Lens device and imaging system

Abstract

To provide a lens device that can reduce the overall length without an increase in size.SOLUTION: A lens device (101) includes a first group (111), a second group (112), a cam barrel (108), and a guide barrel (107). The cam barrel has a first cam groove (108a) and a second cam groove (108b) for moving the first group and the second group, respectively, in an optical axis direction. The guide barrel has a first guide groove (107a) and a second guide groove (107b) for restricting rotation of the first group and the second group, respectively, around an optical axis. The second group has a base group (112c) and a holder group (112b). The holder group is located closer to the first group than the base group in the optical axis direction. As the lens device transitions from an imaging state to a non-imaging state, due to an action of the cam barrel and the guide barrel, the first group moves closer to the second group, and the second group moves closer to the first group, so that the holder group and the first group contact with each other.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a lens device and an imaging system.

Background Art

[0002] Patent Document 1 discloses a lens barrel having a retracting mechanism that shortens the overall length in the optical axis direction by widening the distance between a first group and a second group in a state where shooting is possible, but narrowing the distance between the first group and the second group in a retracted state where shooting is restricted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the lens barrel disclosed in Patent Document 1, in order to retract from the shooting end (wide-angle end or telephoto end), a sufficient distance between the first group and the second group is required. Therefore, the overall length of the lens at the wide-angle end or telephoto end becomes long, and the lens diameter and the barrel diameter also become large. Further, if a sufficient distance between the first group and the second group is not ensured, there is a possibility that the first group and the second group may collide, so that retraction cannot be performed from the wide-angle end or telephoto end.

[0005] Therefore, an object of the present invention is to provide a lens device capable of shortening the overall length without increasing the size.

Means for Solving the Problems

[0006] The lens device as one aspect of the present invention is a lens device having a first group, a second group, a cam cylinder, and a guide cylinder. The cam cylinder has a first cam groove for moving the first group in the optical axis direction and a second cam groove for moving the second group in the optical axis direction. The guide cylinder has a first guide groove for restricting the rotation of the first group around the optical axis and a second guide groove for restricting the rotation of the second group around the optical axis. The second group has a base group and a holder group. The holder group is located closer to the first group than the base group in the optical axis direction. When the lens device shifts from the shooting state to the non-shooting state, due to the action of the cam cylinder and the guide cylinder, the first group moves closer to the second group, and the second group moves closer to the first group, so that the holder group and the first group come into contact with each other.

[0007] Other objects and features of the present invention will be described in the following embodiments.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a lens device capable of shortening the overall length without increasing the size.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7(a)

Figure 7(b)

Figure 7(c)

Figure 7(d)

Figure 8

Figure 9

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same reference numerals throughout the drawings indicate the same or corresponding parts. In this embodiment, an interchangeable lens, which is an example of an optical device, will be described. However, the present invention can be variously modified and changed within the scope of the gist thereof, such as in a lens-integrated camera.

[0011] First, with reference to FIGS. 1(a) and 1(b), the imaging system 100 in this embodiment will be described. FIGS. 1(a) and 1(b) are external perspective views of the imaging system 100. FIG. 1(a) is a perspective view seen from the front side (subject side), and FIG. 1(b) is a perspective view seen from the back side (image plane side). In this embodiment, as shown in FIG. 1(a), the optical axis direction of the imaging optical system accommodated in the interchangeable lens 101, which is the direction in which the optical axis OA extends (the direction along the optical axis), is defined as the X-axis direction, and the directions orthogonal to the optical axis direction are defined as the Z-axis direction (horizontal direction) and the Y-axis direction (vertical direction). Hereinafter, the Z-axis direction and the Y-axis direction are also collectively referred to as the Z / Y-axis direction. Further, the rotation direction around the Z-axis is defined as the pitch direction, and the rotation direction around the Y-axis is defined as the yaw direction. The pitch direction and the yaw direction (hereinafter, also collectively referred to as the pitch / yaw direction) are rotation directions around two axes, the Z-axis and the Y-axis, which are orthogonal to each other.

[0012] The imaging system 100 includes a camera body (digital camera, imaging device) 1 and an interchangeable lens (lens device, lens barrel) 101 that can be attached to and detached from the camera body 1. However, this embodiment is not limited thereto, and is also applicable to an imaging device in which the camera body and the lens device are integrally configured.

[0013] On the left side (right side when viewed from the back) of the camera body 1 when viewed from the front, a grip portion 2 for the user to hold the camera body 1 by hand is provided. Also, a power operation unit 3 is arranged on the upper surface of the camera body 1. When the user turns on the power operation unit 3 when the camera body 1 is in the power-off state, power supply starts and the camera body 1 enters the power-on state, and a computer program such as the origin detection process of the focus group is executed, and the camera enters the shooting standby state. Then, when the user turns off the power operation unit 3 when the camera body 1 is in the power-on state, the camera body 1 enters the power-off state.

[0014] Also, a mode dial 4, a release button 5, and an accessory shoe 6 are provided on the upper surface of the camera body 1. By rotating the mode dial 4 by the user, the shooting mode can be switched. The shooting modes include a manual still image shooting mode in which the user can arbitrarily set shooting conditions such as the shutter speed and aperture value, an auto still image shooting mode in which an appropriate exposure amount can be obtained automatically, and a video shooting mode for shooting video. Also, by pressing the release button 5 halfway by the user, shooting preparation operations such as autofocus and automatic exposure control can be instructed, and by pressing it fully, shooting can be instructed. An accessory (camera accessory) of an illumination or light-emitting device such as an external flash is detachably attached to the accessory shoe 6.

