JP2015004759A - Lens device and imaging apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a variable power operation in a photographing region silent.SOLUTION: A collapsible lens device storing a photographing optical system forming the optical image of an object and having a variable power function includes a DC motor 100, a driven cam ring 600 rotationally driven by the DC motor, to achieve the displacement between a collapsed state and an extended state and achieve the variable power function, and a gear train transmitting the driving force of the DC motor to the driven cam ring. The gear ratio of the final stage of the gear train in the photographing region from the wide-angle end to the telephoto end of the photographing optical system is smaller than the gear ratio of the gear train in the collapsed state.

Description

  The present invention relates to a lens device and an imaging device having the lens device.

  Patent Document 1 discloses a lens barrel that projects and retracts a lens holding frame by transmitting the driving force of a motor to a large gear portion provided on the outer periphery of the cam ring and rotating the cam ring.

JP 2002-350706 A

  As in Patent Document 1, in a retractable lens barrel that transmits the driving force of a motor via a reduction gear train, noises such as a rotating sound of a motor and a meshing sound of rotating gears become a problem. Especially in recent years, the increase in weight due to high magnification and widening of the angle and the compact design of the lens barrel are required, so the motor load has increased and the gear ratio has been increased by using multiple gears. The problem has become prominent. In order to reduce noise, it is conceivable to increase the motor voltage during high-speed driving and decrease the motor voltage during silent driving. However, when the drive load from the retracted state to the shooting area is large, the gear ratio is determined by the load, so the high gear ratio determined in the non-shooting area is also applied to the shooting area even if the low-speed operation is performed. Will be. As a result, the rotation speed of the actuator does not decrease, and the silent effect by this method is not sufficient.

  It is an exemplary object of the present invention to provide a lens device and an imaging device capable of reducing the magnification change operation in the imaging region.

  The lens apparatus of the present invention is a collapsible lens apparatus that houses a photographic optical system that forms an optical image of a subject and has a zooming function, and is driven to rotate by the driving means. A driving member that realizes a displacement between the retracted state and the extended state and that realizes the zooming function; and a gear train that transmits a driving force of the driving means to the driven member. The gear ratio of the last stage of the gear train in the imaging region from the wide angle end to the telephoto end of the system is smaller than the gear ratio of the gear train in the retracted state.

  ADVANTAGE OF THE INVENTION According to this invention, the lens apparatus and imaging device which can silence the zooming operation in an imaging | photography area | region can be provided.

It is sectional drawing when the lens-barrel of this embodiment exists in a retracted state. It is sectional drawing when the lens barrel shown in FIG. 1 exists in the wide-angle end of an imaging | photography area | region. FIG. 2 is a cross-sectional view when the lens barrel shown in FIG. 1 is at a telephoto end of an imaging region. It is a perspective view which shows the relationship between the drive cam ring and gear unit shown in FIG. FIG. 5 is a development view of the first group cam groove shown in FIG. FIG. 2 is a block diagram of control related to the extension of the lens barrel shown in FIG. 1. It is a top view which shows the engagement state of a gear when the lens-barrel shown in FIG. 1 exists in a retracted state. It is a top view which shows the engagement state of a gear when the lens-barrel shown in FIG. 1 exists in a non imaging | photography area | region. It is a top view which shows the engagement state of a gear when the lens-barrel shown in FIG. 1 exists in a wide angle state. It is a graph which shows the torque required for extending | stretching of the lens-barrel shown in FIG. It is a graph which shows the rotation speed of the DC motor shown in FIG. 1, and the magnitude of noise.

  The lens barrel (lens device) of the present embodiment is a retractable lens barrel that houses a photographing optical system that forms an optical image of a subject and can be displaced between a retracted state and a extended state. The lens barrel has a zoom function. The lens barrel is fixed to a camera body (imaging apparatus body) that houses an image sensor that photoelectrically converts an optical image formed by the photographing optical system. The image pickup apparatus of the present invention can be applied to a digital still camera, a digital video camera, or the like having a retractable lens barrel.

