JP7102201B2 - Lens device and imaging device - Google Patents

Description

The present invention relates to a lens device that moves a lens unit by using a rotational force generated by a drive source.

As the lens device as described above, as disclosed in Patent Document 1, the rotation of the rotating body (rotor) of the drive source (vibration type motor) is transmitted to the drive ring (cam ring), and the drive ring Some have a configuration that converts rotation into movement of the lens unit in the optical axis direction. In the lens device of Patent Document 1, the rotation position (or rotation amount) of the drive ring corresponding to the position of the lens unit in the optical axis direction is detected by the encoder.

More specifically, in the lens device of Patent Document 1, the rotation of the rotating body is taken out by an output member (drive ring), and a transmission portion provided on the output member is an optical axis on a transmitted portion provided on the drive ring. Rotation is transmitted from the output member to the drive ring by engaging in the rotational direction. Further, the scale and the sensor head of the encoder are attached to the inner peripheral surface of the output member and the outer peripheral surface of the base member (drive base), respectively.

Japanese Unexamined Patent Publication No. 2015-114441

However, if there is play in the direction around the optical axis between the transmission portion of the output member and the transmitted portion of the drive ring, the position of the scale attached to the output member shifts with respect to the drive ring in that direction. Therefore, an error occurs in the rotation position of the drive ring detected by the encoder, that is, the detection position of the lens unit.

The above-mentioned backlash can be reduced by urging the drive ring with respect to the output member by an urging member such as a spring in the direction around the optical axis, but for that purpose, the drive ring that drives the lens unit is used. It is necessary to have an urging force to overcome the load that rotates the lens. In the first place, the play is provided for the purpose of absorbing the axial deviation between the output member and the drive ring. However, if the urging force is large, the axial deviation cannot be absorbed.

The present invention provides a lens device capable of reducing a detection error of a rotation position of a drive ring by an encoder, and an imaging device including the lens device.

The lens device as one aspect of the present invention includes a lens unit that can move in the optical axis direction, a drive source that generates a rotational force in the optical axis direction, and a lens unit that rotates in the optical axis direction to rotate the lens unit in the optical axis direction. A drive ring to be moved to, an encoder provided to detect the rotation position of the drive ring, a fixed ring holding one of the scale and the sensor constituting the encoder, and a transmission rotating in the direction around the optical axis. It has a transmitted part to which rotation is transmitted from the part, holds the other of the scale and the sensor and can rotate in the direction around the optical axis, and presses the transmitted part against the transmitted part in the direction around the optical axis. In addition, a first urging member that urges the holding ring to one side in the optical axis direction, and the holding ring in the optical axis direction in order to position the holding ring with respect to the fixed ring in the optical axis direction. One of the holding ring in the radial direction with respect to the fixed ring in order to position the holding ring with respect to the fixed ring in the radial direction orthogonal to the optical axis direction with the second urging member urging on one side. It has a third urging member that urges the side. The drive ring then receives the rotational force directly from the drive source or via a connecting member fixed to the drive ring. The transmission unit is provided on the drive ring or the connecting member.

An imaging device provided with the lens device also constitutes another aspect of the present invention.

According to the present invention, one of the scale and the sensor is held by the base ring, and the other is held by the holding ring that does not apply a load for rotating the drive ring, so that the error in detecting the rotation position of the drive ring by the encoder can be reduced. Can be done.

The figure which shows the structure of the interchangeable lens and the camera which is Example 1 of this invention. FIG. 5 is a cross-sectional view of a focus drive unit in the interchangeable lens of the first embodiment. Another sectional view of the focus drive unit. Yet another cross-sectional view of the focus drive unit. The perspective view of the focus drive unit. The top view which shows the connecting part in the said focus drive unit. The figure explaining the encoder in Example 1. FIG. The figure explaining the scale of the said encoder. The figure which shows the detection signal output from the sensor head of the said encoder. The figure explaining the principle of the absolute position detection by the encoder in Example 1. FIG. The perspective view which shows the guide roller in Example 1. FIG.

Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of a camera system including an interchangeable lens 101 as a lens device according to an embodiment of the present invention and a camera 201 to which the interchangeable lens 101 is detachably attached. The interchangeable lens 101 is attached to the camera 201 via the mount 111.

The interchangeable lens 101 includes an imaging optical system including a first fixed lens 102a, a focus lens 103, an aperture unit 104, an anti-vibration lens 105, and a second fixed lens 102b arranged in order from the subject side. The imaging optical system has an optical axis x. In the following description, the direction in which the optical axis x extends is referred to as the optical axis direction, and the radial direction orthogonal to the optical axis direction is referred to as the radial direction. Further, the interchangeable lens 101 includes a gyro sensor 106 that detects lens shake due to camera shake and the like, and a lens CPU 107 that controls and processes the interchangeable lens 101.

The lens CPU 107 controls the focus drive source 110 and the aperture drive source 109 to move the focus lens 103 in the optical axis direction or change the aperture aperture diameter of the aperture unit 104. Further, the lens CPU 107 calculates the amount of lens runout using the runout detection signal from the gyro sensor 106. Then, in order to reduce the image shake according to the lens shake amount, the vibration isolation lens 105 is shift-driven in the y direction (yaw direction) and the p direction (pitch direction) orthogonal to the optical axis x. (IS) Controls the drive source 108.

The camera 201 has an image pickup device 202 that captures (photoelectrically converts) a subject image formed by a light flux that has passed through an imaging optical system. The camera CPU 203 includes a release button 204, a main power supply 205, and an image recording medium 206.

When the release button 204 is half-pressed and the first switch SW1 is turned on, the camera CPU 203 starts imaging preparation operations such as photometric operation, autofocus operation, and vibration isolation operation. Further, when the release button 204 is fully pressed and the second switch SW2 is turned on, the camera CPU 203 performs recording imaging to generate an captured image, and records the captured image on the image recording medium 206.

The camera CPU 203 communicates with the lens CPU 107 via a communication contact (not shown) provided on the mount 111. The main power supply 205 supplies power to the interchangeable lens 101 via a power supply contact (not shown) provided on the mount 111.

The configuration of the focus drive unit 320 provided in the interchangeable lens 101 will be described with reference to FIGS. 2, 3, 4, 5, and 6. 2, 3 and 4, respectively, show cross sections of the focus drive unit 320 cut at different positions in the direction around the optical axis (hereinafter, also referred to as the circumferential direction).

The base ring 325 as a fixed ring is a ring as a focus drive source 110 in order from the image side (first side) to the subject side (second side) in the optical axis direction in the outer peripheral portion which is the outer peripheral portion in the radial direction. It holds a vibrating motor and a scale ring 326. Further, inside the base ring 325 in the radial direction, a focus lens unit composed of a cam ring (drive ring) 322, a guide tube (lens barrel member) 321, a focus lens 103, and a focus holding frame 312 for holding the focus lens 103. And are arranged. The guide tube 321 is a fixed lens barrel integrally coupled to the base ring 325. A cam ring 322 is rotatably arranged in the circumferential direction between the guide cylinder 321 and the base ring 325. Further, the portion of the guide cylinder 321 on the subject side is projected outward in the radial direction of the base ring 325 in a flange shape.

Cam follower pins 312a are provided at three locations in the circumferential direction of the focus holding frame 312. Straight groove portions 321a extending in the optical axis direction are provided at three locations in the circumferential direction of the guide cylinder 321. Each cam follower pin 312a is engaged with each straight groove portion 321a. As a result, the focus holding frame 312 is guided in the optical axis direction.

The cam ring 322 arranged on the radial outer side of the guide cylinder 321 is rotatable in the circumferential direction. The cam ring 322 is provided with three cam groove portions 322a to which the three cam follower pins 312a are engaged with each other. When the cam ring 322 rotates in the circumferential direction, the focus holding frame 312 moves in the optical axis direction due to the cam action on each cam follower pin 312a of each cam groove portion 322a.

