JP2000193876A - Variable focal distance optical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical instrument variable in focal distance in which an optical unit is not moved by the effect of the backlash by the external force irrespective of the focal distance change and stop position of the optical unit. SOLUTION: If zooming action is stopped (S014), and the stop position of a lens barrel when the zooming action in the direction of the long focal distance is stopped is on the focal point end side shorter than the extreme value (S015), or the stop position of the lens barrel when the zooming action in the direction of the short focal length is stopped is on the longer focal point end side than the extreme value (S020), the motor is controlled so that the lens barrel is moved over the stop position in the take-in direction, and then taken out to the stop position (S016).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable focal length optical device such as a camera for performing a zoom operation or the like using an actuator as a power source.

[0002]

2. Description of the Related Art Conventionally, in a zoom lens camera which performs a zoom operation, a cam ring is used as a means for driving a lens for performing a zoom operation. It is formed in a shape as shown in FIG. The cam groove 101 of the cam ring 100 drives the variator lens. A cam pin provided on the lens barrel holding the variator lens fits into the cam groove 101, and the rotation of the cam ring 100 causes the lens barrel to move into the camera body. It moves between the retracted retracted position and the telephoto end (TELE end). In the retracted position, a barrier (not shown) provided at the front end for protecting the lens is closed.

[0003]

In such a conventional zoom mechanism, when the zoom operation is performed from the wide side to the tele side, the variator lens is extended monotonically (without performing the retraction operation in the middle), and the telescopic lens is moved. From the side to the wide side, there is a cam groove that is monotonously retracted (without advancing operation in the middle), and a lens barrel having a variator lens is driven by a zoom motor and a gear train of a DC motor, Move in the optical axis direction.

[0004] By the way, there is a backlash in the gear train, and when the lens barrel having the variator lens is driven from the wide side to the tele side, it moves to the tele side, and when it is driven from the tele side to the wide side, it moves to the wide side. Existing.

[0005] Regardless of whether the operator performs a zoom operation from the tele side to the wide side or a zoom operation from the wide side to the tele side, in order to always stop at the same zoom position, the offset operation for removing backlash. Is required.

A problem arises when the lens barrel is driven from the telephoto side, which has long protruded from the camera body to the subject side, to the wide side, where it is retracted into the camera body side. However, if an external force such as accidentally pushing the lens barrel is applied, the backlash-equipped lens barrel is pushed, and the photographing magnification changes.

In view of the above, in the case of driving from the tele side to the wide side, a one-sided operation is performed, that is, after the lens barrel is further extended from a position desired by the operator, the lens barrel is extended. Thus, there has been proposed an apparatus in which backlash of the gear train is removed, and the gear train is stopped at a stop position desired by the operator to solve the problem.

On the other hand, as shown in FIG. 10 (B), there is a cam groove 201 provided in a cam ring 200 having an extreme value between wide and tele positions. The lens moves to the subject side up to the extremum, and the lens moves toward the subject side after passing the extremum.

In such a zoom mechanism, it is assumed that the zoom operation is stopped during the zoom operation in the telephoto direction between the wide end and the extreme value (the rotation of the gear in this direction is referred to as a forward rotation direction). In this case, the backlash generated in the gear train for driving the cam ring exists in the normal rotation direction of the gear. At this stop position, the direction of the lens barrel toward the extreme value direction is the above-described forward rotation direction. Therefore, when any external force is applied to the lens barrel, the lens barrel is retracted, and the photographing magnification changes. Become.

In order to eliminate such a problem, it is necessary to perform a one-sided operation. However, in the case of performing the one-sided operation by a conventional method, the one-sided operation is performed only when the lens barrel is moved from the tele side to the wide side. Therefore, when the lens barrel is driven from the wide side to the telephoto side in this way, the one-sided movement is not performed, and the operator pushes the lens barrel or the lens barrel hits an obstacle. When an action is applied from the outside, the lens barrel is slightly retracted, and the photographing magnification may be changed.

