JP2016133568A - Zoom lens barrel and optical apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens barrel capable of preventing defective lock caused by abrasion with a mechanism for suppressing driving of a zoom mechanism.SOLUTION: A zoom lens barrel 10 includes a zoom ring 18 for performing zooming by receiving predetermined zooming operation and a lock changeover mechanism 20 for performing changeover between a lock state for suppressing driving of the zoom ring 18 by electromagnetic force and a lock release state for suppressing no driving of the zoom ring 18.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a zoom lens barrel and an optical apparatus.

  2. Description of the Related Art Conventionally, a zoom lens barrel that includes a plurality of lens groups and performs zooming by receiving a predetermined zooming operation (for example, a user operation for rotating a zooming operation ring) has been widely used. Such a zoom lens barrel, particularly a high-power zoom lens barrel, is hung from the shoulder or neck by a strap attached to the camera body with the zoom lens barrel mounted on the camera body, for example. When carrying the camera, the zoom mechanism may be driven by its own weight and the zoom lens barrel may be extended. In this way, if the zoom lens barrel extends without the photographer being aware of it, the lens barrel may be damaged due to collision with an obstacle.

  In order to prevent such an extension of the zoom lens barrel due to its own weight, for example, Patent Document 1 discloses a zoom lens barrel including a fixed barrel and a movable barrel movable in the optical axis direction with respect to the fixed barrel. A zoom lens barrel that can lock the movement of the movable cylinder relative to the fixed cylinder by providing a notch in the movable cylinder and engaging a lock member provided on the fixed cylinder in the notch is disclosed. Has been.

JP-A-10-104495

  Here, in the invention described in Patent Document 1, the movement of the movable cylinder with respect to the fixed cylinder is mechanically locked by engaging the lock member with the notch. For this reason, the lock member and the notch are worn. When this occurs, there is a problem that it becomes impossible to lock firmly.

  Further, in the invention described in Patent Document 1, it is only possible to lock the movement of the movable cylinder with respect to the fixed cylinder at the wide-angle end (that is, the state in which the lens barrel is most contracted). At the time of telephoto, the movement of the movable cylinder relative to the fixed cylinder could not be locked.

  The present invention has been made in view of the above-described demand, and an object of the present invention is to provide a zoom lens barrel that can prevent a lock failure due to wear or the like in a mechanism for suppressing the driving of the zoom mechanism.

  The zoom lens barrel of the present invention is a lock that switches between a zoom mechanism that receives a predetermined zooming operation and performs zooming, and a locked state that suppresses driving of the zoom mechanism by electromagnetic force and an unlocked state that does not suppress driving of the zoom mechanism. And a switching mechanism.

  According to the present invention, the lock switching mechanism can switch between the locked state and the unlocked state of the zoom mechanism using electromagnetic force. In addition to preventing defects, it is possible to prevent the zoom mechanism from being driven at a timing not intended by the user in the locked state. Further, according to the present invention, since the lock state and the unlock state can be switched by electromagnetic force, the zoom mechanism can be locked in a desired telephoto state.

In the present invention, the lock switching mechanism preferably includes a coil and a magnet, and switches between the locked state and the unlocked state depending on whether the coil is in a short-circuited state or an open state.
According to the present invention having such a configuration, the zoom mechanism can be switched between the locked state and the unlocked state by switching the coil between the short-circuited state and the opened state, and the zoom mechanism can be locked without requiring power. can do.

In the present invention, it is preferable that the lock switching mechanism sets the zoom mechanism in a locked state in a short circuit state.
According to the present invention having such a configuration, the zoom mechanism can be locked because the short brake state occurs when the coil is short-circuited.

In the present invention, it is preferable that the lock switching mechanism locks the zoom mechanism by a counter electromotive force generated in the coil in a short circuit state.
According to the present invention having such a configuration, by switching to the short circuit state, a back electromotive force is generated in the coil due to the magnetic field of the coil, so that the zoom mechanism can be prevented from being driven, and the open state can be achieved. Since no back electromotive force is generated by switching to, the unlocked state in which the driving of the zoom mechanism is not suppressed can be achieved.

In the present invention, the lock switching mechanism is preferably a motor including a coil and a magnet.
According to the present invention having such a configuration, since the driving of the zoom mechanism can be suppressed by setting the motor to a short state, a power source or the like is not required.

