will be described. When the camera is not used, the zoom lens 10 is in the retracted position. In the retracted position, as shown in FIG.
The first lens moving barrel 16 is retracted into the fixed barrel 14 at the storage position J, the second lens holding frame 17 is positioned at the storage position K close to the first lens moving barrel 16, and the third lens holding barrel 17 is further held. The frames 18 are set at the storage positions L close to the second lens holding frame 17, respectively.

To put the camera in use, the power switch 37 is turned on. The control unit 34 includes a power switch 37
In response to ON, the variable-power motor 22 is driven to rotate forward. The drive of the motor 22 is transmitted to the cam barrel 15. Thereby, the cam cylinder 15 rotates toward the terminal position. When the cam cylinder 15 rotates, the first and second cam grooves 2
The first lens moving barrel 16 and the second lens holding frame 17 are respectively extended toward the subject by the action of 0, 21 and the straight guide opening 19. Then, the third lens holding frame 18 moves together with the second lens holding frame 17.

The control unit 34 includes a cam cylinder rotation position detection unit 31
When it is determined that the cam barrel 15 has reached the rotation position F, the driving of the variable power motor 22 is temporarily stopped. At this time, time t4 shown in FIG. 5 is reached. Thereafter, at time t3 after a lapse of a predetermined time after the driving of the variable power motor 22 is stopped, a signal for a predetermined pulse is sent to drive the focusing motor 30. The driving of the focusing motor 30 is transmitted to the screw portion 32 of the third lens holding frame 18 via the feed screw 31. Then, at time t2 when the driving for the predetermined pulse is completed, the third lens holding frame 18 moves to the focus initial position I. The control unit 34 measures the time by a built-in timer circuit.

At time t1 after a lapse of a predetermined time since the driving of the focusing motor 30 is stopped, the control unit 34 drives the variable power motor 22 to rotate forward again. Then, when the control unit 34 determines that the cam cylinder 15 has reached the terminal rotation based on the signal from the cam cylinder rotation position detection unit 31, the control unit 34 stops the driving of the variable power motor 22. As a result, at time t0, the zoom lens 10 is set to the wide position, and the camera is in use. At this time, the third lens group 13 is located at the focus initial position M at the time of the wide position shown in FIG.

When taking a picture, the zoom lever 39 is operated to perform zooming. At the time of this operation, the control unit 34 drives the zoom motor 22 in the rotation direction corresponding to the operation of the tele end or wide end lever for a time corresponding to the operation. As a result, the cam barrel 15 rotates within the zooming range, and the zoom lens 10 is set at a desired zooming position. At this time, the third lens group 13 moves together with the second lens group 12, and is set to the focus initial position corresponding to the zoom position.

In response to the half-press operation of the shutter button 38, the control section 34 performs distance measurement and photometry. The in-focus position of the third lens group 13 is specified from the subject distance obtained from the distance measurement result and the zoom position at that time. In addition,
The in-focus position is stored in the memory 40 in advance as the amount of movement of the third lens group 13, and the amount of movement determined for each subject distance differs for each magnification position.

The control section 34 sends a pulse signal corresponding to the read amount of movement to the driver 35,
Drive. Accordingly, the third lens holding frame 18 moves from the focus initial position corresponding to the current zoom position to the direction approaching the second lens holding frame 17, and
The lens moves to a focus position corresponding to the subject distance within the focus range G shown in FIG. Thereby, the focus of the zoom lens 10 is focused on the subject. Then, by performing the full-press operation of the shutter button 38 subsequently to the half-press operation, the shutter mechanism is operated with the exposure corresponding to the photometry.
Then, after the exposure operation is completed, the focusing motor 30 is driven to return the third lens group 13 to the focus initial position corresponding to the previous zoom position. Note that the focusing operation may be performed by fully pressing the shutter button 38, and the exposure operation may be performed after a lapse of a predetermined time from the completion of the focusing operation.

