Patent Publication Number: US-2023142396-A1

Title: Optical apparatus

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an optical apparatus that moves a plurality of lens units for zooming, focusing, etc. 
     Description of the Related Art 
     In order to reduce the shortest imaging distance and to improve the image quality in close-up imaging, a plurality of lens units may be moved during focusing. Japanese Patent Laid-Open No. (“JP”) 2005-284144 discloses an optical apparatus that arranges a plurality of drivers (actuators) for moving a plurality of lens units, respectively, on a straight line parallel to an optical axis. PCT International Publication No. (“WO”) 16/051617 discloses an optical apparatus that arranges a plurality of actuators for moving a plurality of lens units, respectively, on the same circle centered at the optical axis in a plane orthogonal to the optical axis. 
     It is necessary to widely space the plurality of actuators aligned in the optical axis direction as in JP 2005-284144 if the lens units are widely spread in the optical axis direction. Then, a compact structure of the optical apparatus is hindered. In addition, when a plurality of actuators are aligned in the circumferential direction as in WO 16/051617 and another fixed lens unit is disposed among the lens units that are driven by these actuators, it becomes difficult to secure a phase area for holding the fixed unit. 
     SUMMARY OF THE INVENTION 
     The present invention provides a compact optical apparatus having a plurality of actuators (drivers) for driving a plurality of lens units. 
     An optical apparatus according to one aspect of the present invention includes a plurality of optical elements arranged in an optical axis direction, a first holding member and a second holding member configured to hold a first optical element and a second optical element, respectively, among the plurality of optical elements, a first guide member and a second guide member configured to guide movements of the first holding member and the second holding member, respectively, in the optical axis direction, a first driver and a second driver configured to drive the first holding member and the second holding member, respectively, in the optical axis direction, a base member configured to hold the first driver and second driver, and holders configured to cause the base member to hold a third holding member that holds a third optical element among the plurality of optical elements, or configured to cause another member to hold the base member, and provided at three locations in a circumferential direction around an optical axis when the optical apparatus is viewed from the optical axis direction. Where a first axis, a second axis, and a third axis are defined as axes passing through the optical axis and the holders at the three locations, the first driver and the first guide member are disposed in a first area between the first axis and the second axis, and the second driver and the second guide member are disposed in a second area between the first axis and the third axis. The first driver and second driver are disposed in two areas that at least partially overlap each other in the optical axis direction. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a sectional view of an interchangeable lens according to a first embodiment when it is viewed from an optical axis direction. 
         FIG.  2    is a sectional view of the interchangeable lens according to the first embodiment at a wide-angle end. 
         FIG.  3    is a sectional view of the interchangeable lens according to the first embodiment at a telephoto end. 
         FIG.  4    is an exploded perspective view of the interchangeable lens according to the first embodiment. 
         FIG.  5    illustrates the interchangeable lens according to the first embodiment when it is viewed from the direction of a first axis. 
         FIG.  6    is a sectional view of an interchangeable lens according to a second embodiment when it is viewed from the optical axis direction. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Referring now to the accompanying drawings, a description will be given of embodiments according to the present invention. 
     First Embodiment 
       FIGS.  2  and  3    illustrate a configuration of an interchangeable lens  100  as an optical apparatus (lens apparatus) according to a first embodiment of the present invention.  FIG.  2    illustrates a section when the interchangeable lens  100  at the wide-angle end is cut parallel to an optical axis, and  FIG.  3    illustrates a section when the interchangeable lens  100  at the telephoto end is cut parallel to the optical axis. The interchangeable lens  100  is attached to and a detachable from a camera body as an image pickup apparatus (not shown) including an image sensor such as a CCD sensor or a CMOS sensor. 
     The interchangeable lens  100  has an imaging optical system including first to seventh lens units L 1  to L 7  arranged in order from an object side (front side). The imaging optical system forms light from an unillustrated object to form an object image on an image sensor in a camera body. Focusing is performed by moving a floating lens unit as the fourth lens unit L 4  and a focus lens unit as the sixth lens unit L 6  in the optical axis direction, and zooming (magnification variation) is performed by moving the first to seventh lens units L 1  to L 7  in the optical axis direction. While the interchangeable lens is described in this embodiment, the optical apparatus may be a lens integrated image pickup apparatus. 