An object of the present invention is to provide a variable focal length optical apparatus in which the optical unit does not move due to external force due to backlash regardless of the focal length change stop position of the optical unit. It is.

[0012]

SUMMARY OF THE INVENTION In order to achieve the object of the present invention, in a variable focal length optical apparatus, a focal length is changed from one of a short focal length end and a long focal length end to the other. An optical unit whose moving direction changes from one of the extending direction and the retracting direction to the other halfway, and which may receive an external force in the retracting direction, and the optical unit based on a position of the optical unit and a focal length changing direction. When it is determined that the optical unit moves in the retracting direction and stops at the stop position, the optical unit is moved in the retracting direction beyond the stop position, and then moved in the extending direction to stop at the stop position. And control means.

[0013]

(Embodiment) FIGS. 1 to 9 show an embodiment of the present invention, and FIG. 1 is an exploded perspective view of a lens barrel showing an embodiment of a camera embodying the present invention. FIG.

Reference numeral 1 denotes a base which is a base of the lens barrel unit.
The lens barrel unit structure is formed together with the fixed barrel 2 fixed to the front end by screws. 3 is a first lens barrel,
It holds a plurality of lenses (not shown). Three follower pins 7 each having a tapered portion at the tip are press-fitted on the outer peripheral side surface, and a cap (not shown) is fixed to the front surface by bonding.

Reference numeral 9 denotes a second group lens barrel which holds a plurality of lenses (not shown), and is integrally held on a diaphragm base plate of the diaphragm unit 13 by means such as bonding.

Reference numeral 15 denotes a third-group lens barrel holding a lens for focus adjustment, which is guided by guide bars 17 and 18 extending in the optical axis direction, and has an axial position at which a screw 21 held between its arms is provided. It is regulated by a nut (not shown) having a female screw to be screwed, and is biased by a tension spring 20 in the feeding direction. The projection of the third lens barrel 15 is fitted in a slit provided in the nut, and rotation is restricted. Reference numeral 21 denotes a screw provided integrally with the magnet 22, and has a male screw portion screwed with the female screw portion of the nut. One end of the screw 21 is rotatably fitted to the bearing press-fitted into the base 1. Reference numeral 24 denotes a step motor for driving the third lens barrel 15, which comprises a magnet 22 and forms a magnetic circuit.
Fixed on top. The position detection of the third group lens barrel 15 is performed when the slit plate 30 fixed integrally is passed through a slit portion of a photo interrupter (not shown) fixed to the base 1.

Reference numeral 32 denotes an image sensor, which is fixed and held to a holding plate 33 fixed to the base 1 with screws by bonding or the like. Reference numeral 34 denotes a flexible circuit for supplying the photoelectrically converted image signal to a signal processing circuit described later. Numeral 35 denotes dustproof rubber, and numeral 36 denotes a low-pass filter (LPF), both of which are fixed to the base 1 by adhesion or the like.

A drive ring 37 is rotatably fitted to the outer periphery of the fixed cylinder 2. As shown in FIG.
Has a gear portion 37a in a part thereof. Reference numeral 38 denotes a zoom motor, and a pinion gear 39 is integrally provided on the output shaft by press-fitting or the like. The driving force of the motor 38 is, in order from the gear 39, the gears 40, 41, 42, 43, 44,
The power is transmitted to the gear portion 37 a of the drive ring 37 through the line 45. These gears 40-45 are gearboxes 46, 47
And is fixed to the base 1. The motor 38 is also fixed to the gear box 46.

A movable cam ring 48 is fitted on the inner peripheral portion of the fixed cylinder 2, and a linear guide cylinder 49 is fitted on the inner peripheral portion thereof. A drive pin 50 and a follower pin 51 having a tapered portion are equally set on the outer periphery of the movable cam ring 48, and the drive pin 50 has a hole in the fixed cylinder 2 as shown in FIGS. Groove portion 3 provided on the inner peripheral side of drive ring 37 through portion 2a
7b.