[0015] The interchangeable lens 101 includes a lens mount 102 that can be mechanically and electrically connected to a camera mount 7 provided on the camera body 1. The lens mount 102 and the camera mount 7, each having an annular shape, are formed of a conductive metal material and are detachable via a bayonet connection (not shown). As long as the camera system adopts a common mount shape, the combination of the interchangeable lens 101 and the camera body 1 is not restricted.

[0016] An imaging optical system that forms a subject image by imaging light from the subject is accommodated in the interchangeable lens 101. On the outer periphery of the interchangeable lens 101, a zoom operation ring (operation member) 103 that can be rotated about the optical axis (around the optical axis) by a user operation is provided. When the zoom operation ring 103 is rotated by the user, the zoom group constituting the imaging optical system moves to a predetermined use position corresponding to the angle of the zoom operation ring 103 within the range from the wide-angle end to the telephoto end. In this way, the user can perform shooting at a desired angle of view. Further, although details will be described later, in the present invention, a retracted end where shooting is further restricted is provided at the position where the interchangeable lens 101 is most retracted, after rotating the zoom operation ring 103 from the telephoto end to the wide-angle end.

[0017] As shown in FIG. 1(b), a rear operation unit 8 and a display unit 9 are provided on the rear surface of the camera body 1. The rear operation unit 8 includes a plurality of buttons and dials to which various functions are assigned. When the power of the camera body 1 is on and the still image or video shooting mode is set, a through image of the subject image captured by the imaging device described later is displayed on the display unit 9. Further, shooting parameters indicating shooting conditions such as shutter speed and aperture value are displayed on the display unit 9, and the user can change the set value of the shooting parameters by operating the rear operation unit 8 while viewing the display. The rear operation unit 8 includes a playback button for instructing playback of the recorded captured image, and when the user operates the playback button, the captured image is reproduced and displayed on the display unit 9. Note that the display unit 9 may be a touch panel type and have the same function as the rear operation unit 8.

[0018] Next, with reference to FIG. 2, the electrical and optical configurations of the imaging system 100 will be described. FIG. 2 is a block diagram of the imaging system 100. The camera body 1 includes a power supply unit 10 that supplies power to the camera body 1 and the interchangeable lens 101, a power operation unit 3, a mode dial 4, a release button 5, and an operation unit 11 that includes a touch panel function of the rear operation unit 8 and the display unit 9. The overall system control of the camera body 1 and the interchangeable lens 101 in this embodiment is performed by the camera control unit 12 provided in the camera body 1 and the lens control unit 104 provided in the interchangeable lens 101 cooperating with each other. Note that a computer for controlling the camera body 1 and the interchangeable lens 101 is built into each of the camera control unit 12 and the lens control unit 104, and the overall system of the camera body 1 and the interchangeable lens 101 is controlled by operating them in cooperation.

[0019] The camera control unit 12 reads and executes a computer program stored in the storage unit 13. At that time, the camera control unit 12 communicates with the lens control unit 104 via the communication terminal of the electrical contact 105 provided on the lens mount 102 for various control signals, data, and the like. The electrical contact 105 includes a power supply terminal that supplies power from the power supply unit 10 described above to the interchangeable lens 101.

[0020] The imaging optical system of the interchangeable lens 101 is connected to the zoom operation ring 103 and has a zoom group 110 that moves in the optical axis direction to change the angle of view, and a diaphragm group (aperture diaphragm unit) 301 that performs a light amount adjustment operation. Further, the imaging optical system has a lens anti-shake group 113 including a shift lens as an anti-vibration element, and reduces image blur by moving (shifting) in the Z / Y axis direction orthogonal to the optical axis. Furthermore, the imaging optical system has a focus group 116 including a focus lens that moves in the optical axis direction to perform focus adjustment (focusing). The interchangeable lens 101 has a diaphragm drive unit 302 that drives the diaphragm group 301, an anti-vibration drive unit 311 that moves the lens anti-shake group 113, and a focus drive unit 601 that moves the focus group 116.

[0021] The camera body 1 includes a shutter unit 14, a shutter drive unit 15, an imaging device 16, an image processing unit 17, and a camera control unit 12. The shutter unit 14 controls the amount of light that is imaged by the imaging optical system within the interchangeable lens 101 and exposed by the imaging device 16. The imaging device 16 photoelectrically converts the subject image formed by the imaging optical system and outputs an imaging signal. The image processing unit 17 performs various image processes on the imaging signal and then generates an image signal. The display unit 9 displays the image signal (through image) output from the image processing unit 17, displays the shooting parameters, or reproduces and displays the captured images recorded in the storage unit 13 or a recording medium (not shown).

[0022] The camera control unit 12 controls the focus drive unit 601 in response to a shooting preparation operation (such as a half-press operation of the release button 5) at the operation unit 11. For example, when an autofocus operation is instructed, the focus detection unit 18 determines the focus state of the subject image formed on the imaging device 16 based on the image signal generated by the image processing unit 17, generates a focus signal, and transmits it to the camera control unit 12. At the same time, the focus drive unit 601 transmits information regarding the current position of the focus group 116 to the camera control unit 12. The camera control unit 12 compares the focus state of the subject image with the current position of the focus group 116, calculates the focus drive amount from the deviation amount, and transmits it to the lens control unit 104. Then, the lens control unit 104 moves the focus group 116 to the target position in the optical axis direction via the focus drive unit 601 to correct the focus shift of the subject image.