     A lens mount  111  has a bayonet part used to detachably attaching the interchangeable lens to the camera body, and is fixed onto a rear fixed barrel  112  with a screw via an exterior barrel  113 . The exterior barrel  113  is sandwiched and fixed between the lens mount  111  and the rear fixed barrel  112 . A front fixed barrel  115  is fixed onto the rear fixed barrel  112  with screws. A zoom index and operation switches (not shown) are attached to the front fixed barrel  115 . A guide barrel  116  is fixed onto the rear fixed barrel  112  with screws. 
     The guide barrel  116  is formed with a linear groove for guiding each lens unit in the optical axis direction. The guide barrel  116  is provided with a cam groove portion, and a cam follower (not shown) screwed onto a cam barrel  117  is engaged with the cam groove portion. Thereby, the cam barrel  117  (linearly) moves in the optical axis direction while rotating around the optical axis during zooming. The cam barrel  117  is formed with a plurality of cam groove portions that linearly move the respective lens units that move during zooming. 
     A zoom operation barrel  118  is radially fitted to and bayonetted with the guide barrel  116  and rotatably held around the optical axis. The rotation of the zoom operation barrel  118  caused by the zoom operation by the user makes a rectilinear barrel  122  linearly move due to a rectilinear guiding function of the cam groove portion formed in the zoom operation barrel  118 , the cam follower provided outside of the rectilinear barrel  122 , and a rectilinear groove portion in the guide barrel  116 . The cam follower of the rectilinear barrel  122  is also engaged with the cam groove portion in the cam barrel  117 , so that as the rectilinear barrel  122  linearly moves, the cam barrel  117  rotates around the optical axis. At this time, the cam barrel  117  that is rotatable and linearly movable relative to the guide barrel  116  linearly moves while rotating due to the linear movement of the rectilinear barrel  122 . 
     When the cam barrel  117  rotates and linearly moves relative to the guide barrel  116 , the rear unit and the seventh unit are separately driven in the optical axis direction, because rear rollers  123  provided at three circumferential positions around the optical axis of the rear unit described later and the seventh unit roller  124  provided at three circumferential positions of the seventh unit described later are engaged with the rectilinear groove portions in the guide barrel  116  and the cam groove portions in the cam barrel  117 . 
     Thus, in the interchangeable lens  100  according to this embodiment, the rectilinear barrel  122  linearly moves (and the first lens unit L 1  fixed to the rectilinear barrel  122  moves in the optical axis direction as described later) when the zoom operation barrel  118  is rotated, and the second to seventh lens units L 2  to L 7  are moved in the optical axis direction when the cam barrel  117  is rotated and linearly moved. 
     The first lens holding frame  101  holds the first lens unit L 1  and is fixed onto the rectilinear barrel  122  with screws. A first lens pressing ring  125  has a female screw formed on its inner peripheral portion and is screwed with a male screw formed on the outer peripheral portion of the rectilinear barrel  122 . The first lens pressing ring  125  serves to fix the first lens unit L 1 . 
     A bayonet claw for attaching a hood is formed on the outer circumferential part of the rectilinear barrel  122 , and a screw for attaching accessories such as a filter is formed on the inner circumferential part. 
     The second lens holding frame  102  holds the second lens unit L 2  and constitutes part of an image stabilizing unit  108 . The image stabilizing unit  108  holds the second lens holding frame  102  so that the second lens holding frame  102  is movable in a direction orthogonal to the optical axis (referred to as a shift direction hereinafter), and its shift actuator including a magnet and a coil drives the second lens holding frame  102  in the shift direction so as to reduce the image blurs. The image stabilizing unit  108  is held while suspended from the guide barrel  116  via rollers. 
     The third lens holding frame  103  holds the third lens unit L 3 , and is held by the rear unit base  126  via three cam followers ( 129  in  FIG.  5   ) located at three circumferential positions of the third lens holding frame  103 . The third lens holding frame  103  moves in the optical axis direction by the rear unit base  126  that linearly moves during zooming. The third lens holding frame  103  holds an electromagnetic diaphragm unit  110  including a plurality of diaphragm blades and a diaphragm actuator that opens and closes the diaphragm blades. 