The follower pin 51 has a tapered tip portion in sliding contact with a tapered cam groove 2b provided on the inner periphery of the fixed cylinder 2 shown in FIG. FIGS. 2 and 6 are developed views of the inner surface for explaining the above.

The moving cam ring 48 has a not-shown 2
The first group lens barrel 3 is provided with various kinds of tapered cam grooves.
And the follower 7 of the aperture unit 13 are in sliding contact with each other. At the same time, the side surface of each follower is fitted in the linear grooves 49a and 49b of the straight guide cylinder 49, and the position in the rotation direction is regulated.

The front projection 49c on the outer periphery of the straight guide cylinder 49 is in contact with the groove 48c on the inner periphery of the moving cam ring 48, and the rear flange portion 49d is connected to the end of the moving cam ring 48. The linear guide cylinder 49 is thereby restricted from moving relative to the movable cam ring 48 in the optical axis direction. At the same time, the rear projection 49e is fitted in the straight groove 2c on the inner periphery of the fixed cylinder 2 so as to be able to move straight, and the movement in the rotation direction is restricted.

Reference numeral 52 denotes a cap which holds a dustproof sheet (not shown) between the cap and the fixed cylinder 2 and has rails 52a and 52b on its front surface for guiding a barrier 54 to be described later.
Are formed.

Reference numeral 56 denotes a linear sensor composed of a variable resistor, which is fixed to the base 1 by a screw or the like. Reference numeral 57 denotes a lever for holding the slider of the variable resistor.
Guided to 8. Reference numeral 59 denotes a spring for biasing the lever 57. The rotation angle of the drive ring 37 is detected by A / D converting the voltage between the terminals of the linear sensor 56, and 1
The position of the group lens barrel 3 can also be detected.

In FIGS. 1 and 3, the barrier 54 is
It is supported rotatably about a shaft 63 erected on the barrier base 62, and is urged clockwise as viewed from the front of the camera by a closing spring 64 hung on a hook 54a of the barrier 54.

Reference numeral 65 denotes a barrier drive lever, which is supported rotatably about a shaft 66 erected on the barrier base 62, and an opening spring 67 is hooked on the hook 65a to be urged clockwise. . Here, the spring force of the two springs is set as "close spring 64 << open spring 67".

A shaft 68 is provided at one end of the barrier drive lever 65 at a position corresponding to one side surface of the barrier 54. 69 is a leaf switch provided by integral molding,
It is fixed to the barrier base 62 by screws. The barrier base 62 is fixed to the base 1 with screws.

FIG. 3A shows a state in which the barrier is closed. When the stepped portion 37f of the drive ring 37 comes into contact with the bent portion 65b of the barrier drive lever 65, the barrier drive lever 65 is opened. In a counterclockwise direction against the urging force. The barrier 54 rotates in the closing direction by the urging force of the closing spring 64, and the bent portion 54 b contacts the stopper 2 d of the fixed cylinder 2 to be in a closed state.

The operation of the above configuration will be described below.

When the zoom motor 38 is driven, the drive ring 37 rotates via the gears 39 to 45 as described above,
The moving cam ring 48 rotates via the driving pin 50, but moves along the cam 2 b of the fixed cylinder 2 via the follower pin 51, so that the moving cam ring 48 also moves in the optical axis direction. When the movable cam ring 48 moves in the optical axis direction, the straight guide cylinder 49 also moves in the optical axis direction. Only move.

When the moving cam ring 48 rotates, the first lens barrel 3
The second lens barrel fixed to the aperture unit 13 relatively moves in the optical axis direction along the grooves 49a and 49b of the rectilinear guide cylinder according to the lift of each cam of the movable cam ring 48, respectively.

FIGS. 5A and 5B show only the trajectory of the cam portion. FIG. 5A shows the cam of the fixed cylinder 2 and FIG.
(C) shows the movement trajectory of the first lens barrel (a)
And (b). In the cam locus shown in FIG. 5C, when the first lens barrel 3 is driven, retraction and retraction are performed at an extreme value between wide and tele.