[0023] The focus drive unit 601 includes a focus motor that functions as an actuator and a photointerrupter that detects the origin position of the focus group 116. Generally, a stepping motor, which is a type of actuator, is often adopted as the focus motor. Note that as the focus motor, a DC motor equipped with an encoder, an ultrasonic motor, a servo motor, or the like may also be adopted. Further, the photointerrupter directly receives the light emitted from the light emitting unit at the light receiving unit. Instead of this, a photoreflector that receives the reflected light from the reflecting surface or a brush that contacts the conductive pattern and electrically detects a signal may be used as the detection unit.

[0024] The camera control unit 12 controls the driving of the diaphragm group 301 and the shutter unit 14 via the diaphragm drive unit 302 and the shutter drive unit 15 according to the set value of the diaphragm value or the shutter speed received from the operation unit 11. For example, when the operation of automatic exposure control is instructed, the camera control unit 12 receives the luminance signal generated by the image processing unit 17 and performs photometry calculation. Based on the result of this photometry calculation, the camera control unit 12 controls the diaphragm drive unit 302 according to the shooting instruction operation (such as the full press operation of the release button 5) at the operation unit 11. At the same time, the camera control unit 12 controls the driving of the shutter unit 14 via the shutter drive unit 15 and performs the exposure process by the imaging element 16.

[0025] The camera body 1 has a pitch shake detection unit 19 and a yaw shake detection unit 20 as shake detection means capable of detecting image shake due to the user's hand shake or the like. The pitch shake detection unit 19 and the yaw shake detection unit 20 respectively detect image shake in the pitch direction (the rotation direction around the Z axis) and the yaw direction (the rotation direction around the Y axis) using an angular velocity sensor (vibration gyro) or an angular acceleration sensor and output a shake signal.

[0026] The camera control unit 12 calculates the shift position in the Y-axis direction of the lens anti-shake group 113 using the shake signal from the pitch shake detection unit 19. Similarly, the camera control unit 12 calculates the shift position in the Z-axis direction of the lens anti-shake group 113 using the shake signal from the yaw shake detection unit 20. Then, the camera control unit 12 moves the lens anti-shake group 113 to the target position in the Z / Y-axis direction via the anti-shake drive unit 311 according to the calculated shift positions in the pitch / yaw directions, and reduces image blur during exposure and during through-image display.

[0027] The interchangeable lens 101 has a zoom operation ring 103 for changing the angle of view of the imaging optical system, and a zoom detection unit 106 for detecting the angle of the zoom operation ring 103. The zoom detection unit 106 detects the angle of the zoom operation ring 103 operated by the user as an absolute value, and is configured using, for example, a resistive linear potentiometer. Information regarding the angle of view detected by the zoom detection unit 106 is transmitted to the lens control unit 104 and reflected in various controls by the aforementioned camera control unit 12. On the other hand, a part of the aforementioned various information is recorded in the storage unit 13 or a recording medium (not shown) together with the captured image.

[0028] Next, with reference to FIGS. 3 to 5, the positional relationship of the main components in the interchangeable lens 101 will be described. FIGS. 3 to 5 are cross-sectional views on the XY plane including the optical axis OA, and the center line shown here substantially coincides with the optical axis OA determined by the imaging optical system, and thus will be synonymous with the optical axis OA hereinafter.

[0029] FIG. 3 shows the wide-angle end on the short focal length side in zooming, and FIG. 4 shows the telephoto end on the long focal length side in zooming. Both FIGS. 3 and 4 show a state where the imaging optical system of the interchangeable lens 101 is in a photographable position (a state where photography is possible). On the other hand, FIG. 5 shows that the imaging optical system of the interchangeable lens 101 is in a retracted state (a state in the retracted position) when not in use. Also, FIG. 5 shows the retracted end with the shortest overall length in the optical axis direction.

[0030] The telescopic end shown in FIG. 5 is provided further ahead of the wide-angle end in FIG. 3. By rotating the zoom operation ring 103 in one direction, the telescopic end in FIG. 5 transitions to the wide-angle end in FIG. 3, and then from the wide-angle end shown in FIG. 3 to the telephoto end shown in FIG. 4 in sequence. In the present embodiment, the state in which shooting is possible by the imaging optical system is defined as the shooting state, and the state in which the imaging optical system is in the telescopic position is defined as the telescopic state. Note that the state in which shooting is possible means a state in which the functions of the imaging system 100 including the camera body 1 and the interchangeable lens 101 can always operate normally. That the shooting is restricted means that at least a part of the functions of the imaging system 100 including the camera body 1 and the interchangeable lens 101 do not operate normally. For example, in the state where the imaging optical system is in the telescopic position, the shooting act itself (for example, pressing the shutter to shoot a subject) is possible, but due to events such as the focus of the captured image not being in focus, the whole or part of the image may become blurred.

[0031] As shown in FIGS. 3 and 4, in the present embodiment, an optical system with a seven-group configuration is adopted as an example of the imaging optical system. The zoom group 110 moves to different predetermined use positions at the wide-angle end and the telephoto end respectively, and forms an image of the light from the subject on the imaging element 16. The zoom group 110 is composed of a first zoom group 111, a second zoom group 112, a diaphragm group 301, an optical image stabilization group (third zoom group) 113, a fourth zoom group 114, a fifth zoom group 115, a focus group (sixth zoom group) 116, and a seventh zoom group 117. In the present embodiment, the configuration of the imaging optical system is not limited. For example, at least one of the optical image stabilization group 113 and the focus group 116 may function as another zoom group. Also, some lens groups may not be movable and may be fixed.

