Lens device and imaging apparatus

Abstract

To provide a lens device that can prevent a deterioration in image quality due to a change of posture.SOLUTION: A lens device (101) has: a cam barrel (108) that has a first cam groove (108a) and a second cam groove (108b) formed, and rotates around an optical axis; a first holding member (402) that includes a first cam follower (403) engaged with the first cam groove, and moves along the optical axis according to the rotation of the cam barrel; a second holding member (610) that includes a second cam follower (613) engaged with the second cam groove, and moves along the optical axis according to the rotation of the cam barrel; a first guide member (511) that guides the first holding member movably along the optical axis; and a first urging member (404) that urges the first holding member in an optical axis direction. The width of the first cam groove is larger than the width of the first cam follower. The first urging member is held by the first holding member and the second holding member.SELECTED DRAWING: Figure 7

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a lens barrel (lens device) having an adjustment mechanism for adjusting the tilt of a lens.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the lens device disclosed in Patent Document 1, it is difficult to suppress the relative tilting of a plurality of lenses at another zoom position while suppressing the relative tilting of a plurality of lenses at a predetermined zoom position.

[0005] Further, for example, when the user tries to shoot upward or downward and the posture of the lens device changes, the interval between a plurality of lenses fluctuates, which may cause image degradation.

[0006] Therefore, an object of the present invention is to provide a lens device capable of suppressing degradation of image quality due to a change in posture.

Means for Solving the Problems

[0007] As one aspect of the present invention, a lens device includes a cam cylinder in which a first cam groove and a second cam groove are formed and which rotates around an optical axis, a first cam follower engaged with the first cam groove, a first holding member that moves along the optical axis in response to the rotation of the cam cylinder, a second cam follower engaged with the second cam groove, a second holding member that moves along the optical axis in response to the rotation of the cam cylinder, a first guide member that guides the first holding member so as to be movable along the optical axis, and a first biasing member that biases the first holding member in the optical axis direction. The width of the first cam groove is larger than the width of the first cam follower, and the first biasing member is held by the first holding member and the second holding member.

[0008] Other objects and features of the present invention will be described in the following embodiments.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a lens device capable of suppressing deterioration of image quality due to a change in posture.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0011] 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 a lens-integrated camera.

[0012] First, referring to FIGS. 1(a) and 1(b), the imaging device (imaging system) 100 in this embodiment will be described. FIGS. 1(a) and 1(b) are external perspective views of the imaging device 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, which is the direction in which the optical axis OA of the imaging optical system accommodated in the interchangeable lens 101 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. Also, 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 orthogonal axes, the Z-axis and the Y-axis.

[0013] The imaging device 100 includes a camera body (digital camera, imaging device body) 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 it is also applicable to an imaging device in which the camera body and the lens device are integrally configured.

[0014] 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 to enter 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.

[0015] 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 videos. Also, by the user pressing the release button 5 halfway, 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.

[0016] 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.

[0017] An imaging optical system that forms a subject image by imaging light from a subject is housed inside 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 take a picture 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.

[0018] 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 an 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.

[0019] Next, with reference to FIG. 2, the electrical and optical configurations of the imaging device 100 will be described. FIG. 2 is a block diagram of the imaging device 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 control of the entire system of the camera body 1 and the interchangeable lens 101 in the present 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 entire system of the camera body 1 and the interchangeable lens 101 is controlled by operating both in cooperation.

[0020] 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.

[0021] The imaging optical system included in the interchangeable lens 101 is connected to a 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 that includes 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 that includes 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.

[0022] 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 in 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 image recorded in the storage unit 13 or a recording medium (not shown).

[0023] The camera control unit 12 controls the focus drive unit 601 according to a shooting preparation operation (such as a half-press operation of the release button 5) at the operation unit 11. For example, when the 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 about 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.

[0024] 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 be adopted. Also, 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.

[0025] The camera control unit 12 controls the driving of the aperture group 301 and the shutter unit 14 via the aperture drive unit 302 and the shutter drive unit 15 according to the set value of the aperture 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 aperture 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 device 16.

[0026] 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 caused by the user's hand shake or the like. The pitch shake detection unit 19 and the yaw shake detection unit 20 respectively use an angular velocity sensor (vibration gyro) or an angular acceleration sensor to detect image shake in the pitch direction (rotation direction around the Z axis) and the yaw direction (rotation direction around the Y axis) and output a shake signal.

[0027] 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 position in the pitch / yaw direction, and reduces image blur during exposure and during through-image display.

[0028] 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.

[0029] 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.