     The fourth lens holding frame  104  serving as the first holding member holds the fourth lens unit L 4  serving as the first optical element, and is linearly guided by a guide bar  153  serving as a first guide member whose front end and rear end are held by the rear unit base  126  and the first rear cover  127  fixed to the rear unit base  126 . The fourth lens unit L 4  (fourth lens holding frame  104 ) is moved in the same direction as that of the rear unit base  126  when the rear unit base  126  is moved in the optical axis direction during zooming, and is moved relative to the rear unit base  126  in the optical axis direction by the fourth lens driving motor unit  151  that serves as a first driver. 
     The fourth lens holding frame  104  has a scale for detecting the position in the optical axis direction. An optical sensor facing the scale is fixed to the rear unit base  126  via a flexible printed circuit board (FPC). The scale and the optical sensor constitute a position detector. 
     The fifth lens holding frame  105  serving as the third holding member holds the fifth lens unit L 5  serving as the third optical element, and is held by the rear unit base  126  via three cam followers (holders)  159  fixed at three circumferential positions of the fifth lens holding frame  105 . The fifth lens holding frame  105  is moved in the optical axis direction by the rear unit base  126  when the rear unit base  126  is linearly moved during zooming. 
     The sixth lens holding frame  106  as the second holding member holds the sixth lens unit L 6  as the second optical element, and is linearly guided by the guide bar  155  as the second guide member whose front end and the rear end are held by the rear unit base  126  and the first rear unit cover  127 . 
     The motor unit driving base  135  is attached to the rear unit base  126  movably in the optical axis direction, and is bayonetted with the seventh unit base  109  integrally only in the optical axis direction. The biasing force of the seventh unit spring  136  attached to the seventh unit base  109  removes play (looseness) in the optical axis direction between the seventh unit base  109  and the motor unit driving base  135 . 
     The sixth lens holding frame  106  is driven in the optical axis direction relative to the motor unit driving base  135  by the sixth lens driving motor unit  152  as the second driver. 
     The seventh lens holding frame  107  holds the seventh lens unit L 7  and is screwed with the seventh unit base  109 . During zooming, the seventh lens holding frame  107  is driven in the optical axis direction together with the seventh unit base  109  by three cam followers provided on the seventh unit base  109 . The seventh unit base  109  and the seventh lens holding frame  107  form a seventh unit. 
     This embodiment uses a vibration type linear motor using a piezoelectric element for the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152 . The vibration type linear motor includes a motor stator  130 , a motor mover  131  that is excited by a piezoelectric element to move in the optical axis direction relative to the motor stator  130 , and a motor output part that moves in the optical axis direction together with the motor mover  131 . The motor stators  130  of the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152  are fixed to the motor unit driving base  135 . The motor unit driving base  135 , together with the rear unit base  126 , constitutes a base member that holds the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152 . 
     An arm  132 , which is a driving transmission member that transmits the driving forces from the motor output parts to the fourth lens holding frame  104  or the sixth lens holding frame  106 , is engaged with each of the motor output parts of the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152 , as illustrated in  FIG.  1    and  FIG.  4    that is an exploded view of the rear unit. Thereby, the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152  can drive the fourth lens holding member  104  and the sixth lens holding member  106  in the optical axis direction. However,  FIGS.  1  and  4    illustrate only the arm  132  provided to the sixth lens holding frame  106 . 
     A stepping motor may be used for each of the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152 , and the arm may be engaged with the lead screw provided to the motor output part. When the stepping motor is used, the position detector may be omitted to perform an open driving control. 
     The zoom operation barrel  118  is provided with a groove portion that holds a mover of a resistance type linear sensor (potentiometer)  134  that is an unillustrated zoom position detector fixed to the guide barrel  116 . The zoom position can be detected by changing the output of the resistance type linear sensor  134  according to a rotating amount of the zoom operation barrel  118 . 
     The focus operation barrel  114  is sandwiched between the front fixed barrel  115  and the rear fixed barrel  112  so that it can rotate at a fixed position in the optical axis direction on the outer circumference of the front fixed barrel  115 . The rotation amount and direction of the focus operation barrel  114  are detected by a photodetector provided to the front fixed barrel  115  and a striped scale provided to the inner circumferential part of the focus operation barrel  114  so as to face the photodetector. 