[0032] In the present embodiment, the first zoom group 111 is described as the first group and the second zoom group is described as the second group. However, the present embodiment is not limited to this, and any two zoom groups (or lens groups) can be applied as the first group or the second group.

[0033] The straight-ahead guide tube 107 is a fixed component (guide tube) fixed to the lens mount 102 via the fixed tube 109. The fixed tube 109 rotatably holds the zoom operation ring 103 around the optical axis. Bayonet claws (not shown) are arranged at equal intervals on the outer peripheral surface of the straight-ahead guide tube 107. On the other hand, a circumferential groove (not shown) is provided on the inner peripheral surface of the cam tube 108. Also, the cam tube 108 is connected to the zoom operation ring 103. When the user rotates the zoom operation ring 103, the cam tube 108 is restricted from moving in the optical axis direction and rotates around the optical axis OA due to the engagement between the bayonet claws and the circumferential groove.

[0034] Also, although details will be described later, a straight-ahead guide groove that restricts the movement of the zoom group 110 in the rotation direction and guides straight-ahead movement in the optical axis direction is formed at equal intervals on the straight-ahead guide tube 107. Also, cam grooves having trajectories at different angles in the rotation direction are formed at equal intervals on the cam tube 108 corresponding to the zoom group 110. On the other hand, a plurality of rollers are provided on the zoom group 110, and each roller is engaged with the corresponding straight-ahead guide groove and cam groove. When the user rotates the zoom operation ring 103, the cam tube 108 rotates, and the rollers move (advance and retreat) the zoom group 110 in the optical axis direction while restricting the movement in the rotation direction due to the engagement between the straight-ahead guide groove and the cam groove.

[0035] The interchangeable lens 101 of this embodiment has a lens retracting mechanism, details of which will be described later. With the lens retracting mechanism, it becomes possible to further retract the zoom group 110 to the back side (image plane side) during non-photographing. Thereby, the overall length of the interchangeable lens 101 can be shortened, and the portability of the interchangeable lens 101 and the camera body 1 can be enhanced.

[0036] At the wide-angle end shown in FIG. 3, the distance between the second zoom group 112 and the lens anti-shake group (third zoom group) 113 is wide. At the telephoto end shown in FIG. 4, the distance between the first zoom group 111 and the second zoom group 112 is wide. The retracting mechanism narrows these distances respectively, moves them to the storage positions close to each other, and shortens the overall length in the optical axis direction. As shown in FIG. 5, at the retracted end during non-photographing, the zoom groups 110 have moved to the storage positions close to each other. From this state, for example, when the user rotates the zoom operation ring 103 to the wide-angle end, the zoom groups 110 are extended to the front side (subject side) and move to the predetermined use positions, reaching the photographable state shown in FIG. 3.

[0037] Next, with reference to FIG. 6, the configuration of the second zoom group 112 will be described in detail. FIG. 6 is an exploded perspective view of the second zoom group 112. The holder group 112b holds the lens (lens group) 112a inside thereof and holds the cover 112d on the side of the first zoom group 111. In the present embodiment, the cover 112d is a molded part, but depending on the optical design, etc., it may be a sheet part, for example.

[0038] The base group 112c holds a plurality of rollers (followers) 112e at equal intervals on its outer periphery and holds a plurality of guide shafts 112h on the side of the holder group 112b. The guide shaft 112h has a cylindrical shape and is press-fitted and held in the base group 112c. The holder group 112b is located closer to the first zoom group 111 than the base group 112c in the optical axis direction. A plurality of biasing members (first biasing members) 112f are provided between the holder group 112b and the base group 112c. In the present embodiment, the biasing member 112f is a compression coil spring, but as long as the holder group 112b and the base group 112c can be biased in a direction away from each other, the type of spring is not limited, and an elastic member other than a spring may also be used. A plurality of guide holes (not shown) are formed in the holder group 112b. The holder group 112b is positioned and held on the base group 112c by fitting with the guide shafts 112h in the plurality of guide holes.

[0039] Further, the second zoom group 112 has a screw 112g coaxially with the guide shaft 112h. The screw 112g is fixed to the base group 112c via the guide shaft 112h from the cover 112d side of the holder group 112b. Thereby, the holder group 112b is positioned with respect to the base group 112c by the guide shaft 112h and held so as to be separated from each other by the biasing member 112f, thus forming the second zoom group 112.

[0040] Next, with reference to FIGS. 7(a) to (d) and FIGS. 8(a) to (d), the relationship between the first zoom group 111 and the second zoom group 112 when the interchangeable lens (lens barrel) 101 transitions from the shooting state to the non-shooting state and the retracted state will be described. FIGS. 7(a) to (d) are cross-sectional views of the interchangeable lens 101 showing only the first zoom group 111 and the second zoom group 112. FIG. 7(a) shows a cross-section at one end in the shooting state. FIG. 7(b) shows a cross-section when transitioning from the shooting state to the non-shooting state. FIG. 7(c) shows a cross-section when transitioning from the non-shooting state to the retracted end. FIG. 7(d) shows a cross-section at the retracted end. FIGS. 8(a) to (d) are explanatory views of the cam barrel 108 and the click mechanism 700. FIG. 8(a) is a developed view of the cam barrel 108 with respect to the second zoom group 112. FIG. 8(b) is an explanatory view of the biasing force by the biasing member 112f. FIG. 8(c) is a schematic cross-sectional view of the click mechanism 700 provided in the interchangeable lens 101. FIG. 8(d) is an explanatory view of the click force by the click mechanism 700.