The vibrating motor has a stator 332 as a vibrating body composed of a piezoelectric element (electrical-mechanical energy conversion element) and an elastic body, and a rotor 331 as a rotating body in contact with the elastic body of the stator 332. The stator 332 is held by a stator holding ring 370, and the stator holding ring 370 is integrally coupled with the base ring 325.

Further, the vibration type motor has a pressure spring (pressurizing urging member) 353 that urges the stator 332 from the image side to the subject side to bring it into pressure contact with the rotor 331. When a periodic signal such as two pulse signals having different phases is applied to the piezoelectric element, the piezoelectric element is periodically deformed and vibration (elliptical motion or the like) is excited on the surface of the stator 332. The rotor 331, which is in pressure contact with the stator 332 excited by the vibration, is rotationally driven in the direction around the optical axis. That is, a rotational force is generated from the vibrating motor.

The rotor 331 is integrally rotatably coupled to the interlocking ring 330 in the circumferential direction by the adhesive force of the rubber ring 333. The interlocking ring 330 is integrally rotatably coupled to the cam ring 322 by the adhesive force of the rubber ring 352 in the circumferential direction. That is, the rotor 331, the interlocking ring 330, and the cam ring 322 rotate integrally.

The scale ring (holding ring) 326 is rotatable in the circumferential direction with respect to the base ring 325. The scale ring 326 has a key portion (transmitted portion) 326a extending toward the image side at one location (or a plurality of locations) in the circumferential direction thereof. As shown in FIGS. 5 and 6, the key portion 326a is engaged with the recess (transmission portion) 330a formed in the interlocking ring 330. The circumferential width of the recess 3 30 a is larger than that of the key portion 326 a. That is, a play in the circumferential direction is originally provided between the key portion 326a and the recess 330a.

A leaf spring 354 as a first urging member is fixed to the scale ring 326 by a screw. The scale ring 326 is urged to one side (lower side in FIG. 6) in the circumferential direction by a reaction force generated when the leaf spring 354 abuts on the convex portion 330b adjacent to the concave portion 330a in the interlocking ring 330. .. As a result, the key portion 326a abuts (presses) the inner surface of the recess 330a in the circumferential direction. In other words, the convex portion 330b of the interlocking ring 330 is sandwiched between the key portion 326a and the leaf spring 354. With this configuration, even if there is an axial deviation between the interlocking ring 330 (that is, the cam ring 322) and the scale ring 326, the axial deviation is absorbed by the deformation of the leaf spring 354. Further, even when the rotation direction of the vibration type motor, that is, the rotation direction of the interlocking ring 330 is reversed, the scale ring 326 does not delay the interlocking ring 330 by the amount of play between the key portion 326a and the recess 330a. The direction of rotation can be reversed integrally.

Near the image-side ends of the guide cylinder 321 and the cam ring 322, radial ball bearings including a plurality of balls 350 arranged in the circumferential direction are provided. The ball 350 as a rotatable rotating member is a steel ball. As a configuration of the radial ball bearing portion, the guide cylinder 321 is formed with a ball race surface 321b as a surface inclined by 45 ° with respect to the optical axis x and as a first contact surface facing the image side and the outer side in the radial direction. Has been done. Further, the cam ring 322 has a ball race surface 322b as a second contact surface which is inclined by 45 ° with respect to the optical axis x and faces the object side and the inner side in the radial direction, and the image side and the diameter. A ball race surface 322c is formed as a third contact surface facing inward in the direction. The ball race surface 322b of the cam ring 322 is located on the side opposite to the ball race surface 321b of the guide cylinder 321 with the ball 350 interposed therebetween.

Further, the female screw portion 351a of the ball race member 351 as a ring member is screwed from the image side to the male screw portion 321c provided on the outer periphery of the end portion of the guide cylinder 321 on the image side. The ball race member 351 is formed with a ball race surface 351a which is a surface inclined by 45 ° with respect to the optical axis x and serves as a fourth contact surface facing the object side and the outer side in the radial direction. The ball race surface 351a of the ball race member 351 is located on the side opposite to the ball race surface 322c of the cam ring 322 with the ball 350 interposed therebetween.