This cam has a flat area from the retracted position S to the position indicated by B.

In this way, by driving the zoom motor 38, switching between the retracted position and the photographable position (S to W),
The zoom operation (W to T) in the shooting range is performed.

When the drive ring 37 rotates, the lever 5
Reference numeral 7 moves in the optical axis direction along a cam (not shown) to displace the slider of the linear sensor 56. By detecting this output, the zoom position can be sequentially detected, and the extreme value can be detected. You can do it.

As described above, the stepped portion 37f of the drive ring 37 locks the barrier drive lever 65b when retracted. However, when the drive ring 37 rotates, the lock is released, and the barrier drive is released. The lever 65 is rotated clockwise by the urging force of the opening spring 67 and presses the side surface of the barrier 54 via the shaft 68.

As described above, since the urging force of the closing spring 64 is weaker than the urging force of the opening spring 67, the barrier 54 is rotated counterclockwise to the open state shown in FIG. 3B. At this time, when no external force is acting on the barrier drive lever 65, the bent portion 54b of the barrier 54 bent into an L-shape presses the section 69a of the leaf switch 69,
Since the switch is turned on, the state where the barrier 54 is open can be electrically detected.

However, when the lens barrel is collapsed, that is, when it is not in the photographing state, the notch 37f of the drive ring 37 acts on the hook 65b of the barrier lever 65 and is lowered. At this time, the barrier 54 is closed by the action of the biasing closing spring 64.

The opening and closing operation of the barrier 54 is set so as to be completed in a flat area of each cam shown in SB of FIG.

FIG. 8 is a block diagram of a control device for driving the above-mentioned lens barrel.

Reference numeral 71 denotes a lens barrel, and components included in the drawing are denoted by the same reference numerals as those of the above-mentioned members.

The image signal photoelectrically converted by the image pickup device 32 is subjected to predetermined processing such as color conversion and gamma processing by a signal processing circuit 72 and then recorded in a memory 73 such as a card medium. The control unit 74 controls the entire camera, and controls the step motor 24, the zoom motor 38, and the aperture unit 13 while monitoring the outputs of the linear sensor 56, the photo interrupter (not shown), the leaf switch 69, and the like inside the lens barrel. In addition, the signal processing and the control of the memory 73 are also performed. Reference numeral 75 denotes an electrically erasable / recordable nonvolatile memory, for example, an EEPROM or the like. Reference numeral 76 denotes a mode dial switch, which can switch and set various function modes such as a power-off mode, a shooting mode, a playback mode, and a PC (personal computer) connection mode. Reference numeral 77 denotes a zoom switch, which outputs signals in the zooming direction in the tele direction and the wide direction, and the zoom motor 38 rotates forward or backward according to these signals.

The operation of the above-described control device is shown in the flowchart of FIG.

In the flowchart of FIG. 7, when the power is turned on (S001), the zoom motor 38 rotates forward (S002), and is transmitted to the gear 37a of the drive ring 37 via the gears 39 to 45, and the drive ring 37 is rotated. Is rotated counterclockwise with respect to FIG.

In S003, it is determined whether the barrier 54 is at the open position. The opening position of the barrier 54 is the driving ring 3
The rotation angle of the drive ring 37 can be detected by the linear sensor 56. Drive ring 37
Is rotated to the open position of the burr 54, the barrier drive lever 65 is rotated clockwise in FIG. 1 by the action of the opening spring 67, and the barrier hook 68 of the barrier drive lever 65 pushes down the barrier 54, and FIG. The state shown in FIG.

At this point, the zoom motor 38 is stopped (S
004) In step S005, a timer for setting a predetermined time is started.

In step S006, leaf switch 69
Is turned on, that is, whether the barrier 54 is completely opened.

When the barrier 54 is completely opened,
The bent portion 54b of the barrier 54 is a leaf switch contact 6
9a, and if the leaf switch 69 is not turned on in the barrier 54, the process proceeds to step S007, and the process proceeds to step S0.
It is determined whether or not the timer time set in 05 has elapsed, and if it is within the timer time, the process returns to step S006, and this operation is repeated until the leaf switch 69 is turned on within the predetermined timer time. That is, it waits until the barrier 54 is completely opened.