[0041] The rotation of the first zoom group 111 around the optical axis is restricted by a plurality of straight grooves (first guide grooves) 107a provided in the straight guide cylinder 107, and it is held so as to be movable (retractable) in the optical axis direction by a plurality of cam grooves (first cam grooves) 108a provided in the cam barrel 108. Similarly, the rotation of the second zoom group 112 around the optical axis is restricted by a plurality of straight grooves (second guide grooves) 107b provided in the straight guide cylinder 107, and it is held so as to be movable (retractable) in the optical axis direction by a plurality of cam grooves (second cam grooves) 108b provided in the cam barrel 108.

[0042] As shown in FIG. 7(a), when the interchangeable lens 101 is at one end in the shooting state, the first zoom group 111 and the second zoom group 112 are in a state where the distance between them is the closest. In this embodiment, one end of the interchangeable lens 101 is the wide-angle end, but depending on the optical design, etc., it may be the telephoto end. When the interchangeable lens 101 is in the shooting state, as described above, the base group 112c and the holder group 112b that constitute the second zoom group 112 are biased in a direction away from each other by the biasing member 112f.

[0043] As shown in FIG. 7(b), when the interchangeable lens 101 transitions from one end in the shooting state to the non-shooting state, due to the action of the straight guide cylinder 107 and the cam cylinder 108, the first zoom group 111 moves toward the second zoom group 112 along the cam groove 108a of the cam cylinder 108 (arrow a). At this time, the base group 112c moves toward the first zoom group 111 along the cam groove 108b due to the action of the straight guide cylinder 107 and the cam cylinder 108 (arrow c), and the holder group 112b abuts against the first zoom group 111.

[0044] As described above, the base group 112c and the holder group 112b are biased in a direction away from each other by the biasing member 112f. For this reason, the holder group 112b abuts against the first zoom group 111 and moves toward the base group 112c side along the cam groove 108a (arrow b). As a result, as shown in FIG. 7(b), the biasing member 112f is compressed, the holder group 112b moves toward the base group 112c side integrally with the first zoom group 111, and the first zoom group 111 and the second zoom group 112 are in a state where they are closest to each other.

[0045] As shown in FIG. 7(c), when the interchangeable lens 101 further moves toward the lens barrel end from the state of FIG. 7(b), the first zoom group 111 further moves toward the second zoom group 112 along the locus of the cam groove 108a by the action of the straight guide cylinder 107 and the cam cylinder 108 (arrow a). When the first zoom group 111 and the second zoom group 112 move further toward the lens barrel end from the state where they are closest to each other (the state of FIG. 7(b)), the base group 112c moves toward the lens barrel end along the cam groove 108b by the action of the straight guide cylinder 107 and the cam cylinder 108 (arrow c). As described above, since the first zoom group 111 and the holder group 112b are in contact with each other, the holder group 112b moves toward the base group 112c along the cam groove 108a (arrow b).

[0046] As shown in FIG. 7(d), when the interchangeable lens 101 completes the transition to the lens barrel retracted state, the first zoom group 111 moves toward the second zoom group 112 along the locus of the cam groove 108a by the action of the straight guide cylinder 107 and the cam cylinder 108 (arrow a) and moves to the lens barrel end. The base group 112c moves to the lens barrel end along the cam groove 108b by the action of the straight guide cylinder 107 and the cam cylinder 108 (arrow c). As described above, since the first zoom group 111 and the holder group 112b are in contact with each other, the holder group 112b moves toward the base group 112c along the cam groove 108a (arrow b). By the above operations, the interchangeable lens 101 transitions from the shooting state to the non-shooting state and completes the transition to the lens barrel retracted state (lens barrel end).

[0047] Here, referring to FIG. 8(a) and paying attention to the gradient a of the cam groove 108a and the gradient b of the cam groove 108b provided in the cam cylinder 108, the relationship is gradient a > gradient b. For this reason, the first zoom group 111 and the second zoom group 112 gradually move apart as they transition to the lens barrel retracted state. Also, as described with reference to FIG. 7(b), when the interchangeable lens 101 transitions from the shooting state to the non-shooting state, the first zoom group 111 and the second zoom group 112 are in the state where they are closest to each other.

[0048] From the above, the biasing force by the biasing member 112f generated between the first zoom group 111 and the second zoom group 112 becomes the highest when shifting from the shooting state to the non-shooting state as shown in FIG. 8(b), and then gradually decreases. That is, the biasing force of the biasing member 112f becomes stronger when moving to the first position so that the holder group 112b approaches the base group 112c integrally with the first zoom group 111 in a state where the holder group 112b is in contact with the first zoom group 111, and becomes weaker as it moves from the first position toward the retracted lens end. This makes it possible to prevent the first zoom group 111 from unexpectedly extending even when an external force is applied when the interchangeable lens 101 is in the retracted state.

[0049] Here, paying attention to the length of the cam cylinder 108 in the optical axis direction, in this embodiment, when shifting from the state of FIG. 7(a) to the state of FIG. 7(b), the holder group 112b moves toward the base group 112c side by the drop a in FIG. 8(a).