Before attaching the ball race member 351 to the guide cylinder 321, the ball 350 is inserted between the three ball race surfaces 321b, 322b, 322c, and then the female screw portion 351a of the ball race member 351 is inserted into the male screw portion 321c of the guide cylinder 321. Screw in and tighten. As a result, the ball 350 comes into contact with the four ball race surfaces 321b, 322b, 322c, and 351a and is held so as to be rollable in the circumferential direction. With this configuration, the cam ring 322 is held without play in the optical axis direction with respect to the guide cylinder 321 and can rotate in the circumferential direction at a fixed position in the optical axis direction.

The pressure spring 353 described above urges the stator 332 in the left direction (subject side) in FIG. Then, the urging force is transmitted to the stator 332, the rotor 331, the interlocking ring 330, the cam ring 322, and the ball 350, and is received by the guide tube 321 which is a lens barrel member fixed to the base ring 325 on the ball race surface 321b. Be done. Therefore, the pressure spring 353 also has a role of shifting the cam ring 322 to the guide cylinder 321 at the same time as generating the pressing force between the stator 332 and the rotor 331, which is necessary for the vibration type motor. As a result, it is possible to suppress (that is, position) the backlash of the cam ring 322 with respect to the guide cylinder 321 in the optical axis direction and the radial direction, and as a result, the position accuracy of the focus lens unit in the optical axis direction due to the backlash. It is possible to prevent a decrease in the lens and displacement in the radial direction.

Further, since the pressurization in the vibration type motor and the offsetting of the cam ring 322 are performed by the same pressure spring 353, the number of parts can be reduced as compared with the case where these are performed by using separate urging members. The focus drive unit and the interchangeable lens 101 can be miniaturized.

In this embodiment, the radial ball bearing portion is provided on the image side of the cam ring 322 on the subject side and inside the stator 332 and the rotor 331 in the radial direction. More specifically, the radial ball bearing portion is provided on the image side of the rotor 331. Furthermore, at least a part of the radial ball bearing portion is provided within the range in which the stator 332 is provided in the optical axis direction (that is, inside the stator 332). The radial ball bearing portion may be provided within a range in which at least a part thereof is provided with the rotor 331 in the optical axis direction (that is, inside the rotor 331).

When the radial ball bearing portion is provided on the image side of the cam ring 322 on the subject side end of the cam ring 322 on the radial side of the vibration type motor in this way, the bearing portion is provided on the subject side end portion of the cam ring. The length of the focus drive unit in the optical axis direction can be shortened as compared with the above. As a result, the interchangeable lens can be miniaturized.

A reflective film scale 335, which is formed in a band shape and has flexibility, is fixed (attached) to the inner peripheral surface of the scale ring 326. A reflection pattern for position detection is formed on the film scale 335. The film scale 335 constitutes an optical encoder together with the sensor head 336 described later.

The sensor head 336 shown in FIG. 4 has a light emitting unit that irradiates the film scale 335 with light and a light receiving unit that receives the reflected light from the reflection pattern of the film scale 335. The light receiving unit photoelectrically converts the received reflected light and outputs a detection signal. The sensor head 336 is fixed to the base ring 325 by adhesion or the like.

As shown in FIG. 4, guide rollers 338 are rotatably held and attached around the roller shaft 339 by the roller holder 345 at three locations in the circumferential direction on the outer peripheral portion of the base ring 325. The guide roller 338 comes into contact with the inner peripheral surface 326b of the scale ring 326 and holds it rotatably in the circumferential direction. Of the three guide rollers 338, one guide roller 338 provided on the side opposite to the sensor head 336 with the optical axis x interposed therebetween is spring-urged outward in the radial direction as described later. As a result, the scale ring 326 can be urged in the radial direction so that the distance between the sensor head 336 and the film scale 335 does not change.