  1 is a cross-sectional view of the lens barrel (lens device) of the present embodiment in a retracted state, and FIG. 2 is a cross-sectional view of the lens barrel of the present embodiment in the extended state at the wide-angle end (WIDE end). FIG. 3 is a cross-sectional view when the lens barrel of this embodiment is at the telephoto end (TELE end) in the extended state. An optical axis Oa of the photographing optical system is indicated by a one-dot chain line.

  The photographing optical system has a four-group configuration including a first lens group L1, a second lens group L2, a third lens group L3, a fourth lens group L4, and an aperture, but the number of lens groups is not limited. The third lens unit L3 is a correction lens that moves in a plane perpendicular to the optical axis Oa to perform image blur correction. The fourth lens unit L4 moves in the optical axis direction to perform a focusing operation (focus). This is a fourth lens group to be performed.

  Reference numeral 1 denotes a first group lens barrel unit (lens holding member) that holds the first lens group L1. Reference numeral 2 denotes a second group lens barrel that holds the second lens group L2. The first group lens barrel unit 1 and the second group lens barrel 2 move between the retracted state and the extended state when a driving cam ring 600 (described later) is driven to rotate, and realize the above zooming function.

  Reference numeral 3 denotes an image blur correction unit that moves the third lens unit L3. Reference numeral 4 denotes a fourth group lens barrel that holds the fourth lens group L4. Reference numeral 5 denotes an aperture shutter unit that adjusts the amount of light. Reference numeral 11 denotes a rear lens barrel to which an image pickup device such as a CCD is attached. Reference numeral 12 denotes a fixed cylinder, which is fixed to the rear lens barrel 11 with three screws.

  Reference numeral 600 denotes a drive cam ring (driven member) that is rotationally driven by a DC motor 100 to be described later. Held possible. The drive cam ring 600 includes a first group cam groove 601, an impact receiving cam groove 602, a second group cam groove 603, a third group cam groove 604, and an aperture shutter cam groove 605.

  The first group cam groove 601 is formed on the outer peripheral wall of the drive cam ring 600 to guide and drive the first lens group L1 in the optical axis direction to guide the displacement between the retracted state and the extended state. It is shown in (b). The second group cam groove 603 is formed on the inner peripheral wall of the drive cam ring 600 to guide and drive the second lens group L2. The third group cam groove 604 is formed on the inner peripheral wall of the drive cam ring 600 to guide and drive the third lens group L3 in the optical axis direction. The aperture shutter cam groove 605 is formed to guide and drive the aperture shutter unit 5 in the optical axis direction.

  The drive cam ring 600 is fitted to a cam follower pin provided integrally with each moving lens group described later. Then, by rotating around the outer diameter of the fixed cylinder 12, the first, second, and third lens groups L1, L2, and L3 and the aperture shutter unit 5 are moved back and forth in the optical axis direction to perform a zooming operation (zooming operation). And the entire lens barrel is retracted.

  Reference numeral 14 denotes a support frame fixed to the rear lens barrel 11 with three screws. A focus motor 15 moves the fourth lens unit L4 in the optical axis direction to perform a focusing operation. The focus motor 15 has a lead screw coaxial with the rotating rotor meshed with a rack 35 attached to the fourth group lens barrel 4, and moves the fourth lens group L4 by the rotation of the rotor. Further, the backlash of each of the fourth group lens barrel 4, the guide bar (not shown), the rack 35, and the lead screw is offset by a torsion coil spring (not shown). The focus motor 15 is fixed to the support frame 14 with two screws.

  The driving means for rotating the drive cam ring 600 is a DC motor 100 as a zoom motor not shown in FIGS. 1 to 3, and the zooming operation is performed by rotating the drive cam ring 600 with a gear train described later. Let it be done. The DC motor 100 is fixed to the rear lens barrel 11 with three screws.