[0050] In a conventional lens barrel, to shift from one end in the shooting state to the non-shooting state, the inter-group distance between the first zoom group and the second zoom group is required to be a distance equal to or greater than the drop a in this embodiment. Therefore, the overall length of the cam cylinder and the overall length of the lens barrel become longer, and depending on the optical design, the lens diameter and the lens barrel diameter also become larger by ensuring a sufficient inter-group distance. Also, if a sufficient inter-group distance is not ensured, the first zoom group and the second zoom group collide, so it is impossible to shift from one end in the shooting state to the non-shooting state.

[0051] On the other hand, in this embodiment, when the interchangeable lens 101 shifts from the shooting state to the non-shooting state, the base group 112c moves toward the first zoom group 111 side, and the first zoom group 111 moves toward the second zoom group 112 side. The holder group 112b is in contact with the first zoom group 111 and has a structure that moves toward the base group 112c side integrally with the first zoom group 111. According to this embodiment, therefore, it is possible to shorten the overall length of the cam cylinder, the overall length of the lens barrel, and the overall length of the lens in the retracted state compared to the conventional case, and it is also possible to reduce the lens diameter and the lens barrel diameter.

[0052] Next, with reference to FIGS. 9(a) and 9(b), a click mechanism 700 for giving a click feeling (a sense of moderation) to the operation of the zoom operation ring 103 will be described. FIGS. 9(a) and 9(b) are explanatory views of the click mechanism 700. FIG. 9(a) is a side sectional view of the click mechanism 700, and FIG. 9(b) is a lower sectional view of the click mechanism 700 as seen from the center of the optical axis. FIGS. 9(a) and 9(b) show the arrangement state of the click mechanism 700 in the vicinity of the shooting end in the shooting area described later.

[0053] In FIGS. 9(a) and 9(b), the horizontal axis represents the phase of the zoom operation ring 103 (the rotational position, the position in the direction around the optical axis), schematically showing the relative positional relationship of the components in the zoom, and expressing that the pin member 701 moves relative to the zoom operation ring 103. However, it is the zoom operation ring 103 that actually rotates, and the phase of the pin member 701 (the position in the direction around the optical axis) is fixed by the fixed cylinder 109.

[0054] The click mechanism 700 is a mechanism for locking the rotation of the zoom operation ring 103, and is mainly realized by the fixed cylinder 109, the pin member 701, a part of the zoom operation ring 103 (the tapered portion 103a), the outer ring 703, and the biasing member (the second biasing member) 702. The pin member 701 is an engaging member held by the fixed cylinder 109 so as to be linearly movable in the optical axis direction. The pin member 701 has a tip portion 701b, and the side surface adjacent to the tip portion 701b is a tapered portion 701a having a tapered shape.

[0055] The biasing member (the second biasing member) 702 is held by the sleeve shape of the pin member 701, and biases the pin member 701 in the side (X direction) of the fixed cylinder 109 and the zoom operation ring 103 by receiving the reaction force from the outer ring 703. The biasing member 702 is, for example, a compression coil spring, and is arranged on the side opposite to the tip portion 701b of the pin member 701, but the biasing method is not limited as long as the pin member 701 can be biased in the X direction.

[0056] On the inner peripheral surface of the zoom operation ring 103, there are a protruding tapered portion 103a, a first flat portion (first concave portion) 103b corresponding to the shooting state, a second flat portion (convex portion) 103c corresponding to the retracted state, and a third flat portion (second concave portion) 103d corresponding to the retracted position (retracted end). As shown in FIG. 9(a), when the interchangeable lens 101 is in the shooting state, the tip 701b of the pin member 701 abuts against the abutting portion 109a provided on the fixed cylinder 109. Therefore, the biasing force of the biasing member 702 does not act on the zoom operation ring 103.

[0057] When the zoom operation ring 103 is rotated in the Y direction, the tapered portion 103a of the zoom operation ring 103 and the tapered portion 701a of the pin member 701 come into contact and engage with each other, and the rotation of the zoom operation ring 103 is locked. When the zoom operation ring 103 is further rotated in the Y direction, the pin member 701 moves in the -X direction along the tapered portion 103a, and the tip 701b of the pin member 701 gets over (rides over) the tapered portion 103a. At this time, the biasing force of the biasing member 702 acts on the zoom operation ring 103, which becomes a load on the rotation operation and a click feeling is generated.

[0058] In the click mechanism 700, by changing the angles of the tapered portion 103a and the tapered portion 701a and the biasing force of the biasing member 702, a click feeling suitable for the rotation operation of the zoom operation ring 103 can be arbitrarily set. Due to this click feeling, the user can recognize the boundary of the phase of the zoom operation ring 103 (the boundary between the shooting state and the non-shooting state) from the operation feeling.

[0059] In this embodiment, in the shooting state, the click mechanism 700 locks the rotation of the zoom operation ring 103 in the vicinity of the phase where the holder group 112b contacts the first zoom group 111. Preferably, the rotation phase (position in the direction around the optical axis) at which the rotation of the zoom operation ring 103 is locked by the click mechanism 700 corresponds to the boundary between the shooting state and the non-shooting state. More preferably, the boundary corresponds to one end (wide-angle end or telephoto end) in the shooting state. Also preferably, the necessary torque when the zoom operation ring 103 further rotates from the rotation phase at which the rotation of the zoom operation ring 103 is locked by the click mechanism 700 is smaller than the biasing force of the biasing member 112f.