A more detailed configuration and position detection principle of the optical encoder will be described with reference to FIGS. 7 to 10. In this embodiment, an absolute encoder capable of detecting an absolute position in the circumferential direction is used. FIG. 7A shows an encoder viewed from an angle, and FIG. 7B shows a cross section of the encoder. FIG. 8A shows a film scale (hereinafter, simply referred to as a scale) 335 seen from the sensor head side, and FIG. 8B shows a part of the scale 335 in an enlarged manner. In FIGS. 7 (a) and 7 (b) and 8 (a) and 8 (b), the scale 335 is described so as to extend in a plane, but it is actually along the inner peripheral surface of the scale ring 326. It is bent. Further, in FIGS. 7A and 7B, the Y-axis as the coordinate axis corresponds to the optical axis direction, the X-axis corresponds to the circumferential direction, and the Z direction corresponds to the radial direction.

As shown in FIGS. 7A and 7B, the scale 335 and the sensor head 336 are arranged so as to face each other. The scale 335 is movable in the X-axis direction with respect to the sensor head 336. The light emitting unit 336a is composed of an LED chip or the like. The two photochip ICs 336b and 336c, which are two light receiving elements, have built-in light receiving units 336d and 336e and a signal processing circuit, respectively. The photochip ICs 336b and 336c are mounted on the printed circuit board 336f and are covered with the transparent resin 336g together with the light emitting portion 336a. The upper surface (the surface on the scale side) of the transparent resin 336 g is covered with the protective glass 336h.

As shown in FIG. 8A, reflection patterns arranged at a predetermined period (pitch) are formed on the scale 335. The reflection pattern is formed by a reflection film. The scale 335 has a first track 335a and a second track 335b on which different reflection patterns are formed. The reflection pattern 335c of the first track 335a is formed at the pitch P1, and the reflection pattern 335d of the second track 335b is formed at a pitch P2 larger than the pitch P1. In the reflection pattern 335d, the reflection portion and the missing portion alternately repeat in the scale width direction (optical axis direction), and the width (that is, the reflection area) of the reflection portion in the scale longitudinal direction (circumferential direction) changes in the scale longitudinal direction. Has a configuration.

As shown in FIGS. 7A and 7B, the light emitted from the light emitting element 336a irradiates the scale 335. The light reflected by the first track 335a (reflection pattern 335c) of the scale 335 is received by the light receiving unit 336d. Further, the light reflected by the second track 335b (reflection pattern 335d) of the scale 335 is received by the light receiving unit 336e. The amount of light emitted by the light emitting element 336a is controlled according to the amount of light received by the light receiving unit 336c or 336d, and fluctuations in the amount of light received can be suppressed.

FIG. 9 shows an example of a detection signal output from the light receiving unit 336e that has received the reflected light from the second track 335b. The amplitude of the detection signal changes according to the change in the reflection area of the above-mentioned reflection pattern 335d in the longitudinal direction of the scale.

A plurality of light receiving elements are arranged in each of the light receiving unit 336d and the light receiving unit 336e in the longitudinal direction of the scale. The light receiving unit 336d is configured to generate two sinusoidal signals having a period corresponding to the pitch P1 and having a phase different from each other by 90 ° from the outputs of the plurality of light receiving elements. Further, the light receiving unit 336e is configured to generate two sinusoidal signals having a period corresponding to the pitch P2 and having a phase different from each other by 90 ° from the outputs of the plurality of light receiving elements.

10 (a) to 10 (c) show the principle of detecting the absolute position by the encoder configured as described above. FIG. 10 (c) shows a lower signal. This lower signal is a periodic signal that repeats the change of the signal value between -π and + π obtained by inversely tangent conversion of two sinusoidal signals generated by the light receiving unit 336d that are 90 degrees out of phase with each other. Is. Similarly, by performing inverse tangent conversion of two sinusoidal signals generated by the light receiving unit 336e that are 90 degrees out of phase with each other, a lower signal that repeats the change of the signal value between −π and + π can be obtained.

FIG. 10B shows a middle signal as a periodic signal obtained by subtracting the lower signal obtained from each of the light receiving unit 336d and the light receiving unit 336e. FIG. 10A is a high-order signal and is a signal corresponding to the amplitude shown in FIG.