[0030] 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 housed state (a state in the retracted barrel position) when not in use. Also, FIG. 5 shows the retracted barrel end with the shortest overall length in the optical axis direction.

[0031] 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 moves 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 this embodiment, the state where imaging by the imaging optical system is possible is defined as the imaging state, and the state where the imaging optical system is in the telescopic position is defined as the telescopic state. Note that the state where imaging is possible means that the functions of the imaging device 100 including the camera body 1 and the interchangeable lens 101 can always operate normally. That imaging is restricted means that at least a part of the functions of the imaging device 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 act of imaging itself (e.g., pressing the shutter to capture a subject) is possible, but due to events such as the focus of the captured image not being in focus, the whole or a part of the image may become blurred.

[0032] As shown in Figs. 3 and 4, in this 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 this 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.

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

[0034] On the straight-ahead guide tube 107, straight-ahead guide grooves are formed at equally spaced positions to restrict the movement of the zoom group 110 in the rotational direction and guide the straight-ahead movement in the optical axis direction. Also, on the cam tube 108, corresponding to the zoom group 110, cam grooves having trajectories at different angles in the rotational direction are formed at the same equally spaced positions. 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 rotational direction due to the engagement between the straight-ahead guide groove and the cam groove.

[0035] The interchangeable lens 101 of the present embodiment has a retracting mechanism. By the retracting mechanism, it becomes possible to further retract the zoom group 110 toward 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 when not shooting, 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 state where shooting as shown in FIG. 3 is possible.

[0037] Next, with reference to FIGS. 6 and 7, the rear group unit 600 of the interchangeable lens 101 will be described. FIG. 6 is a perspective view of the rear group unit 600 as seen from the front side (subject side). FIG. 7 is an exploded perspective view of a part of the members (components) constituting the rear group unit 600 shown in FIG. 6.

[0038] The rear group unit 600 has a moving cylinder (second holding member) 610. The fourth zoom group 114 and the fifth zoom group 115 are housed inside the moving cylinder 610. The fourth zoom group 114 is configured to include a fourth lens 401 and a fourth lens holding frame (first holding member) 402 that holds the fourth lens 401. The fifth zoom group 115 is configured to include a fifth lens 501 and a fifth lens holding frame 502 that holds the fifth lens 501.

[0039] The fourth lens holding frame 402 has a sleeve portion 402a and an anti-vibration portion 402b. The sleeve portion 402a is slidably fitted with a main guide (guide member, first guide member) 511 arranged substantially parallel to the optical axis OA. The main guide 511 guides the fourth lens holding frame 402 to be movable along the optical axis OA. The anti-vibration portion 402b is slidably fitted with a sub-guide (sub-guide member, second guide member) 512 arranged substantially parallel to the main guide 511. The sub-guide 512 restricts the movement of the fourth lens holding frame 402 in the rotational direction around the optical axis OA.

[0040] Both axial ends of each of the main guide 511 and the sub-guide 512 are supported by the moving cylinder 610 and the guide cap 513. The guide cap 513 is fixed to the moving cylinder 610. With such a configuration, the fourth zoom group 114 is positioned in the Y-axis direction and the Z-axis direction by the main guide 511 and the sub-guide 512. The fourth zoom group 114 can move smoothly in the optical axis direction (X-axis direction) between the moving cylinder 610 and the guide cap 513.

[0041] In this embodiment, as an example of the guide member and the sub-guide member, shaft-like members (main guide 511, sub-guide 512) are shown, but the present invention is not limited thereto. As long as it is a member that can guide in the optical axis direction, a plate-like member, a wire member, or the like may be adopted as the guide member and the sub-guide member. Further, in this embodiment, the main guide 511 is inserted into the fourth lens holding frame 402 and held by the moving cylinder 610 and the guide cap 513, but the present invention is not limited thereto. Conversely, the main guide 511 may be inserted into the moving cylinder 610 and held by the fourth lens holding frame 402.

[0042] On the outer peripheral surface of the fifth lens holding frame 502, three first rollers 514 and three second rollers 515 are provided at 120° equally divided positions. The first rollers 514 and the second rollers 515 are respectively engaged with the openings of the moving cylinder 610. The first rollers 514 and the second rollers 515 are eccentric, and the eccentricity and thrust adjustment of the fifth zoom group 115 are possible.

[0043] On the outer peripheral surface of the moving cylinder 610, three moving rollers (second cam followers) 613 are provided at equally divided positions. As described above, the moving rollers 613 are respectively fitted (engaged) with the corresponding linear guide grooves and the second cam grooves 108b described later. Then, for example, when zooming from the wide-angle end to the telephoto end, the cam cylinder 108 rotates, and the moving cylinder 610 moves straight in the optical axis direction integrally with components such as the fourth zoom group 114 in accordance with the rotation of the cam cylinder 108.