[0060] Next, with reference to FIGS. 8(a) to 8(d), the relationship between the biasing force of the biasing member 112f, the click timing of the click mechanism 700, and the click biasing force will be described. As shown in FIGS. 8(a) and 8(d), when the interchangeable lens 101 is in the shooting state, the base group 112c and the holder group 112b are biased in a direction away from each other by the biasing member 112f. Therefore, as shown in FIG. 8(c), the tip portion 701b of the pin member 701 is not in contact with the first flat surface portion 103b of the zoom operation ring 103. Therefore, the biasing forces of the biasing member 112f and the biasing member 702 do not act on the operation ring 103.

[0061] Next, when shifting from the shooting state to the non-shooting state, as shown in FIGS. 8(a) and 8(b), since the biasing member 112f is compressed by a drop a, the biasing force of the biasing member 112f increases. At this time, when the biasing force of the biasing member 702 acts on the zoom operation ring 103, it becomes a load on the rotation operation and a click feeling is generated.

[0062] Here, paying attention to the timing of the biasing force of the biasing member 112f and the click biasing force of the click mechanism 700, both increase when shifting from the shooting state to the non-shooting state. For this reason, the timing at which the base group 112c and the holder group 112b constituting the second zoom group 112 approach each other and the timing at which the tip portion 701b of the pin member 701 gets over (rides over) the tapered portion 103a and the click biasing force is generated are synchronized.

[0063] As described above, in this embodiment, the tip 701b of the pin member 701 does not contact the zoom operation ring 103 in the shooting state, and contacts the zoom operation ring 103 by the biasing of the biasing member 702 in the non-shooting state. Preferably, the rotational torque of the zoom operation ring 103 is greater in the non-shooting state than in the shooting state. Also preferably, the biasing force of the biasing member 702 increases as the pin member 701 rides over the tapered portion 103a and weakens at the fully retracted end. Thereby, it is possible to shift the interchangeable lens 101 from the shooting state to the fully retracted state while maintaining a good rotational operation of the zoom operation ring 103.

[0064] In this embodiment, the first zoom group (first group) 111 is disposed closer to the subject side than the second zoom group (second group) 112 having the base group 112c and the holder group 112b, but is not limited thereto. The lens group constituting the first group may be disposed closer to the image plane side than the lens group constituting the second group.

[0065] In this embodiment, when shifting from the shooting state to the non-shooting state, by the action of the cam cylinder and the guide cylinder, the first group moves closer to the second group, and the second group moves closer to the first group, so that the holder group and the first group abut against each other. Therefore, according to this embodiment, it is possible to provide a lens device and an imaging system capable of shortening the overall length without increasing the size.

[0066] The disclosure of each embodiment includes the following configurations. (Configuration 1) A lens device having a first group, a second group, a cam cylinder, and a guide cylinder, wherein the cam cylinder has a first cam groove for moving the first group in the optical axis direction and a second cam groove for moving the second group in the optical axis direction, the guide cylinder has a first guide groove for restricting rotation of the first group around the optical axis and a second guide groove for restricting rotation of the second group around the optical axis, the second group has a base group and a holder group, The holder group is located closer to the first group than the base group in the optical axis direction. When the lens device shifts from the shooting state to the non-shooting state, due to the action of the cam cylinder and the guide cylinder, the first group moves closer to the second group, and the second group moves closer to the first group, so that the holder group and the first group abut against each other. The lens device is characterized by this. (Configuration 2) When the lens device shifts from the shooting state to the non-shooting state, the holder group moves closer to the base group integrally with the first group. The lens device according to Configuration 1 is characterized by this. (Configuration 3) The holder group holds the lens. The base group holds the follower. The lens device according to Configuration 1 or 2 is characterized by this. (Configuration 4) The first group and the second group are characterized in that the distance between them is the closest at one end in the shooting state. The lens device according to any one of Configurations 1 to 3 is characterized by this. (Configuration 5) The one end is a wide-angle end or a telephoto end. The lens device according to Configuration 4 is characterized by this. (Configuration 6) The second group has a first biasing member. The base group and the holder group are biased in a direction away from each other by the first biasing member. The lens device according to any one of Configurations 1 to 5 is characterized by this. (Configuration 7) The biasing force of the first biasing member becomes stronger when the holder group moves to the first position so as to approach the base group integrally with the first group in a state where the holder group abuts against the first group, and becomes weaker as it moves from the first position toward the telephoto end. The lens device according to Configuration 6 is characterized by this. (Configuration 8) The second group has a guide shaft. The holder group moves in the optical axis direction by being guided by the guide shaft. The lens device according to any one of Configurations 1 to 7 is characterized by this. (Configuration 9) an operating member rotatable about an optical axis, and a click mechanism for locking the rotation of the operating member, and the click mechanism locks the rotation of the operating member in the vicinity of a phase where the holder group contacts the first group in the photographing state, the lens device according to any one of Configurations 1 to 8. (Configuration 10) the rotation phase at which the rotation of the operating member is locked by the click mechanism corresponds to a boundary between the photographing state and the non-photographing state, the lens device according to Configuration 9. (Configuration 11) the boundary corresponds to one end in the photographing state, the lens device according to Configuration 10. (Configuration 12) the second group has a first biasing member, and a required torque when the operating member further rotates from a rotation phase at which the rotation of the operating member is locked by the click mechanism is smaller than a biasing force of the first biasing member, the lens device according to any one of Configurations 9 to 11. (Configuration 13) the click mechanism has a concave portion at a position corresponding to a retracted end of the operating member, the lens device according to any one of Configurations 9 to 12. (Configuration 14) the click mechanism includes a fixed cylinder that rotatably holds the operating member about the optical axis, an engaging member movably held by the fixed cylinder, and a second biasing member that biases the engaging member toward the operating member, and the operating member has a tapered portion, and when the engaging member rides on the tapered portion, a click feeling is given to the operating member, the lens device according to any one of Configurations 9 to 13. (Configuration 15) The tip of the engaging member does not contact the operating member in the shooting state, and contacts the operating member by the biasing force of the second biasing member in the non-shooting state. The lens device according to Configuration 14. (Configuration 16) The biasing force of the second biasing member increases when the engaging member rides over the tapered portion and weakens at the fully retracted end. The lens device according to Configuration 14 or 15. (Configuration 17) The rotational torque of the operating member is greater in the non-shooting state than in the shooting state. The lens device according to any one of Configurations 9 to 16. (Configuration 18) The cam cylinder is connected to the operating member. The lens device according to any one of Configurations 9 to 17. (Configuration 19) The guide cylinder is fixed to the lens mount via the fixed cylinder. The lens device according to any one of Configurations 14 to 16. (Configuration 20) The first group is arranged closer to the subject side than the second group. The lens device according to any one of Configurations 1 to 19. (Configuration 21) An imaging system comprising the lens device according to any one of Configurations 1 to 20 and an imaging device.