The absolute position identifies the current middle signal from the signal value of the upper signal and the signal of which period, and further, from the signal value of the middle signal, the current lower signal is the period of which. It can be obtained by specifying whether it is.

In order to accurately detect the rotation position (rotation angle) of the scale ring 326 with respect to the base ring 325 by the encoder configured as described above, it is important that the distance between the scale 335 and the sensor head 336 does not fluctuate. be. Therefore, it is necessary to rotatably hold the scale ring 326 so that its rotation center axis is not displaced with respect to the base ring 325.

Of the three guide rollers 338 described above, two roller shafts 339 are fixed to the base ring 325. On the other hand, the holding structure of one guide roller (hereinafter referred to as an urging guide roller) 338 arranged on the opposite side of the sensor head 336 with respect to the optical axis x shown in FIG. 4 is shown in FIGS. 11 (a) and 11 (b). ).

The guide roller holder 345 holds the roller shaft 339 of the urging guide roller 338 in the two holes 345a and 345b. Two compression coil springs (third urging members) 346 are arranged between the guide roller holder 345 and the base ring 325. With this holding structure, the urging guide roller 338 is urged radially outward from the base ring 325 together with the guide roller holder 345. As a result, the inner peripheral surface 326b of the scale ring 326 comes into contact with the three guide rollers 338, and the scale ring 326 can rotate at a fixed position with respect to the base ring 325 without displacement of its rotation center axis.

Further, the thrust spring (second urging member) 355 attached to the end of the base ring 325 on the image side urges the scale ring 326 toward the subject to urge the end of the scale ring 326 on the subject side. It is pressed against the wall portion 325a of the base ring 325. As a result, the scale ring 326 is positioned with respect to the base ring 325 in the optical axis direction. A sliding ring 325b for reducing the rotational resistance of the scale ring 326 is arranged between the end of the scale ring 326 on the subject side and the wall portion 325a of the base ring 325. With this configuration, the scale ring 326 can rotate at a fixed position in the optical axis direction with respect to the base ring 325.

As described above, the scale ring 326 is positioned in the radial direction with respect to the base ring 325 by the urging force of the compression coil spring 346, and is further positioned in the optical axis direction by the urging force of the thrust spring 355. Therefore, the positional relationship between the scale 335 and the sensor head 336 can be maintained with high accuracy, and the accuracy of detecting the rotation position by the encoder can be improved. Further, the scale ring 326 is freed from play in the circumferential direction with respect to the connecting ring (connecting member) 330, that is, the cam ring 322 by the urging force of the leaf spring 354. As a result, the error between the detection result of the rotation position by the encoder and the actual rotation position of the cam ring 322 can be reduced, and as a result, the position of the focus lens unit driven by the cam ring 322 in the optical axis direction can be reduced. The detection accuracy can be improved.

The magnitude of the urging force of each of the leaf spring 354, the compression coil spring 346, and the thrust spring 355 is set so that the scale ring 326 is not twisted by these urging forces.

Specifically, the thrust spring 355 generates an urging force that urges the scale ring 326 in the optical axis direction. At this time, a holding force for holding the scale ring 326 in the radial direction orthogonal to the optical axis is generated by the frictional force between the thrust spring 355 and the contact portion of the scale ring 326. The urging force of the compression coil spring 346 is set to a urging force larger than the holding force. This is because if the urging force of the compression coil spring 346 is smaller than the holding force, the scale ring 326 cannot be properly brought into contact with the guide roller 338, and the scale ring 326 is tilted with respect to the base ring 325. This is because there is a possibility that the displacement of the.

Further, in this embodiment, since it is sufficient that the scale ring 326 itself can be held so as to rotate at a fixed position, the urging forces of the leaf spring 354, the compression coil spring 346, and the thrust spring 355 can be set small. This is because the scale ring 326 is connected to the interlocking ring 330 and rotates almost integrally with the scale ring 326, so that the scale ring 326 is not subjected to the load as when driving the cam ring 322 via the scale ring 326. Is. Therefore, it is possible to suppress wear in the focus drive unit and an increase in the drive load due to the urging force. As a result, it is possible to realize an interchangeable lens having high durability performance capable of detecting the position of the focus lens unit with high detection accuracy.