[0044] Next, with reference to FIGS. 8(a) and 8(b), the fourth zoom group 114 will be described in detail. FIGS. 8(a) and 8(b) are perspective views seen from the front side (object side) of the fourth zoom group 114. FIG. 8(a) shows the side surface on which the second biasing member 405 is disposed. FIG. 8(b) shows the side surface on which the first biasing member 404 is disposed.

[0045] Specifically, although described in detail later, the fourth lens holding frame 402 has one eccentric roller (first cam follower) 403 that engages with a first cam groove 108a formed in the cam cylinder 108. The eccentric roller 403 can adjust the fourth lens holding frame 402 in the optical axis direction. As described above, the fourth lens holding frame 402 is positioned by the main guide 511 and the sub-guide 512, thereby suppressing relative tilting with the moving cylinder 610. For this reason, when there is no minute gap (play) between the first cam groove 108a formed in the cam cylinder 108 and the eccentric roller 403, multiple fitting occurs with the main guide 511 and the sub-guide 512. As a result, the fourth lens holding frame 402 is deformed, or the slidability with the main guide 511 is reduced. Therefore, in the present embodiment, by making the width of the first cam groove 108a larger than the width (outer diameter) of the eccentric roller 403, play is provided between the first cam groove 108a and the eccentric roller 403.

[0046] On the other hand, when such play exists, for example, when the user tries to take a picture in an upward or downward posture position and the posture of the interchangeable lens 101 changes, the eccentric roller 403 may inadvertently move within the range of the play with the first cam groove 108a under the action of gravity or the like. For this reason, in the present embodiment, a first biasing member 404 is disposed between the fourth lens holding frame 402 and the moving cylinder 610. That is, the first biasing member 404 is held by the fourth lens holding frame 402 and the moving cylinder 610. The first biasing member 404 biases the fourth lens holding frame 402 in the optical axis direction with respect to the moving cylinder 610. Although the first biasing member 404 is a spring member, it is not limited thereto, and other elastic members such as rubber members may be used.

[0047] In the present embodiment, the biasing force of the first biasing member 404 is set to be greater than the sum of the weight of the fourth lens holding frame 402 and the weight of the fourth lens 401. As a result, the fourth lens holding frame 402 is always in a state of being snugly fitted against the action of gravity, and it is possible to accurately determine the distance (spacing) in the optical axis direction between the fourth lens 401 and the fifth lens 501.

[0048] Also, a second biasing member 405 is disposed between the fourth lens holding frame 402 and the moving cylinder 610. The second biasing member 405 biases the fourth lens holding frame 402 with respect to the sub-guide 512. More specifically, the second biasing member 405 generates a moment around the main guide 511 on the fourth lens holding frame 402 and biases the vibration damping portion 402b with respect to the sub-guide 512. As a result, the fourth lens holding frame 402 is always in a state of being snugly fitted, and it is possible to accurately determine the position of the fourth lens 401 in the decentering direction. An introduction portion 405a having an inclined shape with respect to the optical axis direction is provided at the tip of the second biasing member 405. When inserting the fourth zoom group 114 (the fourth lens holding frame 402) into the moving cylinder 610, the second biasing member 405 can enter following it, so that it can be inserted straight in the optical axis direction.

[0049] FIG. 9(a) is a side view of a component including the rear group unit 600, the straight guide cylinder 107, and the cam cylinder 108 of the present embodiment. FIG. 9(b) is a cross-sectional view taken along line A-A in FIG. 9(a). FIG. 9(c) is an enlarged view of region B in FIG. 9(b). As shown in FIG. 9(c), the fourth lens holding frame 402 is provided with a rear contact portion (contact portion) 402c that contacts the straight guide cylinder 107 when the interchangeable lens 101 receives an external impact.

[0050] As shown in FIGS. 9(b) and 9(c), when projected onto the image plane from a direction parallel to the optical axis OA, the distance between the first biasing member 404 serving as the force point and the eccentric roller 403 serving as the fulcrum is shorter than the distance between the first biasing member 404 serving as the force point and the main guide 511 serving as the acting point. In this way, by bringing the fulcrum closer to the force point than the acting point, the generation of unnecessary moments can be suppressed.

[0051] Similarly, when projected onto the image plane from a direction parallel to the optical axis OA, the distance between the main guide 511 and the second biasing member 405 is longer than the distance between the main guide 511 and the eccentric roller 403. As a result, it becomes possible to generate a moment around the main guide 511 with a relatively small load, and the sub-guide 512 can be efficiently rattled.