In the present invention, the motor is preferably a brushless motor.
According to the present invention having such a configuration, the brushless motor can change the resistance force against the rotation of the rotating shaft of the motor to a desired value. For example, the resistance force can be adjusted according to the operation of the zoom mechanism. Thus, the resistance to the zoom operation can be made constant and a better operational feeling can be provided.

In the present invention, the lock switching mechanism preferably switches between the locked state and the unlocked state depending on whether the lock switching mechanism is in an energized state or a non-energized state.
According to the present invention having such a configuration, it is possible to switch between the locked state and the unlocked state according to the energized state or the non-energized state.

In the present invention, it is preferable that the lock switching mechanism locks the zoom mechanism in a non-energized state.
In many cases, the lock switching mechanism is brought into a locked state when an optical device such as a zoom lens barrel and a camera is not driven, such as during movement. On the other hand, according to the present invention having such a configuration, when the lock switching mechanism is brought into the unlocked state, optical devices such as a zoom lens barrel and a camera are driven, and these power sources are used. Therefore, it is not necessary to provide a new power source. In addition, since the lock switching mechanism is energized only when the optical apparatus is used, the necessary power can be suppressed.

In the present invention, the lock switching mechanism has a fluid whose viscosity changes between an energized state and a non-energized state, and changes the viscosity of the fluid between the energized state and the non-energized state, thereby locking and unlocking It is preferable to switch between states.
According to the present invention having such a configuration, since the viscosity of the fluid is changed between the energized state and the non-energized state, the locked state and the unlocked state are switched, so that problems such as member wear can be avoided. .

In the present invention, the fluid preferably has a low viscosity in the energized state and a high viscosity in the non-energized state. In the present invention, the fluid is preferably an MR fluid.
According to the present invention having such a configuration, the viscosity of the fluid is increased in a non-energized state and can be brought into a locked state, so that the locked state can be obtained without requiring electric power. Moreover, it is not necessary to provide a new power source.

  The optical apparatus of the present invention includes the zoom lens barrel described above.

  ADVANTAGE OF THE INVENTION According to this invention, the zoom lens barrel which can prevent the lock failure by abrasion etc. in the mechanism for suppressing the drive of a zoom mechanism can be provided.

The structure of the single-lens reflex camera by 1st Embodiment of this invention is shown, and the state at the time of a wide angle is shown. The structure of the single-lens reflex camera by 1st Embodiment of this invention is shown, and the state at the time of telephoto is shown. 1 shows a configuration of a zoom lens barrel lock switching mechanism according to a first embodiment of the present invention, showing a locked state; The structure of the lock switching mechanism of the zoom lens barrel according to the first embodiment of the present invention is shown, and the unlocked state is shown. The modification of the structure of the lock | rock switching mechanism of the zoom lens barrel by 1st Embodiment of this invention is shown, and a lock release state is shown. The structure of the lock switching mechanism of the zoom lens barrel according to the second embodiment of the present invention is shown, and the unlocked state is shown. It is a figure which shows the structure of the lock switching mechanism of the zoom lens barrel by 3rd Embodiment of this invention, and shows a lock release state.

<Embodiment 1>
Hereinafter, a zoom lens barrel and an optical apparatus according to a first embodiment of the present invention will be described in detail with reference to the drawings. In the following description, a case where the present invention is applied to a single-lens reflex camera as an optical device will be described.

  1 and 2 show the configuration of the single-lens reflex camera 1 according to the present embodiment. FIG. 1 shows a wide angle view and FIG. 2 shows a telephoto view. As shown in FIGS. 1 and 2, the single-lens reflex camera 1 of the working gas is configured by mounting a zoom lens barrel 10 on a camera body 2 having an image sensor.

  The zoom lens barrel 10 is, for example, a high-magnification telephoto lens having a focal length of 16 to 300 mm, a fixed cylinder 12 connected to the camera body via a mount, and a first moving cylinder accommodated in the fixed cylinder 12. 14 and a second moving cylinder 16 accommodated in the first moving cylinder 14. One or a plurality of lens groups (not shown) are respectively held inside the fixed cylinder 12, the first moving cylinder 14, and the second moving cylinder 16 via an attachment frame.