  The position of the fourth group lens barrel 4 is detected using a photo interrupter (not shown). The photo interrupter electrically detects the switching between light shielding and light transmission due to movement of the light shielding part 610 formed in the fourth group lens barrel in the optical axis direction, and detects the reference position of the fourth lens group L4. The zoom (zoom position) reset switch also uses a photo interrupter (not shown) to electrically switch between light shielding and light transmission caused by movement of the light shielding portion 610 formed at the rear end of the drive cam ring 600 in the rotational direction. And a plurality of reference positions of the drive cam ring 600 are detected.

  Reference numeral 22 denotes an outer cylinder fixed to the rear lens barrel 11.

  FIGS. 4A and 4B are perspective views showing the relationship between the drive cam ring 600 and the (deceleration) gear unit 300. FIG. The lens barrel is provided with a gear train that transmits the driving force of the DC motor 100 to the driving cam ring 600. The gear ratio (reduction ratio) of the last stage of the gear train in the imaging region from the wide-angle end to the telephoto end of the photographing optical system is smaller than the gear ratio of the last stage of the gear train in the retracted state. This achieves noise reduction in the shooting area.

  Here, in this embodiment, the gear train is engaged with the gear on the cam ring side (driven member side gear) fixed to the outer periphery of the drive cam ring 600 and the gear, and is rotated by the DC motor 100. Motor side gear (drive means side gear). The last stage of the gear train refers to a pair in which the driven member side gear and the driving means side gear are engaged. The gear ratio of the last stage of the gear train is a value obtained by dividing the number of teeth of the driven member side gear by the number of teeth of the driving means side gear in the pair.

  The drive cam ring 600 is a driven member side gear, and has a first gear 600a, a second gear 600b, and a first friction wheel (friction gear) 600c on the side of the protruding portion at the end of the outer lens barrel 11 side of the outer periphery. Have As shown in FIG. 4B, the gear unit 300 has a three-stage configuration having a third gear 300a, a fourth gear 300b, and a second friction wheel 300c as driving means side gears.

  As shown in FIG. 4A, the first gear 600a, the second gear 600b, and the first friction wheel 600c have the same center axis and are formed in different center angle ranges when viewed from the center axis of the drive cam ring 600. Has been. That is, the first gear 600a is formed in the center angle range A, the second gear 600b is formed in the center angle range B, and the first friction wheel 600 is formed in the center angle range C between the center angle ranges A and B. Has been. The central angle ranges A, C, and B do not overlap and are continuous.

  Further, as shown in FIG. 4B, the positions in the optical axis direction of the first gear 600a, the second gear 600b, and the first friction wheel 600c are also different. The first gear 600a is formed on the image side, and the second gear 600b is formed on the object side. The effective portion of the first friction wheel 600c (the portion in contact with the friction wheel 300c) is a portion that protrudes downward (to the first gear 600a side) from the second gear 600b. The first gear 600a protrudes in the optical axis direction from the effective portion that actually engages with the third gear 300a.

  When viewed in the radial direction of the drive cam ring 600, as shown in FIG. 4A, the outer diameter of the second gear 600b is larger than the outer diameter of the first gear 600a. Further, the outer diameter of the first friction wheel 600c is larger than the outer diameter of the first gear 600a, and the outer diameter of the second gear 600b is larger than the outer diameter of the first friction wheel 600c.

  As shown in FIG. 4B, a notch is formed in a portion corresponding to a central angle range B obtained by extending the first gear 600a in the circumferential direction. No gear is formed in the notch, and the diameter of the notch is smaller than the outermost diameter of the first gear 600a. In the center angle range C, a notch is formed in a part of the portion where the effective portion of the first gear 600a is extended in the circumferential direction, and the other portion is the first friction wheel 600c. A friction wheel is formed at a position corresponding to the second gear 600b in the central angle ranges A and C. The outer diameter of this friction wheel is the same as that of the friction wheel 600c. The first gear 600a is formed at a location where the first friction wheel 600c is extended in the circumferential direction in the central angle range A, and the above-described notch is formed at a location corresponding to the first friction wheel 600c in the central angle range B. Yes.