In step S007, if it is not detected that the barrier 54 is completely opened within the predetermined timer time, it is determined that an error has occurred in the barrier opening operation, and an error code (for example, a code 1 indicating an error in the barrier opening operation).
5) is substituted and error processing is performed.

The follower 7 of the first lens barrel 3 moves on the section AA 'in FIG. 10B from the start of rotation of the drive ring 37 to the opening of the barrier 54 when the power is turned on. Therefore, the first lens barrel 3 is not extended during that time.

Therefore, by stopping the rotation of the zoom motor in the section AA ′, even if an error occurs in the barrier opening operation, the first lens barrel 3 is extended and the barrier 5 is moved.
No four hits.

On the other hand, if it is detected that the leaf switch 69 is turned on and the barrier 54 is completely opened within a predetermined timer period, the process proceeds to step S010.

In step S010, after detecting that the leaf switch 69 has been turned ON, the drive ring 37 is again rotated by the zoom motor 38, and the movable cam ring 48 is rotated together therewith. The movable cam ring 48 moves in the optical axis direction along the cam groove 2b of the movable cam ring 2b.

Further, with the rotation of the movable cam ring 48, the first lens barrel 3 is moved to the cam groove 48 formed on the inner surface of the movable cam ring 48.
Move along a. The first lens barrel 3 is moved to the wide position W in FIG.
Up to shooting. The moving position of the first lens barrel 3 is confirmed by the detection information of the linear sensor 56, and when the wide position W is reached, the driving of the zoom motor 38 is stopped.

According to the present embodiment, when the power is turned on,
The first lens barrel 3 is driven once from the retracted position to the barrier open position, and after it is confirmed that the barrier 54 is completely opened,
Since it is driven to the wide position, it does not hit the barrier 54.

Thereafter, when the operator performs a zoom operation, the zoom motor 38 rotates, the drive ring 37 rotates, whereby the variator lens moves, the photographing magnification changes, and a zoom position desired by the operator is selected. can do.

The A / D conversion value of the voltage between the terminals of the linear sensor 56 according to the above-described positions of the first lens barrel 3 and the following zoom position and extreme value P is stored in the nonvolatile storage element 75 in advance. The position of the first lens barrel 3 can be electrically detected by reading the A / D value of the linear sensor 56.

Next, the zoom operation will be described with reference to the flowchart of FIG.

The feature of this zoom operation is that the first lens barrel 3
When the vehicle stops before reaching the extreme value P while moving from the wide side to the tele side, and when the vehicle stops before reaching the extreme value P while moving from the tele side to the wide side, backlash of the zoom gear trains 39 to 45 occurs. Since the first group barrel 3 exists in the retracting direction, the one-sided operation is performed. In the one-sided operation, the drive ring 37 is driven to the tele side by a predetermined extra amount from the target stop position. After the first lens barrel 3 is retracted, the driving direction is reversed and the lens is stopped at the target stop position. As a result, the gear train 39
The backlash of .about.45 is removed, and the movement of the first-group lens barrel 3 is prevented even if an input is made to push the first-group lens barrel 3 from outside.

When the zoom operation moves from the tele side to the wide side and the zoom operation is stopped at the extreme tele side between wide and tele, the zoom gear trains 39-4.
Since the backlash of No. 5 exists in the direction in which the first lens barrel 3 is retracted, the one-sided operation is performed. In the one-sided operation, the drive ring 37 is extended by a predetermined amount from the target stop position. The lens is driven to the wide side, the first lens barrel 3 is retracted, and then the driving direction is reversed to stop at the target stop position.

When the zoom operation is shifted from the wide side to the tele side and the zoom operation is stopped at the extreme tele side between wide and tele, the backlash of the gear trains 39 to 45 becomes one group. Because it exists in the direction in which the lens barrel 3 is extended,
No offset operation is required.