  The zoom lens barrel 10 has an annular zoom ring 18 (zoom mechanism) attached to the outer periphery of the fixed cylinder 12 and a cam mechanism linked to the zoom ring 18. When the photographer rotates the zoom ring 18 in a predetermined direction with respect to the fixed cylinder 12, the first moving cylinder 14 is extended in the optical axis direction with respect to the fixed cylinder 12 by the cam mechanism and the second movement. The cylinder 16 is drawn out with respect to the first moving cylinder 14, and the entire length of the lens barrel is increased. Along with the movement of the first moving cylinder 14 and the second moving cylinder 16, the positional relationship of each lens group is changed to change from the wide angle state to the telephoto state.

  Further, by rotating the zoom ring 18 in a direction opposite to the predetermined direction with respect to the fixed cylinder 12, the first moving cylinder 14 is retracted toward the fixed cylinder 12 by the cam mechanism, and the second moving cylinder 16 retreats toward the first moving cylinder 14, and the total length of the lens barrel is shortened. As the first moving cylinder 14 and the second moving cylinder 16 move, the positional relationship between the lens groups is changed, and the telephoto state is changed to the wide-angle state. That is, the zoom lens barrel 10 of the present embodiment can perform zooming (optical zooming) by performing a predetermined zooming operation (rotation operation) on the zoom ring 18.

  A conventionally known mechanism can be adopted as the cam mechanism for moving the first moving cylinder 14 and the second moving cylinder 16 forward and backward with respect to the fixed cylinder 12. In this embodiment, a zoom lens barrel having two moving cylinders will be described. However, the present invention is not limited to this, and the present invention is also applied to a zoom lens barrel having one or three or more moving cylinders. it can. In the present embodiment, the configuration in which the entire length of the lens barrel is increased when the wide-angle state is changed to the telephoto state is described as an example, but the present invention is not limited to this. For example, when changing from the wide angle state to the telephoto state, the total length of the lens barrel may be shortened. When changing from the wide angle state to the telephoto state, the total length of the lens barrel is not changed. It may be.

  Furthermore, the zoom lens barrel 10 of the present embodiment has a self-weight of the zoom lens barrel 10 (more specifically, the first moving cylinder 14, the lens group held by the first moving cylinder 14, and the second A lock switching mechanism 20 is provided for preventing expansion and contraction due to the moving cylinder 16 and the lens group held by the first moving cylinder 16. 3 and 4 are diagrams showing the configuration of the lock switching mechanism 20 in the zoom lens barrel 10 of the present embodiment. FIG. 3 shows a locked state, and FIG. 4 shows a unlocked state. As shown in FIGS. 3 and 4, the lock switching mechanism 20 includes a circuit 24 including a motor 22 and a switch 26, a first gear 30 attached to a rotating shaft 22 </ b> A of the motor motor 22, and a first gear 30. A second gear 32 that meshes with the second gear 32, a third gear 36 that is connected to the second gear 32 via the shaft 34, and an internal gear that is attached to the inside of the zoom ring 18 and meshes with the third gear 36. 38. The first gear 30 has fewer teeth than the second gear 32, and the first gear 30 and the second gear 32 constitute a speed reducer 28. With this configuration, the rotational force of the zoom ring 18 is transmitted to the rotational shaft 22A of the motor 22 via the speed reducer 28, and the resistance force to the rotational force generated on the rotational shaft 22A of the motor 22 is transmitted via the speed reducer 28. Is transmitted to the zoom ring 18.

  In the present embodiment, a small DC motor is used as the motor 22. The motor 22 includes a coil 22C connected to the rotating shaft 22A and a magnet 22B disposed around the coil 22C. The circuit 24 includes a switch 26, and electric wires extending from both poles of the switch 26 are connected to a pair of brushes 22 </ b> D of the motor 22. The coil 22C is connected to a pair of commutators 22E, and when the coil 22C rotates, each commutator 22E alternately contacts the pair of brushes 22D.