After the photographing is completed, the power switch 37
Is turned off to put the camera in a non-use state. The control unit 34 drives the variable power motor 22 to rotate in reverse in response to the turning off of the power switch 37. By this driving, the cam cylinder 15
Is rotated toward the initial position which is the retraction direction. Then, the time t when the rotation position of the cam cylinder 15 reaches the rotation position F
At 1, the driving of the variable power motor 22 is temporarily stopped. Then, at time t2 after a lapse of a predetermined time after the driving of the variable power motor 22 is stopped, the focusing motor 30 is driven by a predetermined pulse. Thereby, the third lens group 13 moves in a direction approaching the second lens group 12.
Then, at time t3, the driving of the focusing motor 30 is stopped, and the third lens group 13 is set at the storage preliminary position H.

At time t4 after a lapse of a predetermined time since the driving of the focusing motor 30 is stopped, the reverse rotation driving of the variable power motor 22 is restarted. Thus, the cam barrel 15 is rotated toward the initial position again, and the drive of the variable power motor 22 is stopped at time t5 when the cam barrel 15 reaches the initial position. Thereby, the first and second lens groups 11, 12
Are set at the storage positions J and K, respectively. Then, the third lens group 13 moves together with the second lens group 12 and is set at the storage position L.

As described above, during the retracting operation, the cam cylinder 15
Temporarily stops the driving of the variable power motor 22 when the camera is in the storage area, and drives the focusing motor 30 during the stop to stop the third motor.
The second lens group 12 is moved to the storage position K before the third lens group 13 is moved to the preliminary storage position H because the third lens group 13 is moved to the preliminary storage position H. For example, it is possible to reliably prevent the third lens group 13 from interfering with an aperture or the like arranged at the rear end of the lens barrel.

Here, the second lens group 1 of the above embodiment is described.
2 is the first lens group of the present invention, and the third lens group 1
Reference numeral 3 corresponds to the second lens group of the present invention. Further, the first guide means of the present invention is provided on the variable power motor 22, the first and second cam grooves 20, 21, the first and second cam followers 23, 24, the straight guide opening 19, etc. of the above embodiment, and , Second
The guide means corresponds to the focusing motor 30, the feed screw 31, and the like.

In the above embodiment, the variable power moving mechanism is a cam mechanism. However, the present invention is not limited to this, and may be a helicoid mechanism. Further, although the focus moving mechanism is the feed screw 31, a cam mechanism or a helicoid mechanism may be used instead.

In the above embodiment, the variable power position is identified by the rotational position of the cam cylinder 15. However, the present invention is not limited to this, and may be identified by the rotation amount of the cam cylinder 15. , The first and second lens groups 11 and 12 may be identified by the amount or position of movement. In these cases, the third lens group 13 is moved to the storage position H based on a signal obtained from the unit for identifying the zoom position.

In the above embodiment, the zoom lens has a three-group configuration. However, the present invention is not limited to this, and may have a two-group configuration or a configuration of four or more groups. In addition, the first to third lens groups 11 to 13 are arranged in order from the subject side, but the present invention is not limited to this order.
The third lens group 13 may be arranged on the object side of the lens group 12 of the above. Further, the present invention can be applied not only to a zoom lens camera but also to a bifocal camera that switches between a telephoto position, a wide position, and a retracted position, for example. Furthermore, although the tele position is set between the retracted position and the wide position, it is also possible to set the wide position between the retracted position and the tele position. In this case, the boundary between the guide area for zooming and the guide area for storage is the wide position.

In the above embodiment, the power switch 3
Although the lens barrel extending or retracting signal is identified in response to the operation of 7, the present invention is not limited to this. For example, a protective cover for protecting the taking lens can be opened and closed on the front of the camera. May be configured so that a lens barrel extending or retracting signal is identified in response to an opening / closing operation of the protective cover.