     A multipurpose operation barrel  121  is sandwiched between the rear fixed barrel  112  and the exterior barrel  113  so that it can rotate at a fixed position in the optical axis direction on the outer circumference of the rear fixed barrel  112 . The rotation amount and direction of the multipurpose operation barrel  121  are detected by a photodetector provided to the rear fixed barrel  112  and a striped scale provided to the inner circumferential part of the multipurpose operation barrel  121  opposite to the photodetector. In addition, the multipurpose operation barrel  121  and the rear fixed barrel  112  have a click mechanism including a plurality of groove portions for giving a click sense to a user operation and a click pin biased by a spring in the groove portions. 
     A lens controller (control board)  119  serving as a controller controls the entire operation of the interchangeable lens  100 , such as a focus driving control, a diaphragm driving control, and an image stabilization control. During zooming, the lens controller  119  controls moving of the fourth lens unit L 4  and the sixth lens unit L 6  (or driving of the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152 ) so as to keep below certain values the focus position and the amount of various aberrational amounts that fluctuate due to zooming. The lens controller  119  is fixed to the rear fixed barrel  112  with screws. 
     Referring now to  FIGS.  1 ,  4  and  5   , a description will be given of a more detailed configuration of the rear unit.  FIG.  1    illustrates the rear unit viewed from the optical axis direction (front side).  FIG.  4    illustrates the rear unit exploded as described above.  FIG.  5    illustrates the rear unit viewed from the direction of a first axis which will be described later. 
     The third to sixth lens units L 3  to L 6  are held on the rear unit base  126  that linearly moves during zooming. However,  FIG.  4    illustrates only the fourth to sixth lens units L 4  to L 6 . 
     As described above, the fourth lens unit L 4  held by the fourth lens holding frame  104  is a floating unit, and driven in the optical axis direction by the fourth lens driving motor unit  151 . A sleeve portion  104   a  of the fourth lens holding frame  104  is engaged with (fitted to) the guide bar  153  movably in the optical axis direction at two positions before and after the sleeve portion  104   a , and thereby the position of the fourth lens holding frame  104  is determined in a direction orthogonal to the optical axis and the fourth lens holding frame  104  is prevented from tilting relative to the optical axis. A U-groove portion  104   b  in the fourth lens holding frame  104  is engaged with a rotation stopping bar  154  as a first rotation stopping member movably in the optical axis direction. The front end of the rotation stopping bar  154  is held by the rear unit base  126 , and its rear end is held by the second rear unit cover  128  fixed to the rear unit base  126 . 
     The arm  132  rotatably attached to the fourth lens holding frame  104  is biased by a biasing force of a torsion spring (biasing unit)  133  disposed around its rotational center axis and engaged with the motor output part of the fourth lens driving motor unit  151 . Thereby, the loose engagement of the arm  132  with the motor output part is removed. The biasing force of the torsion spring  133  biases the fourth lens holding frame  104  in a direction to rotate the fourth lens holding frame  104  around the guide bar  153 , and brings the groove  104   b  into contact with the rotation stopping bar  154 . Thereby, the rotational play of the fourth lens holding frame  104  is removed. 
     The position of the fourth lens holding frame  104  in the optical axis direction relative to the rear unit base  126  is detected by reading an unillustrated scale fixed to the fourth lens holding frame  104  through the fourth lens position sensor  157  as a first position detector fixed to the rear unit base  126 . 
     As described above, the fifth lens holding frame  105  is held by the rear unit base  126  via the three cam followers  159  fixed to follower attachment portions  105   a  provided at three positions in the circumferential direction. 
     As described above, the sixth lens unit L 6  held by the sixth lens holding frame  106  is the focus unit, and driven in the optical axis direction by the sixth lens driving motor unit  152 . A sleeve portion  106   a  of the sixth lens holding frame  106  is engaged with (fitted to) the guide bar  155  movably in the optical axis direction at two positions before and after the sleeve portion  106   a , and thereby the position of the sixth lens holding frame  106  is determined in a direction orthogonal to the optical axis and the sixth lens holding frame  106  is prevented from tilting relative to the optical axis. AU-groove portion  106   b  in the sixth lens holding frame  106  is engaged with the rotation stopping bar  156  as the second rotation stopping member movably in the optical axis direction. The front end of the rotation stopping bar  156  is held by the rear unit base  126 , and its rear end is held by the second rear unit cover  128 . 