In this embodiment, the case where the rotation of the vibrating motor is transmitted to the cam ring 322 via the interlocking ring 330, which is a separate member, has been described. However, the rotation of the vibrating motor is directly transmitted to the cam ring. You may. That is, it is not necessary to provide the interlocking ring 330.

Further, in this embodiment, the case where the play in the circumferential direction between the scale ring 326 and the connecting ring 330 is removed by using the leaf spring 354 has been described, but the scale ring 326 and the connecting ring are connected by an adhesive having an elastic force. It may be integrated with 330.

Further, in this embodiment, a radial ball bearing structure is used in which the ball 350 is in contact with the ball 350 on a contact surface (ball race surface) inclined with respect to the optical axis direction, but the contact surface with the ball provided on the cam ring is illuminated. It may be a plane orthogonal to the axis. Even with this structure, it is possible to receive the urging force of the pressure spring and suppress the backlash in the optical axis direction between the cam ring and the guide cylinder. In this case, by fitting the outer peripheral surface of the guide cylinder and the inner peripheral surface of the cam ring so as not to cause resistance to the rotation of the cam ring, it is possible to suppress the backlash of the cam ring with respect to the guide cylinder in the radial direction.

Further, in this embodiment, a case where the scale 335 is held by the rotatable scale ring (holding ring) 326 and the sensor head 336 is held by the base ring (fixed ring) 325 has been described. However, the sensor may be held by a rotatable holding ring and the scale may be held by a fixed ring.

Further, in this embodiment, the interchangeable lens used in the interchangeable lens camera system has been described, but the same configuration as in this embodiment may be applied to the lens barrel of a lens-integrated camera (still camera or video camera). ..

Each of the above-described examples is only a representative example, and various modifications and changes can be made to each of the examples in carrying out the present invention.

101 Interchangeable Lens 103 Focus Lens 321 Guide Cylinder 322 Cam Ring 326 Scale Ring 325 Base Ring 326a Key Part 330 Interlocking Ring 330a Recess 331 Rotor 332 Stator 335 Film Scale 336 Sensor Head 346 Compression Coil Spring 354 Leaf Spring 355 Thrust Spring

Claims (4)

A lens unit that can move in the optical axis direction and
A drive source that generates a rotational force in the direction around the optical axis,
A drive ring that rotates in the direction around the optical axis to move the lens unit in the direction of the optical axis.
An encoder provided to detect the rotational position of the drive ring and
It has a fixed ring that holds one of the scale and the sensor that make up the encoder, and a transmitted part that transmits rotation from the transmitting part that rotates in the direction around the optical axis, and holds the other of the scale and the sensor. And the holding ring that can rotate in the direction around the optical axis,
A first urging member that urges the holding ring to one side in the direction around the optical axis so as to press the transmitted portion against the transmitted portion in the direction around the optical axis.
A second urging member that urges the holding ring to one side in the optical axis direction in order to position the holding ring with respect to the fixed ring in the optical axis direction.
A third attachment that urges the holding ring to one side in the radial direction with respect to the fixed ring in order to position the holding ring with respect to the fixed ring in a radial direction orthogonal to the optical axis direction. Has a force member and
The drive ring receives the rotational force directly from the drive source or via a connecting member fixed to the drive ring.
The lens device is characterized in that the transmission unit is provided on the drive ring or the connecting member. The drive source is
A vibrating body whose vibration is excited by electrical-mechanical energy conversion,
The lens device according to claim 1, further comprising a rotating body that can rotate integrally with the driving ring or the connecting member and is rotationally driven by contacting the vibrating body. The lens device according to claim 1 or 2, wherein the drive ring has a cam that moves the lens unit in the optical axis direction. The lens device according to any one of claims 1 to 3.
An image pickup device including an image pickup element that photoelectrically converts light that has passed through the lens unit.

Images