  The fourth gear 300b has a pitch circle diameter different from that of the third gear 300a, and the second friction wheel 300c has a freely configured phase. A second friction wheel 300c is disposed between the third gear 300a and the fourth gear 300b so as to be integrated, and the third gear 300a, the fourth gear 300b, and the second friction wheel 300c are coaxially coupled. . The axis 301 extends parallel to the optical axis Oa. In the gear unit 300, the outer diameter increases in the order of the fourth gear 300b, the second friction wheel 300c, and the third gear 300a.

  The third gear 300a can be engaged with the first gear 600a of the drive cam ring 600 in the non-photographing region from the retracted state to the wide angle end. Since the third gear 300a has a larger outer diameter than the fourth gear 300b and the second friction wheel 300c, the fourth gear 300b and the friction wheel 300c are in a state where the third gear 300a is engaged with the first gear 600a. Is away from the drive cam ring 600.

  The fourth gear 300b can be engaged with the second gear 600b of the drive cam ring 600 in the imaging region from the wide-angle end to the telephoto end of the imaging optical system. The gear ratio (for example, 5/1) of the last stage of the gear train obtained by dividing the number of teeth of the second gear 600b by the number of teeth of the fourth gear 300b is the number of teeth of the first gear 600a by the number of teeth of the third gear 300a. It is smaller than the gear ratio (for example, 20/1) of the final stage of the divided gear train.

  When the first gear 600a and the third gear 300a are engaged, the second gear 600b and the fourth gear 300b are not engaged, and when the second gear 600b and the fourth gear 300b are engaged, the first gear 600a. And the third gear 300a are not engaged.

  In a state in which the fourth gear 300b is engaged with the second gear 600b, the third gear 300a and the second friction wheel 300c are located in the notch in the central angle range B of the drive cam ring 600, so Away from. In addition, when the notch is provided in at least one of the first gear 600a and the third gear 300a, when the second gear 600b and the fourth gear 300b are engaged, the first gear 600a and the third gear. It is sufficient if the other side of 300a is arranged in the notch. The fourth gear 300 b is engaged with the gear 200 on the DC motor side, and the gear 200 is engaged with the gear 210. The axes (shafts) of the gears 200 and 210 are also parallel to the optical axis direction. The gear 210 is engaged with a gear train 140 that connects the DC motor 100 to the gear 210.

  The second friction wheel 300c can come into contact with the first friction wheel 600c of the drive cam ring 600. In a state in which the friction wheel 300c is engaged with the friction wheel 600c, the third gear 300a is located at a notch in the center angle range C of the drive cam ring 600, and the friction wheel 300b has a small diameter. There is a state of being away from the friction wheel B. The contact surface (cylindrical surface) between the second friction wheel 300c and the first 600c may be flat, and the driving force is transmitted by frictional force due to surface contact rather than meshing of the gears.

  The DC motor 100 operates in accordance with the drive voltage transmitted from the control circuit 800 via the invisible flexible printed circuit board. The control circuit 800 may be provided in a camera body (not shown) or may be provided in a lens barrel. When the DC motor 100 rotates, the drive cam ring 600 is rotated by the gear unit 300. Reference numeral 110 denotes a photo interrupter as a movement amount detecting means, which has a light emitting element and a light receiving element. The photo interrupter 110 outputs to the control circuit (control means) 800 an output signal indicating the light transmitting state and the light blocking state by the rotation of the light blocking blade 120 fixed to the motor shaft 130 of the DC motor 100.

  Note that the number of photo interrupters 110 is not limited, and more accurate rotation detection may be performed by arranging another photo interrupter at a position of 90 degrees with respect to the motor shaft 130.

  FIG. 5 is a development view of the first group cam groove 601 and a diagram for explaining a gear engagement state.

  As shown in the figure, when the lens barrel is displaced from the retracted position to the telephoto position, the third gears 300a and 600a mesh in the non-photographing area 703 and the non-photographing area 701 before the photographing area from the retracted position, and the fourth gear 300b. The second friction wheel 300c is separated from the drive cam ring 600.