  As shown in FIG. 3, by closing the switch 26 (by turning on the switch), the circuit 24 is short-circuited, and the motor, that is, the coil 22C is short-circuited. At this time, if the zoom ring 18 tries to rotate, and the coil 22C of the motor 22 tries to rotate in the magnetic field generated by the magnet 22B, the magnetic flux changes in the coil 22C. When the magnetic flux changes in the coil 22C as described above, a back electromotive force is generated by electromagnetic induction. This counter electromotive force generates a force that prevents rotation in a direction opposite to the direction in which the coil 22C is used for rotation, and acts as a braking force (hereinafter, such a brake is referred to as a short brake). Thus, when the switch 26 is closed, a braking force is applied to the rotating shaft 22A of the motor 22, and the rotating shaft 22A cannot rotate unless a force greater than a predetermined rotating force is applied. The braking force generated on the rotating shaft 22 </ b> A of the motor 22 is transmitted to the zoom ring 18 via the speed reducer 28. As described above, the lock switching mechanism 20 is switched to the locked state in which the driving of the zoom mechanism is suppressed by setting the switch 26 in the closed state, that is, setting the lock switching mechanism 20 in the short-circuit state. The driving of the zoom mechanism includes not only the movement of the zoom mechanism by its own weight but also the operation of the zoom mechanism by a zooming operation by the user and the movement of the zoom mechanism by vibration.

  As shown in FIG. 4, by opening the switch 26 (by turning the switch OFF), the coil 22C also becomes an open motor and the short brake is released. Thereby, the rotating shaft 22A of the motor 22 can rotate with almost no load acting thereon. Thus, by opening the switch 26, the zoom ring 18 is in a state (unlocked state) in which the zoom ring 18 can be rotated without being restrained from being driven.

  In the present embodiment, switching of the switch 26 between ON and OFF, that is, switching between the locked state and the unlocked state of the lock switching mechanism 20 is specifically a zoom lock operation provided on the exterior of the lens. This is realized by a switch (hereinafter also simply referred to as “operation switch”). For example, when the operation switch is turned on, the lock switching mechanism 20 is in the locked state, and when the operation switch is turned off, the lock switching mechanism 20 is in the unlocked state.

  As will be described later, for example, when the single-lens reflex camera 1 is placed in such a posture that the zoom lens barrel 10 faces upward or downward, a rotational force acts on the zoom ring 18 due to the weight of the movable barrels 14 and 16. . The gear ratio of the reduction gear 28 is amplified by the reduction gear 28 and transmitted to the zoom ring 18. The resistance force generated on the rotating shaft 22 </ b> A of the motor 22 in the short brake state is generated by the weight of the moving cylinders 14 and 16. It is set to be larger than the rotational force.

  Hereinafter, in the single-lens reflex camera 1 described above, a method of locking expansion / contraction of the zoom lens barrel 10 when the single-lens reflex camera 1 is carried with the zoom lens barrel 10 zoomed in a desired telephoto state will be described. .

  During normal use, the switch 26 is opened as described with reference to FIG. As described above, when the switch 26 is opened, the short brake is released for the motor 22, and the rotating shaft 22A of the motor 22 can rotate with almost no load acting thereon. By rotating the zoom ring 18 in this state, the first moving cylinder 14 and the second moving cylinder 16 move forward or backward with respect to the fixed cylinder 12 and can be zoomed to a desired telephoto state.

  Next, when locking in a zoomed state in a desired telephoto state, the switch 26 is closed as described with reference to FIG. As described above, by closing the switch 26, the motor 22 enters a short brake state, and resistance force acts when the rotary shaft 22A is to be rotated. This resistance force is increased by the speed reducer 28 and transmitted to the zoom ring 18.

  For this reason, for example, the single-lens reflex camera 1 is in a state in which the zoom lens barrel 10 faces downward, and the rotating force acts on the zoom ring 18 by the weights of the first moving cylinder 14 and the second moving cylinder 16. Even so, the zoom ring 18 is prevented from rotating by the above-described resistance. Thereby, it is possible to prevent the zoom lens barrel 10 from extending due to the weight of the first moving cylinder 14 and the second moving cylinder 16.

  Further, even when the single lens reflex camera 1 is in a state where the zoom lens barrel 10 faces upward, similarly, since the resistance force is transmitted to the zoom ring 18, the zoom lens barrel 10 It is possible to prevent the first moving cylinder 14 and the second moving cylinder 16 from contracting due to their own weight.

  Even when the switch 26 is closed in this way, it is possible to perform a zooming operation by applying a rotational force larger than the resistance force of the motor 22 to the zoom ring 18.