[0052] Also, when projected onto the image plane from a direction parallel to the optical axis OA, the distance between the main guide 511 and the sub-guide 512 is longer than the distance between the main guide 511 and the second biasing member 405. That is, among the components constituting the fourth zoom group 114, the distance between the main guide 511 and the sub-guide 512 is the longest (the farthest apart), so that stable movement is possible without impairing the positional accuracy of the fourth lens 401 even during zooming.

[0053] FIG. 10 is a bottom view showing the components shown in FIG. 9(a) from the lower side in the Y-axis direction. The cam cylinder 108 is formed with a first cam groove 108a and a second cam groove 108b. The first cam groove 108a and the second cam groove 108b have different trajectories. The first cam groove 108a is a single groove formed corresponding to the eccentric roller 403. The second cam groove 108b is three grooves formed at equal positions corresponding to the moving roller 613.

[0054] Figs. 11(a) and 11(b) are enlarged views of the main part of the first cam groove 108a shown in Fig. 10. Fig. 11(a) shows the first cam groove 108a at the wide-angle end, and Fig. 11(b) shows the first cam groove 108a at the telephoto end. The eccentric roller 403 can adjust the fourth lens holding frame 402 in the optical axis direction. The locus of the first cam groove 108a is a non-linear cam with different angles at the wide-angle end and the telephoto end. Therefore, as shown in Figs. 11(a) and 11(b), the contact position of the eccentric roller 403 with the first cam groove 108a changes according to the rotation of the cam cylinder 108. In this way, although the adjustment amount of the fourth lens holding frame 402 in the optical axis direction changes between the wide-angle end and the telephoto end, the provided washer 406 can reduce the change amount of the adjustment amount.

[0055] Fig. 12 is a cross-sectional view of the fourth zoom group 114 in the present embodiment. The washer (adjustment member) 406 is a sheet member with a constant thickness and is disposed between the fourth lens holding frame 402 and the fourth lens 401. By changing the presence or absence or the thickness of the washer 406, it is possible to adjust the interval (distance) in the optical axis direction between the fourth lens 401 and the fifth lens 501. The maximum amount adjustable by the eccentric roller 403 is smaller than the maximum amount adjustable by the washer 406.

[0056] When adjusting using the washer 406, the adjustment amount at each zoom position does not change, but continuous adjustment is impossible and there is a limit to the adjustment accuracy. Therefore, by using in combination the adjustment by the eccentric roller 403 that enables continuous adjustment, high-precision adjustment becomes possible. Thereby, even if the locus of the first cam groove 108a is a non-linear cam, the adjustment error can be suppressed.

[0057] According to the present embodiment, it is possible to provide a lens device and an imaging device that can reduce the relative tilt and the variation in the interval between the fourth lens 401 and the fifth lens 501 at each zoom position, and suppress the deterioration of the image quality due to the change in posture.

[0058] The disclosure of each example includes the following configurations. (Configuration 1) A first cam groove and a second cam groove are formed, and a cam cylinder that rotates around an optical axis, a first cam follower that engages with the first cam groove, and a first holding member that moves along the optical axis in accordance with the rotation of the cam cylinder, a second cam follower that engages with the second cam groove, and a second holding member that moves along the optical axis in accordance with the rotation of the cam cylinder, a first guide member that guides the first holding member so as to be movable along the optical axis, a first biasing member that biases the first holding member in the optical axis direction, and having, the width of the first cam groove is larger than the width of the first cam follower, the first biasing member is held by the first holding member and the second holding member, a lens device characterized by that. (Configuration 2) The lens device according to Configuration 1, wherein the first guide member is held by the first holding member and inserted into the second holding member. (Configuration 3) The lens device according to Configuration 1, wherein the first guide member is held by the second holding member and inserted into the first holding member. (Configuration 4) When projected from a direction parallel to the optical axis onto an image plane, the distance between the first biasing member and the first cam follower is shorter than the distance between the first biasing member and the first guide member, the lens device according to any one of Configurations 1 to 3. (Configuration 5) further having a lens held by the first holding member, the biasing force of the first biasing member is larger than the sum of the weight of the first holding member and the weight of the lens, the lens device according to any one of Configurations 1 to 4. (Configuration 6) The first cam follower is an eccentric roller capable of adjusting the first holding member in the optical axis direction, the lens device according to any one of Configurations 1 to 5. (Configuration 7) The lens device according to configuration 6, wherein the eccentric roller has a contact position with the first cam groove that changes in accordance with the rotation of the cam cylinder. (Configuration 8) The lens device according to configuration 5, further comprising an adjustment member disposed between the first holding member and the lens and adjusting a distance in the optical axis direction between the first holding member and the lens. (Configuration 9) The lens device according to configuration 8, wherein a maximum amount adjustable by the eccentric roller is smaller than a maximum amount adjustable by the adjustment member. (Configuration 10) A second guide member that restricts movement of the first holding member in a rotational direction around the optical axis, The lens device according to any one of configurations 1 to 9, further comprising a second biasing member that biases the first holding member with respect to the second guide member. (Configuration 11) The lens device according to configuration 10, wherein the second biasing member has an introduction portion having an oblique shape with respect to the optical axis direction. (Configuration 12) When projected from a direction parallel to the optical axis onto the image plane, a distance between the first guide member and the second biasing member is longer than a distance between the first guide member and the first cam follower. The lens device according to configuration 10. (Configuration 13) When projected from a direction parallel to the optical axis onto the image plane, a distance between the first guide member and the second guide member is longer than a distance between the first guide member and the second biasing member. The lens device according to configuration 10 or 11. (Configuration 14) The lens device further comprises a guide cylinder disposed inside the cam cylinder, The lens device according to any one of configurations 1 to 13, wherein the first holding member has a contact portion that contacts the guide cylinder when the lens device receives an impact from the outside. (Configuration 15) An imaging device comprising the lens device according to any one of configurations 1 to 4 and an imaging element.