  Thereafter, the flat cylindrical surfaces of the first friction wheel 600c and the second friction wheel 300c come into contact with each other in at least a part of the non-photographing region 702 from the front of the photographing region to the wide-angle end that is the end of the photographing region. Thereby, the second friction wheel 300c transmits the driving force of the DC motor 100 to the first friction wheel 600c. The third gear 300a and the fourth gear 300b are separated from the drive cam ring 600 and function as a clutch area adjacent to the imaging area. The gear ratio of the last stage of the gear train in the imaging area is smaller than the gear ratio of the last stage of the gear train in the area excluding the clutch area in the non-imaging area.

  If a high load force is transmitted between the first friction wheel 600c and the second friction wheel 300c, there is a risk of slipping. Therefore, it is preferable to flatten the surface so as to extend in the circumferential direction and reduce the load torque as in this embodiment. In addition, since a slight slip may occur even at a low load, a cam origin detection sensor (origin detection means) for detecting the origin (rotation position) of the drive cam ring 600 is provided at this position and an error caused by the slip Is preferably corrected. The origin detection means may be provided immediately before or after the gear ratio is switched.

  Thereafter, in the imaging region 704 from the wide-angle end to the telephoto end, the fourth gears 300b and 600b are engaged, and the third gear 300a and the friction wheel 300c are separated from the drive cam ring 600.

  FIG. 6 is a block diagram relating to the expansion / contraction control of the lens barrel of the present embodiment. 7 to 9 are plan views showing the engagement state of the gear with respect to the lens barrel position.

  The control circuit 800 detects the rotational speed of the drive cam ring 600 from the output signal of the photo interrupter 110. The control circuit 800 adjusts the drive voltage to the DC motor 100 via the speed control circuit 810 that is a part of the control circuit 800 based on the detection result of the rotation speed, and the DC voltage is adjusted so as to obtain an arbitrary rotation speed. The motor 100 is feedback-controlled. In addition, the control circuit 800 acquires the amount of movement of the drive cam ring 600 from the output signal of the photo interrupter 110, and grasps the current position of the drive cam ring 600 together with the output of the cam origin detection sensor 802. Then, the DC motor 100 is feedback-controlled through the position control circuit 820 which is a part of the control circuit 800 so that the current position of the drive cam ring 600 becomes an arbitrary position.

  When the lens barrel is in the retracted state shown in FIG. 1 and an instruction to turn on the power is received from the user, the control circuit 800 causes a current to flow from the control circuit 800 to the DC motor 100 to extend the lens barrel. FIG. 7 shows an engaged state of the gear at this time, and the third gears 300a and 600a having a high gear ratio are engaged with each other. This state corresponds to the non-photographing areas 703 and 701 in FIG.

  Thereafter, when a current is further supplied from the control circuit 800 to the DC motor 100, the lens barrel enters the front of the imaging region. FIG. 8 shows an engaged state of the gear at this time, and the friction wheel units 300c and 600c are engaged with each other. This state corresponds to a non-photographing area 702 that is a clutch area in FIG.

  Thereafter, when a current is further supplied from the control circuit 800 to the DC motor 100, the lens barrel reaches the cam origin position where the cam origin detection sensor 802 is provided in front of the wide angle end. When the control circuit 800 receives a signal that detects the cam origin from the cam origin detection sensor 802, the control circuit 800 may recognize that the position of the lens barrel or the drive cam ring 600 of the imaging device using the lens barrel is at the origin. Yes, set the origin position. As a result, it is possible to reset the error between the number of pulses generated from the photo interrupter due to slipping of the friction wheels 300c and 600c and the actual cam drive amount.

  Thereafter, when a current is further supplied from the control circuit 800 to the DC motor 100, the lens barrel enters the imaging region and becomes the wide-angle end shown in FIG. FIG. 9 shows the gear engagement state at this time, and the fourth gears 300b and 600b having a gear ratio lower than that of the third gears 300a and 600a are engaged with each other. When entering the imaging area, the user reciprocates between the wide-angle end and the telephoto end according to an instruction from the user or the imaging apparatus.