Further, when the zoom operation is shifted from the tele side to the wide side and the zoom operation is stopped on the extreme wide side between the wide and the tele, the backlash of the gear trains 39 to 45 is caused by one group. Since it exists in the direction in which the lens barrel 3 is extended, the offset operation is not necessary in this case as well.

In the flowchart shown in FIG. 9, when the zoom operation is started, in step S011, a tele switch T (not shown) for instructing a zoom operation from the wide side to the tele side of the zoom switch 77 is turned on. Alternatively, it is detected whether a wide switch W (not shown) for instructing a zoom operation from the tele side to the wide side has been turned on. When the tele switch T is turned on, the process proceeds to step S012, and when the wide switch TW is turned on, step S01 is performed.
Go to 7.

In step S012, the zoom motor 38 is driven to rotate forward to move the zoom lens to the telephoto side. When the zoom motor 38 rotates forward, FIG.
As shown in (c), the first-group lens barrel 3 moves in the retreating direction toward the extreme value P. Then, step S01
In 3, it is determined whether or not the zoom switch 77 has been turned off, and if it has been turned on, the zoom motor is driven in the same direction,
When the power is turned off, in step S014, the driving of the zoom motor is stopped, and the first lens barrel 3 and the second lens barrel 9 are stopped at that position.

As described above, the position of the first lens barrel 3 is detected by the linear sensor 56 in accordance with the rotation angle of the drive ring 37, and in step S015, step S0 is performed.
It is determined whether the stop position at 14 is between the wide end and the extreme value P.

In step S015, the stop position of the first lens barrel 3 is changed to the extreme value P during driving from the wide end to the telephoto direction.
Between the lens and the telephoto end, it is not necessary to perform the one-sided operation for removing the backlash as described above.
If the stop position is between the extreme value P and the wide end, the offset operation (hysteresis removal operation) for removing backlash is required as described above, and therefore, step S01.
Proceed to 6.

In step S016, an offset operation for removing hysteresis in zoom drive from the wide end to the telephoto direction is performed. This shifting operation is performed by the zoom gear train 3
Since the backlashes 9 to 45 exist in the retraction direction of the first lens barrel 3, the drive ring 37 is driven to the telephoto side (retraction direction) by a predetermined amount more than the target stop position, and the first lens barrel 3 is moved. After the retraction, the zoom motor 38 is rotated in the reverse direction to stop at the target stop position. That is, the stop position of the first lens barrel 3 when the zoom switch 77 is turned off is stored, and the position is returned to the stored position.

As a result, the backlash of the gear trains 39 to 45 is removed, and the movement of the first-group lens barrel 3 is prevented when the first-group lens barrel 3 is inputted so as to be pushed in from the outside.

On the other hand, in step S017, the zoom motor 38 is driven to rotate in the reverse direction to move the zoom lens to the wide side. When the zoom motor 38 rotates in the reverse direction, as shown in FIG. 5C, the first-group lens barrel 3 moves in the retreating direction toward the extreme value P. Then, in step S018, it is determined whether or not the zoom switch 77 has been turned off. If the switch has been turned on, the zoom motor is driven in the same direction. The barrel 3 and the second lens barrel 9 are stopped at that position.

As described above, the position of the first lens barrel 3 is detected by the linear sensor 56 in accordance with the rotation angle of the drive ring 37, and in Step S020, Step S0
It is determined whether the stop position at 19 is between the telephoto end and the extreme value P.

In step S020, the stop position of the first lens barrel 3 becomes the extreme value P during driving in the wide direction from the telephoto end.
If the position is between the extreme end and the wide end, the offsetting operation for removing backlash is not necessary as described above, but the stop position of the first lens barrel 3 is between the extreme value P and the tele end. As described above, a biasing operation (hysteresis removing operation) for removing backlash is required as described above, so that step S01 is performed.
Proceed to 6.