  As described above, according to the single-lens reflex camera 1 of the present embodiment, when the coil 22C of the motor 22 is opened by opening the switch 26, the motor 22 is in a state where the short brake is released. Although no resistance force acts on the zoom ring 18, when the coil 22C of the motor 22 is short-circuited by closing the switch 26, a resistance force acts on the zoom ring 18 due to the short brake. To do. For this reason, even when the zoom lens barrel 10 is in the desired telephoto state, the single-lens reflex camera 1 is directed upward or downward and zoomed by the weight of the first moving cylinder 14 and the second moving cylinder 16. Even if a rotational force acts on the ring 18, the zoom ring 18 is prevented from rotating due to a resistance force generated by closing the switch 26. Thereby, it is possible to prevent the first moving cylinder 14 and the second moving cylinder 16 from moving with respect to the fixed cylinder 12 with the zoom lens barrel 10 in a desired telephoto state.

  In the present embodiment, a load is applied to the zoom ring 18 by electromagnetic force by short-circuiting the coil 22C of the motor 22. Therefore, mechanical deterioration such as wear does not occur in the lock switching mechanism, and it is possible to prevent a lock failure and to prevent the zoom ring 18 from being driven at a timing not intended by the user in the locked state.

  Further, in the present embodiment, since the load is applied to the zoom ring 18 by putting the motor 22 in the short brake state, the driving of the zoom ring 18 can be suppressed without requiring electric power.

  Furthermore, in this embodiment, since the rotation of the zoom ring 18 is not mechanically fixed and a resistance force is applied by a short brake of the motor 22, a large force is applied to the zoom ring 18 even in the locked state. Zoom operation is possible. This is due to the weight of the zoom lens barrel 10 even when shooting with the camera facing upward, such as when shooting with the camera facing upward, or when shooting with the camera pointing downward, such as when shooting from below. This is effective because the telephoto state does not change.

  In addition, the single-lens reflex camera of this invention is not limited to said embodiment. For example, a brushless motor can be used as the motor. Thus, by using a brushless motor as the motor 22, the resistance force against the rotation of the rotating shaft 22A of the motor 22 can be changed to a desired value.

  Normally, in a zoom lens barrel having a plurality of lens groups, a plurality of moving cylinders are driven with respect to the fixed cylinder so that the rotation of the zoom ring 18 and the magnification are in a substantially proportional relationship. However, the positional relationship between the magnification and the plurality of fixed cylinders is not necessarily a proportional relationship, and the relationship between the rotation angle of the zoom ring and the moving distance of the movable cylinder differs between the telephoto state and the wide angle state. For this reason, the conventional zoom lens barrel has a problem that the resistance to the rotation operation when rotating the zoom ring is different between the telephoto state and the wide-angle state.

  On the other hand, if a brushless motor is used as the motor 22, the resistance force against the rotation of the rotating shaft 22A of the motor 22 can be changed to a desired value, so that the resistance force is adjusted according to the rotation of the zoom ring. Thus, for example, it is possible to make the resistance against the rotation operation applied to the zoom ring 18 constant and provide a better operational feeling.

  In the present embodiment, in the unlocked state, the switch 26 is only opened and the short brake of the motor 22 is released. For example, as shown in FIG. 5, the first gear 30 and the second gear The meshing with the gear 32 may be released. In this case, the switch 26 does not need to be opened.

  In the first embodiment, the case where a motor incorporating a coil and a magnet is used has been described. However, regardless of this, the coil and the magnet are arranged at appropriate positions, and the magnet is in a short-circuited state. The back electromotive force may be generated in the circuit connected to the coil by the magnetic field.

<Embodiment 2>
Further, the mechanism for switching between the locked state and the unlocked state of the zoom mechanism is not limited to a motor, and any mechanism that can switch between a state that suppresses driving of the zoom mechanism and a state that does not suppress driving of the zoom mechanism may be used. A fluid whose viscosity changes between an energized state and a non-energized state such as an MR fluid can be used. Hereinafter, a second embodiment in which MR fluid is used as a mechanism for suppressing the driving of the zoom mechanism will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 6 shows the structure of the zoom lens barrel 110 of the second embodiment, the structure of the lock switching mechanism, and shows the unlocked state. As shown in FIG. 6, the lock switching mechanism 24 included in the zoom lens barrel 110 of the second embodiment is provided with a load applying device 122 instead of the motor 22 of the first embodiment, and is added to the circuit 124 in addition to the switch 126. This is different from the first embodiment in that a power supply 127 is provided. The power source 127 can also serve as a power source for driving a motor for focusing the lens.