  When the lens barrel is instructed to be retracted into the retracted state in response to an instruction from the user or the imaging device within the imaging region, the lens barrel passes through the wide-angle end while the fourth gears 300b and 600b are engaged and reaches the non-imaging region. . Next, the origin is detected by the cam origin detection sensor 802, and the pulse of the photo interrupter 110 is reset again. When the drive cam ring 600 is further rotated in the retracted direction after the reset, the third gears 300a and 600a are engaged through the contact between the friction wheels 300c and 600c, and the rotation continues in the retracted direction. Unlike driving from the retracted to the wide-angle end, when driving from the wide-angle end to the retracted side, the slip error in the friction wheel cannot be eliminated because it passes through the friction wheel after reset. However, a flat region 703 extending in the circumferential direction is provided in the first group cam groove 601 capable of absorbing the error in the collapsed region, and by inserting a little more than the required number of pulses of the photo interrupter 110, the collapse is insufficient due to the error, or to the mechanical end. Collisions can be avoided. The lens barrel housed in this way advances from the retracted state to the position immediately before the shooting area by the power ON signal from the user or the imaging device, switches the gear, detects the origin after switching the gear, and is ready to shoot again It becomes.

  FIG. 10 shows the amount of torque required to move the drive cam ring 600. The horizontal axis indicates the position of the lens barrel, and the vertical axis indicates the torque of the DC motor 100. Referring to FIG. 10, it can be seen that the position where the torque is most required to move the drive cam ring 600 is when the drive cam ring 600 is moved from the retracted position to the front of the photographing region.

  FIGS. 11A and 11B are graphs showing the rotational speed of the DC motor 100 and the noise level at that time when the lens barrel is driven from the retracted state to the telephoto end at a constant speed. In FIG. 11A, the horizontal axis indicates the position of the lens barrel, and the vertical axis indicates the rotational speed (rpm) of the DC motor 100. In FIG. 11B, the horizontal axis indicates the position of the lens barrel, and the vertical axis indicates the noise level (dB). In FIG. 11A and FIG. 11B, the solid line represents the present embodiment in which the gear ratio of the final stage of the gear train is changed between the non-photographing area and the photographing area, and the broken line represents the gear ratio of the final stage of the gear train. This shows a conventional example in which the non-photographing area and the photographing area are constant.

  According to FIGS. 11 (a) and 11 (b), the revolving speed of the DC motor 100 increases as a result of being driven at a high gear ratio from the retracted position where the most torque is required to the end of the wide angle. It can be seen that the noise is increasing. Thereafter, between the wide-angle end and the telephoto end where the required torque becomes small, the lens barrel moves with a small gear ratio in this embodiment, and moves with a large gear ratio in the conventional example. As a result, in the present embodiment, it can be seen that the rotational speed of the DC motor 100 is low, and the noise in the imaging region is smaller than in the conventional example.

  As described above, in the present embodiment, when the driving force from the DC motor 100 is transmitted to the drive cam ring 600 via the gear train, the gear ratio in the imaging region is changed to be smaller than that in the non-imaging region. Therefore, it is possible to reduce the noise in the imaging region.

  In the present embodiment, the gear ratio in the photographing region is smaller than the gear ratio in the non-photographing region from the retracted state to the wide-angle end using the notch of the drive cam ring 600 and the size of the gear of the cam unit 300. In this way, the gear ratio is automatically switched. However, gear switching means may be provided that detects the photographing region and the non-photographing region and automatically switches the gear ratio of the gear train according to the detection result.

  As mentioned above, although the Example of this invention was described, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary. The imaging device having the lens barrel described above also constitutes one aspect of the present invention.

  The lens apparatus can be applied to the field of digital still cameras and digital video cameras.