In step S016, an offset operation for removing hysteresis in zoom driving from the telephoto end to the wide direction is performed. This shifting operation is performed by the zoom gear train 3
Since the backlashes 9 to 45 exist in the retraction direction of the first lens barrel 3, the drive ring 37 is driven to the wide side (retraction direction) by a predetermined amount more than the target stop position, and the first lens barrel 3 is moved. After the retraction, the zoom motor 38 is rotated in the forward direction to stop at the target stop position. That is, the stop position of the first lens barrel 3 when the zoom switch 77 is turned off is stored, and the position is returned to the stored position.

As a result, the backlash of the gear trains 39 to 45 is removed, and the movement of the first-group barrel 3 is prevented when the first-group barrel 3 is input to push it in from the outside.

(Correspondence between the Invention and the Embodiment) In the above-described embodiment, the first lens barrel 3 is used for the optical unit of the present invention, the control unit 74 is used for the drive control means or the control means of the present invention, and the linear sensor is used. 56 corresponds to the determination means of the present invention, the zoom switch 77 corresponds to the instruction means of the present invention, and the zoom motor 38 corresponds to the driving means of the present invention.

The above is the correspondence between the components of the present invention and the components of the embodiments. However, the present invention is not limited to the configurations of the embodiments, and the functions described in the claims or It goes without saying that any configuration may be used as long as the function of the configuration of the embodiment can be achieved.

The focal length may be of a bifocal or multifocal switching type.

The optical unit may be other than a lens, for example, a filter.

In the above-described embodiment, the extreme value is convex on the image side, but may be reversed.

Further, the present invention may combine the above-described embodiments and modified examples, or their technical elements as needed.

The present invention is also applicable to various types of cameras such as a single-lens reflex camera, a lens shutter camera, and a video camera.
Furthermore, optical devices and other devices other than cameras, furthermore, those cameras, optical devices, and other devices, and devices applied to those cameras, optical devices, and other devices, or elements that constitute them Can be applied.

The present invention is such that the whole or a part of the configuration of the claims or the embodiment forms one device and is combined with another device. Or it may be something like an element constituting the device.

[0082]

As described above, according to the present invention, the backlash is removed regardless of the position where the optical unit is stopped. The displacement can be prevented.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a zoom lens barrel of a camera according to an embodiment of the present invention.

FIG. 2 is a development view of the fixed cylinder of FIG.

3A and 3B show the barrier opening / closing mechanism of FIG. 1, wherein FIG. 3A shows a closed state and FIG.

FIG. 4 is a perspective view of the drive ring and its drive mechanism of FIG. 1;

5A is a cam locus of the fixed barrel of FIG. 1, FIG. 5B is a cam locus of the moving cam ring and the first lens barrel, and FIG. 5C is a cam locus of the sum of the moving cam ring and the first lens barrel. FIG.

FIG. 6 is an exploded view of the fixed cylinder, the moving cam ring, and the rotating cylinder of FIG. 1;

FIG. 7 is a flowchart of a barrier opening operation of FIG. 1;

FIG. 8 is a control block diagram of the lens barrel in FIG. 1;

FIG. 9 is a flowchart showing a zoom operation of the control unit in FIG. 8;

10A is a development view showing a cam groove of a moving cam ring of a conventional zoom lens, and FIG. 10B is a developed view showing a cam groove of a moving ring to which the present invention is applied.

[Explanation of symbols]

 2 Fixed barrel 3 First lens barrel 37 Drive ring 48 Moving cam ring 54 Barrier

Claims (21)