[0067] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist. Furthermore, each of the above-described embodiments merely shows one embodiment of the present invention, and it is also possible to appropriately combine the embodiments.

Explanation of Reference Numerals

[0068] 101 Interchangeable lens (lens device) 107 Straight guide cylinder (guide cylinder) 107a Straight groove (first guide groove) 107b Straight groove (second guide groove) 108 Cam cylinder 108a Cam groove (first cam groove) 108b Cam groove (second cam groove) 111 First zoom group (first group) 112 Second zoom group (second group) 112b Holder group 112c Base group

Claims

1. A lens device having a first group, a second group, a cam cylinder, and a guide cylinder, wherein the cam cylinder has a first cam groove for moving the first group in the optical axis direction and a second cam groove for moving the second group in the optical axis direction, the guide cylinder has a first guide groove for restricting rotation of the first group around the optical axis and a second guide groove for restricting rotation of the second group around the optical axis, the second group has a base group and a holder group, the holder group is located closer to the first group than the base group in the optical axis direction, when the lens device shifts from the shooting state to the non-shooting state, due to the action of the cam cylinder and the guide cylinder, the first group moves closer to the second group, and the second group moves closer to the first group, so that the holder group and the first group are in contact with each other. A lens device characterized by this.

2. The lens device according to claim 1, wherein when the lens device shifts from the shooting state to the non-shooting state, the holder group moves closer to the base group integrally with the first group.

3. the holder group holds lenses, The lens device according to claim 1, wherein the base group holds followers.

4. The lens device according to claim 1, wherein the first group and the second group are closest to each other at one end in the shooting state.

5. The lens device according to claim 4, wherein the one end is a wide-angle end or a telephoto end.

6. the second group has a first biasing member, The lens device according to claim 1, wherein the base group and the holder group are biased in a direction away from each other by the first biasing member.

7. The biasing force of the first biasing member becomes stronger when the holder group moves to the first position so as to approach the base group integrally with the first group in a state where the holder group is in contact with the first group, and becomes weaker as it moves from the first position toward the retracted end. The lens device according to claim 6, characterized in that.

8. The second group has a guide shaft, The lens device according to claim 1, characterized in that the holder group moves in the optical axis direction by being guided by the guide shaft.

9. An operation member rotatable around the optical axis, And a click mechanism for locking the rotation of the operation member, The click mechanism locks the rotation of the operation member in the vicinity of the phase where the holder group contacts the first group in the photographing state. The lens device according to any one of claims 1 to 8, characterized in that.

10. The rotation phase at which the rotation of the operation member is locked by the click mechanism corresponds to the boundary between the photographing state and the non-photographing state. The lens device according to claim 9, characterized in that.

11. The boundary corresponds to one end in the photographing state. The lens device according to claim 10, characterized in that.

12. The second group has a first biasing member, The required torque when the operation member further rotates from the rotation phase at which the rotation of the operation member is locked by the click mechanism is smaller than the biasing force of the first biasing member. The lens device according to claim 9, characterized in that.

13. The click mechanism has a concave portion at a position corresponding to the retracted end of the operation member. The lens device according to claim 9, characterized in that.

14. The click mechanism, A fixed cylinder that rotatably holds the operation member around the optical axis, An engaging member movably held in the fixed cylinder, and a second biasing member that biases the engaging member toward the operating member. The operating member has a tapered portion. The lens device according to claim 9, wherein a click feeling is imparted to the operating member when the engaging member rides on the tapered portion.

15. The lens device according to claim 14, wherein a tip portion of the engaging member does not contact the operating member in the shooting state, and contacts the operating member by the biasing force of the second biasing member in the non-shooting state.

16. The lens device according to claim 14, wherein the biasing force of the second biasing member increases when the engaging member rides on the tapered portion and weakens at the fully retracted end.

17. The lens device according to claim 9, wherein the rotational torque of the operating member is greater in the non-shooting state than in the shooting state.

18. The lens device according to claim 9, wherein the cam cylinder is connected to the operating member.

19. The lens device according to claim 14, wherein the guide cylinder is fixed to the lens mount via the fixed cylinder.

20. The lens device according to any one of claims 1 to 8, wherein the first group is disposed closer to the subject side than the second group.

21. An imaging system comprising the lens device according to any one of claims 1 to 8 and an imaging device.

Images