Further, the present invention provides, in addition to a photographic camera,
For example, the present invention can be applied to an electronic still camera. In this case, instead of the distance measuring mechanism, a contrast method for determining whether or not focusing is performed using the contrast of an image obtained from the CCD is used, and a focusing operation is performed based on a signal obtained from this method. You may do so.

Furthermore, in the above-described embodiment, the magnification changing motor 22 is used in the photographing preparation operation as in the retracting operation.
Is driven intermittently, and the focusing mora 30 is
To move the third lens group 13 to the focus initial position M
Instead of this, for example, the cam barrel 15 is rotated to the end position without stopping the driving of the magnification motor 22 at the time of the photographing preparation operation, and the focusing motor 30 is driven during the driving. May be driven to move the third lens group 13.

As another example, as shown in FIG. 6, during the photographing preparation operation, the variable power motor 22 is driven from time t6 to time t7 to rotate the cam barrel 15 all the way to the end position. The focusing motor 30 may be driven to move the third lens group 13 to the initial focus position M at a time t8 after a predetermined time has elapsed after the driving of the zooming motor 22 is stopped. In this manner, the driving of the variable power motor 22 is continued only during the shooting preparation operation, and the cam barrel 1 is driven.
By rotating the 5 at a time to the end position, the camera can be quickly used.

[0043]

As described above, in the lens moving device of the present invention, the first guide means is driven to move the first and second lens groups to the boundary with the storage guide area, and then the second guide means is provided. Is driven to move the second lens group to the preliminary storage position, it is possible to reliably prevent interference when the lens group moves to the storage position. In addition, there is no need to provide a separate mechanism for moving the camera to the storage position as described in the related art, so that the cost and size of the camera can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a zoom lens using a lens moving device according to the present invention, showing a state of a collapsed position.

FIG. 2 is a cross-sectional view showing the zoom lens at a telephoto position.

FIG. 3 is a cross-sectional view showing the zoom lens at a wide position.

FIG. 4 is an explanatory diagram showing a movement amount of a zoom lens in an optical axis direction with respect to a rotation amount of a cam barrel.

FIG. 5 is an explanatory diagram showing driving of a zooming and focusing motor during a retracting operation.

FIG. 6 is an explanatory diagram of another example in which the cam barrel is rotated to the end position at the same time during a shooting preparation operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Zoom lens 11 1st lens group 12 2nd lens group 13 3rd lens group 16 1st lens moving cylinder 17 2nd lens holding frame 18 3rd lens holding frame 14 Fixed cylinder 15 Cam cylinder 22 Magnification motor 30 Focusing motor 31 Cam cylinder rotation position detector

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Eiichi Kabe 1-3324 Uetakecho, Omiya City, Saitama Prefecture Fuji Photo Optical Co., Ltd. F-term (reference) 2H044 DA01 DA02 DA04 DB02 DC01 DD03 2H101 DD62

Claims (3)

[Claims] The first guide means is driven in the extension direction in response to a lens barrel extension signal, and the first and second lens groups located at the accommodation positions close to each other are moved in the optical axis direction, respectively, so that the accommodation guide is provided. The first and second lens groups are moved by driving the first guide means, and the second lens group is moved by the second guide means within the guide area for zooming. In a lens moving device adapted to move with respect to a first lens group, the first and second lenses are driven in a retracting direction in response to a lens barrel storage signal to move the first and second lenses in a zooming guide area. After moving the group to the boundary with the storage guide area, the second
The guide means is driven to move the second lens group to the storage preparatory position close to the first lens group, and the first guide means is driven again in the retracting direction to move the first and second lens groups to the storage guide area. Characterized in that the lens moving device is moved to the storage position via the lens. 2. The first lens group is composed of two lens groups whose lens intervals change with each other by driving the first guide means, and the second lens group is provided with the second guide means in one of these lens groups. The lens moving device according to claim 1, wherein the lens moving device is movably supported through a lens. 3. The lens moving device according to claim 2, wherein said second lens group is a focus lens, and said second guide means is a guide means for focusing.