DESCRIPTION OF SYMBOLS 100 ... DC motor (drive means), 600 ... Drive cam ring (driven member), 600a ... 1st gear (gear train), 600b ... 2nd gear (gear train), 600c ... 1st friction wheel (gear train) , 300a ... third gear (gear train), 300b ... fourth gear (gear train), 300c ... second friction wheel (gear train)

Claims (16)

A retractable lens device that houses a photographing optical system for forming an optical image of a subject and has a zooming function,
Driving means;
A driven member that is rotationally driven by the driving means, thereby realizing a displacement between the retracted state and the extended state, and realizing the scaling function;
A gear train for transmitting the driving force of the driving means to the driven member;
Have
The lens apparatus according to claim 1, wherein a gear ratio of a last stage of the gear train in a photographing region from a wide angle end to a telephoto end of the photographing optical system is smaller than a gear ratio of the gear train in the retracted state. The gear train is
A driven member side gear fixed to the outer periphery of the driven member;
A driving means side gear engaged with the driven member side gear and driven to rotate by the driving means;
Have
2. The lens device according to claim 1, wherein the gear ratio of the final stage of the gear train is a value obtained by dividing the number of teeth of the driven member side gear by the number of teeth of the driving means side gear. . The driven member side gear includes a first gear and a second gear,
The driving means side gear includes a third gear that can be engaged with the first gear of the driven member side gear in a non-photographing region from the retracted state to the wide-angle end of the photographing optical system, and in the photographing region A fourth gear engageable with the second gear of the driven member side gear,
The gear ratio obtained by dividing the number of teeth of the second gear by the number of teeth of the fourth gear is smaller than the gear ratio obtained by dividing the number of teeth of the first gear by the number of teeth of the third gear. Item 3. The lens device according to Item 2.   When the first gear and the third gear are engaged, the second gear and the fourth gear are not engaged, and when the second gear and the fourth gear are engaged, the first gear is engaged. The lens device according to claim 3, wherein the third gear is not engaged.   The first gear is provided with a notch, and the third gear is disposed in the notch of the first gear when the second gear and the fourth gear are engaged. The lens device according to claim 4.   The fourth gear is coaxial with the third gear, has an outer diameter smaller than that of the third gear, and when the first gear and the third gear are engaged, the second gear and the fourth gear. The lens device according to claim 4, wherein the lens devices are separated from each other.   The center diameter of the first gear and the center axis of the second gear coincide with each other, and the outer diameter of the second gear is larger than the outer diameter of the first gear. The lens apparatus of any one of them. The non-photographing area has a clutch area adjacent to the photographing area,
7. The lens device according to claim 4, wherein the third gear and the fourth gear are not engaged with each other in at least a part of the clutch region in the non-photographing region. The driven member side gear further includes a first friction wheel,
The driving means side gear further includes a second friction wheel that contacts the first friction wheel of the driven member side gear in the clutch region and transmits the driving force to the first friction wheel. The lens device according to claim 8.   The center axis of the first friction wheel coincides with the center axis of the first gear and the center axis of the second gear, and the outer diameter of the first friction wheel is larger than the outer diameter of the first gear, The lens apparatus according to claim 9, wherein an outer diameter of the second gear is larger than an outer diameter of the first friction wheel.   The second friction wheel is disposed between the third gear and the fourth gear, is coaxial with the third gear and the fourth gear, has a smaller diameter than the third gear, and is smaller than the fourth gear. The lens device according to claim 9, wherein the lens device has a large diameter.   The lens apparatus according to claim 8, wherein a gear ratio of the shooting area is smaller than a gear ratio of the non-shooting area excluding the clutch area.   The lens apparatus according to claim 1, further comprising a detection unit that detects a rotational position of the driven member immediately before or after the gear ratio is switched.   The lens apparatus according to claim 8, further comprising a detecting unit that detects a rotational position of the driven member in the clutch region.   15. The driven member includes a cam groove that guides displacement between the retracted state and the extended state, and the cam groove has a region extending in a circumferential direction in the retracted state. The lens apparatus of any one of these.   An imaging device comprising the lens device according to claim 1.