  The load applying device 122 includes a housing 122D, an MR fluid 122E filled in the housing 122D, a rotating shaft 122A, a plurality of blade-like members 122B attached to the rotating shaft 122A, and a pair provided in the housing 122D. Electrode 122C.

  An opening is formed in the housing 122D, and one end of the rotating shaft 122A protrudes outward of the housing 122D through this opening. A first gear 30 is attached to an end portion that protrudes to the outside of the rotating shaft 122A.

  The plurality of blade-like members 122B are plate-like members, and are attached to the outer periphery of the portion of the rotating shaft 122A within the housing 122D with a predetermined angular interval. The number and size of the blade-like member 122B may be set according to the load necessary to lock the zooming operation, and is not particularly limited.

  An electric wire extending from the switch 126 is connected to one electrode 122C of the load applying device 122, and an electrode extending from the power source 127 is connected to the other electrode 122C. By closing the switch 126, a potential difference is generated between the pair of electrodes 122C, and a magnetic field is generated.

  The MR fluid 122E is a fluid containing magnetic fine particles. In the state where the magnetic force is not applied to the MR fluid 122E, the magnetic fine particles are attracted to each other and are randomly bonded, but the viscosity is high, but when the magnetic force is applied, the magnetic fine particles are aligned in a certain direction, It is a fluid with low resistance (viscosity).

  In order to lock the load applying device 122, the switch 126 of the circuit 124 is opened. As a result, the load applying device 122 is de-energized, and no magnetic force acts in the housing 122D. For this reason, when trying to rotate the rotating shaft 122A of the load applying device 122, a resistance force acts on the blade-like member 122B due to the viscosity of the MR fluid 122E. Thereby, in a state where the switch 126 is opened, the rotating shaft 122A of the load applying device 122 cannot be rotated unless a force greater than a predetermined rotational force is applied. The resistance force generated on the rotating shaft 122 </ b> A of the load applying device 122 is transmitted to the zoom ring 18 via the speed reducer 28. Thus, when the switch 126 is in the closed state, that is, when the lock switching mechanism 24 is in the energized state, the lock switching mechanism 24 is in the locked state that suppresses the driving of the zoom mechanism.

  On the other hand, in order to bring the load applying device 122 into the unlocked state, the switch of the circuit 124 is closed. As a result, the load applying device 122 is de-energized and a magnetic field is generated in the housing 122D. Thus, when a magnetic field is generated in the housing 122D, even if the blade-like member 122B rotates about the rotation shaft 122A, the resistance force by the MR fluid 122E hardly acts on the blade-like member 122B. Thereby, the rotating shaft 122A of the load applying device 122 can rotate with almost no load acting thereon. Thus, when the switch 126 is in an open state, that is, when the lock switching mechanism 24 is in a non-energized state, the lock switching mechanism 24 enters a lock release state that does not suppress the driving of the zoom mechanism.

  In the present embodiment, the case where the MR fluid is used has been described. However, the present invention is not limited to this, and any fluid may be used as long as the viscosity changes between an energized state and a non-energized state.

According to the second embodiment, the same effect as the first embodiment can be obtained.
In addition, since the lock switching mechanism of the second embodiment is also in a locked state when not energized, a power source such as a motor for focusing the lens can be shared as a power source for unlocking. There is no need to provide a power supply.
In the second embodiment, since the viscosity of the MR fluid 122E is changed between the energized state and the non-energized state, the locked state and the unlocked state are switched, so that problems such as member wear can be avoided.

<Embodiment 3>
In the first and second embodiments, the case where zooming is performed by rotating the zoom ring 18 has been described. However, the present invention is not limited to such an embodiment.

  FIG. 7 is a diagram showing the configuration of the lock switching mechanism of the zoom lens barrel 210 according to the third embodiment of the present invention, and shows the unlocked state. In the zoom lens barrel 210 according to the third embodiment, the positional relationship between the lens groups is changed by an operation of pulling the movable barrel 214 toward the subject side or pushing it toward the imaging side while holding the fixed barrel 212. The wide-angle state is changed to the telephoto state. In other words, the zoom lens barrel 210 of the present embodiment can perform zooming (optical zooming) by expanding and contracting the movable barrel 214 in the optical axis direction.