[Claims] In a variable focal length optical apparatus, a moving direction is changed from one of a feeding direction and a moving direction to the other while changing a focal length from one of a short focal length end and a long focal length end to the other. When it is determined that the optical unit moves in the retraction direction and stops at the stop position based on the changing optical unit that may receive an external force in the retraction direction and the position and the focal length change direction of the optical unit. A drive control means for moving the optical unit in the retraction direction beyond the stop position, and then moving the optical unit in the extension direction to stop at the stop position. 2. The variable focal length optical device according to claim 1, wherein the variable focal length optical device is a camera. 3. The variable focal length optical device according to claim 1, wherein the variable focal length optical device is a lens barrel. 4. The optical unit according to claim 1, wherein the moving direction of the optical unit changes from a retraction direction to a retraction direction while changing the focal length from a short focal length end to a long focal length end. The variable focal length optical device according to any one of the above. 5. The variable focal length optical device according to claim 1, wherein the optical unit forms a zoom optical system. 6. The variable focal length optical device according to claim 1, further comprising a driving unit for changing a focal length. 7. A driving unit, comprising: an instructing unit that instructs the driving unit to change a focal length direction; and a judging unit that determines a focal length position. 7. The variable focal length optical device according to claim 6, wherein the focal length change direction is determined from a focal length change driving direction, and the position of the optical unit is determined from the focal length position determined by the determination unit. 8. The variable focal length optical apparatus according to claim 6, wherein said drive control means controls said drive means. 9. An external force in a retreating direction in which a moving direction changes from one of a dispensing direction and a retreating direction to the other while changing a focal length from one of a short focal length end and a long focal length end to the other. An optical unit that is likely to receive light and a variable focal length optical device applied to a drive unit that drives the optical unit, wherein the control unit controls the drive unit, and the control unit includes the optical unit If it is determined that the optical unit moves in the retraction direction and reaches the stop position based on the position and the focal length change direction, after moving the optical unit in the retraction direction beyond the stop position A variable focal length light having control means for controlling said driving means so as to move in the feeding direction and stop at said stop position. Equipment. 10. The variable focal length optical device according to claim 9, wherein the variable focal length optical device is a camera. 11. The variable focal length optical device according to claim 9, wherein the variable focal length optical device is a lens barrel. 12. The moving direction of the optical system changes from one of the extension direction and the retraction direction to the other while the focal length is changed from one of the short focal length end and the long focal length end to the other. An optical unit that is the foremost part of the optical system, a driving unit that drives the optical unit, and a control unit that controls the driving unit, wherein the control unit controls the position of the optical unit and the focal length changing direction. If it is determined that the optical unit moves in the retracting direction and reaches the stop position based on the optical unit, the optical unit is moved in the retracting direction beyond the stop position and then moved in the extending direction to stop the optical unit. Control means for controlling the driving means so as to stop at a position. 13. The variable focal length optical device according to claim 12, wherein the optical unit is a lens. 14. The variable focal length optical apparatus according to claim 12, wherein said driving means is a motor. 15. An image forming apparatus comprising: an instructing unit for instructing the focal length changing direction; and a judging unit for judging a position of the optical unit. 13. The variable focal length optical device according to claim 12, wherein it is determined whether the optical unit moves in the retraction direction and reaches the stop position. 16. An optical unit comprising: an instructing unit for instructing the focal length changing direction; and a judging unit for judging a focal length state. 13. The variable focal length optical device according to claim 12, wherein it is determined whether or not the lens moves in the retraction direction to reach the stop position. 17. The variable focal length optical device according to claim 12, wherein the variable focal length optical device is a camera. 18. The variable focal length optical device according to claim 12, wherein the variable focal length optical device is a lens barrel. 19. The method according to claim 19, wherein the moving direction of the optical system changes from one of the extension direction and the retraction direction to the other while the focal length is changed from one of the short focal length end and the long focal length end to the other. The forefront optical unit that constitutes the optical system, and, in the focal length variable optical device applied to the drive unit that drives the optical unit, the control unit that controls the drive unit, the control unit,
If it is determined that the optical unit moves in the retraction direction and reaches the stop position based on the position of the optical unit and the focal length change direction, the optical unit is moved in the retraction direction beyond the stop position. A focal length variable optical device, comprising: control means for controlling the driving means so as to move in the extension direction after the movement and stop at the stop position. 20. The variable focal length optical device according to claim 19, wherein the variable focal length optical device is a camera. 21. The variable focal length optical device according to claim 19, wherein the variable focal length optical device is a lens barrel.