[0059] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof. 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 with each other.

Explanation of Reference Numerals

[0060] 101 Interchangeable lens (lens device) 108 Cam barrel 108a First cam groove 108b Second cam groove 402 Fourth lens holding frame (first holding member) 403 Eccentric roller (first cam follower) 404 First biasing member 511 Main guide (first guide member) 610 Moving cylinder (second holding member) 613 Moving roller (second cam follower)

Claims

1. A cam cylinder in which a first cam groove and a second cam groove are formed and which rotates around an optical axis, a first holding member including a first cam follower engaged with the first cam groove and moving along the optical axis in response to rotation of the cam cylinder, a second holding member including a second cam follower engaged with the second cam groove and moving along the optical axis in response to rotation of the cam cylinder, a first guide member guiding the first holding member to be movable along the optical axis, a first biasing member biasing the first holding member in the optical axis direction, and having wherein a width of the first cam groove is larger than a width of the first cam follower, the first biasing member is held by the first holding member and the second holding member, a lens device.

2. The lens device according to claim 1, wherein the first guide member is held by the first holding member and inserted through the second holding member.

3. The lens device according to claim 1, wherein the first guide member is held by the second holding member and inserted through the first holding member.

4. When projected onto an image plane from a direction parallel to the optical axis, a distance between the first biasing member and the first cam follower is shorter than a distance between the first biasing member and the first guide member, the lens device according to claim 1.

5. further including a lens held by the first holding member, wherein a biasing force of the first biasing member is larger than a sum of a weight of the first holding member and a weight of the lens, the lens device according to any one of claims 1 to 4.

6. The first cam follower is an eccentric roller capable of adjusting the first holding member in the optical axis direction, the lens device according to any one of claims 1 to 4.

7. The eccentric roller, wherein a contact position with the first cam groove changes in response to rotation of the cam cylinder, the lens device according to claim 6.

8. The lens device according to claim 5, further including an adjustment member disposed between the first holding member and the lens and adjusting a distance in the optical axis direction between the first holding member and the lens.

9. The lens device according to claim 8, wherein a maximum amount adjustable by the eccentric roller is smaller than a maximum amount adjustable by the adjustment member.

10. A second guide member that restricts movement of the first holding member in the rotational direction around the optical axis; The lens device according to any one of claims 1 to 4, further comprising a second biasing member that biases the first holding member with respect to the second guide member.

11. The lens device according to claim 10, wherein the second biasing member has an introduction portion having an oblique shape with respect to the optical axis direction.

12. When projected onto the image plane from a direction parallel to the optical axis, the distance between the first guide member and the second biasing member is longer than the distance between the first guide member and the first cam follower. The lens device according to claim 10, characterized in that.

13. When projected onto the image plane from a direction parallel to the optical axis, the distance between the first guide member and the second guide member is longer than the distance between the first guide member and the second biasing member. The lens device according to claim 10, characterized in that.

14. Further comprising a guide cylinder disposed inside the cam cylinder, The lens device according to any one of claims 1 to 4, wherein the first holding member has a contact portion that contacts the guide cylinder when the lens device receives an impact from the outside.

15. An imaging device comprising the lens device according to any one of claims 1 to 4 and an imaging element.

Images