  As in the first embodiment, the lock switching mechanism 220 of the zoom lens barrel 210 of the present embodiment includes a circuit 24 including the motor 22, a first gear 30 attached to the rotating shaft 22A of the motor 22, and a first gear 30. A second gear 32 that meshes with the first gear 30, and a third gear 36 that is connected to the second gear 32 via a shaft 34. Further, in the lock switching mechanism 220 of the zoom lens barrel 210 of the third embodiment, the pinion 238 is provided on the outer peripheral surface of the moving cylinder 214, and the third gear 36 is engaged with the pinion 238. Also in this embodiment, the first gear 30 has a smaller number of teeth than the second gear 32, and the first gear 30 and the second gear 32 constitute a speed reducer 28.

  Also in this embodiment, the motor 22 is energized by closing the switch 26, and the rotating shaft 22A is in a short brake state in which a resistance force against a rotational force acting from the outside is generated. This resistance force is amplified by the speed reducer 28 and transmitted from the third gear 36 to the pinion 238. Therefore, by closing the switch 26, even if the moving cylinder 214 is moved toward the subject side or the imaging side with respect to the fixed cylinder 212, the moving cylinder 214 is moved unless a force of a predetermined magnitude or more is applied. In other words, the zoom mechanism cannot be driven.

  Further, by opening the switch 26, the motor 22 is de-energized and the short brake is released. Therefore, by opening the switch 26, the movable cylinder 214 can be easily moved to the subject side or the imaging side with respect to the fixed cylinder 212, that is, the unlocking state in which the driving of the zoom mechanism is not suppressed. It can be.

  In the present embodiment, the case where the present invention is applied to a single-lens reflex camera has been described. However, the present invention is not limited thereto, and the present invention is applicable to any optical apparatus including a zoom lens barrel such as a mirrorless camera or a video camera. Can be applied.

1 single-lens reflex camera 2 camera body 10, 110, 210 zoom lens barrel 12, 212 fixed barrel 14 first moving barrel 16 second moving barrel 18 zoom ring 20, 220 lock switching mechanism 22 motor 22A rotating shaft 22B magnet 22C Coil 22D Brush 22E Commutator 24, 124 Circuit 26, 126 Switch 28 Reduction gear 30 First gear 32 Second gear 34 Shaft 36 Third gear 38 Internal gear 122 Load applying device 122A Rotating shaft 122B Blade-like member 122C Electrode 122D Housing 122E MR fluid 127 Power source 214 Moving cylinder 238 Pinion

Claims (12)

A zoom mechanism that accepts a predetermined zooming operation and performs zooming;
A lock switching mechanism that switches between a locked state that suppresses driving of the zoom mechanism by electromagnetic force and a unlocked state that does not suppress driving of the zoom mechanism;
A zoom lens barrel characterized by comprising: The lock switching mechanism includes a coil and a magnet,
Switching between the locked state and the unlocked state depending on whether the coil is in a short circuit state or an open state,
The zoom lens barrel according to claim 1. The lock switching mechanism sets the zoom mechanism to the locked state in a short-circuit state.
The zoom lens barrel according to claim 2. The lock switching mechanism causes the zoom mechanism to be in the locked state by a counter electromotive force generated in the coil in a short circuit state.
The zoom lens barrel according to claim 3. The lock switching mechanism is a motor including the coil and the magnet.
The zoom lens barrel according to any one of claims 2 to 4. The motor is a brushless motor,
The zoom lens barrel according to claim 5. The lock switching mechanism switches between the locked state and the unlocked state depending on whether the lock switching mechanism is in an energized state or a non-energized state.
The zoom lens barrel according to claim 1. The lock switching mechanism is
The zoom mechanism is in the locked state in a non-energized state,
The zoom lens barrel according to claim 7. The lock switching mechanism is
It has a fluid whose viscosity changes between an energized state and a non-energized state,
By switching the viscosity of the fluid between an energized state and a non-energized state, the locked state and the unlocked state are switched.
The zoom lens barrel according to claim 3. The fluid is
Viscosity decreases when energized,
Viscosity increases in a non-energized state,
The zoom lens barrel according to claim 9. The fluid is an MR fluid;
The zoom lens barrel according to claim 9 or 10.   An optical apparatus including the zoom lens barrel according to any one of claims 1 to 11.

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