     The arm  132  rotatably attached to the sixth lens holding frame  106  is biased by the biasing force of the torsion spring  133  disposed around the rotational center axis and engaged with the motor output part of the sixth lens driving motor unit  152 . Thereby, the loose engagement of the arm  132  with the motor output part is removed. The biasing force of the torsion spring  133  biases the sixth lens holding frame  106  in a direction to rotate the sixth lens holding frame  106  around the guide bar  155 , and brings the U-groove portion  106   b  into contact with the rotation stopping bar  156 . Thereby, the rotational play (looseness) of the sixth lens holding frame  106  is removed. 
     The position of the sixth lens holding frame  106  in the optical axis direction relative to the rear unit base  126  is determined by the position of the motor unit driving base  135  relative to the rear unit base  126  and the position of the motor mover  131  of the sixth lens driving motor unit  152  relative to the motor unit driving base  135  in the optical axis direction. The position of the sixth lens holding frame  106  relative to the rear unit base  126  in the optical axis direction is detected by reading an unillustrated scale fixed to the sixth lens holding frame  106  through a sixth lens position sensor  158  as a second position detector fixed to the rear unit base  126 . 
     In the description of this embodiment, the fourth lens unit L 4  is the floating unit and the sixth lens unit L 6  is the focus unit, and these lens units are moved during focusing, but one of these lens units may be moved during zooming and the other lens unit may be moved during focusing. In the description of this embodiment, the sixth lens unit L 6  is moved relative to the motor unit driving base  135 , but the motor unit driving base  135  may be omitted. 
     Referring now to  FIG.  1   , a description will be given of an arrangement of the components in the rear unit. A first axis A 1 , a second axis A 2 , and a third axis A 3  illustrated in  FIG.  1    pass through a position of an optical axis AX, and are straight lines that pass through the center of three cam followers  159  that cause the rear unit base  126  to hold the fifth lens holding frame  105 . The three cam followers  159  are arranged at intervals of approximately 120 degrees in the circumferential direction. Thus, the angles formed by the adjacent axes in the circumferential direction among the first to third axes A 1 , A 2  and A 3  are also approximately 120 degrees. 
     In this embodiment, since the three cam followers  159  that cause the rear lens unit base  126  to hold the fifth lens holding frame  105  and the three rear unit rollers (holders)  123  that cause the guide barrel (other member)  116  to hold the rear lens unit base  126  (or the rear lens unit) are arranged at the same phases, the first axis A 1 , the second axis A 2 , and the third axis A 3  when viewed from the optical axis direction are straight lines that pass through the optical axis AX and pass through the centers of the three rear unit rollers  123 . 
     In the circumferential direction, an area sandwiched between the first and second axes A 1  and A 2  will be set to a first area AR 1 , and an area sandwiched between the first and third axes A 1  and A 3  will be set to a second area AR 2 . An area sandwiched by the second and third axes A 2  and A 3  will be set to a third area AR 3 . 
     Arranged in the first area AR 1  are the fourth lens driving motor unit  151 , the arm  132  provided to the fourth lens holding frame  104 , the torsion spring  133  for biasing the arm  132 , and the guide bar  153  for guiding the fourth lens holding frame  104 . The guide bar  153  is disposed at a position distant from the first axis A 1  than the fourth lens driving motor unit  151 . Arranged in the first area AR 1  are a rotation stopping bar  156  that stops rotating the sixth lens holding frame  106  near the guide bar  153  (or farther from the first axis A 1  than the fourth lens driving motor unit  151 ). 
     Arranged in the second area AR 2  are the sixth lens driving motor unit  152 , a latch  132  provided to the sixth lens holding frame  106 , the torsion spring  133  for biasing the same, and the guide bar  155  for guiding the sixth lens holding frame  106 . The guide bar  155  is disposed at a position distant from the first axis A 1  than the sixth lens driving motor unit  152 . Arranged in the second area AR 2  is the rotation stopping bar  154  that stops rotating the fourth lens holding frame  104  near the guide bar  155  (or farther from the first axis A 1  than the sixth lens driving motor unit  152 ). 
     In this embodiment, the fourth and sixth lens units L 4  and L 6  driven by the fourth and sixth lens driving motor units  151  and  152  respectively sandwich the fifth lens unit L 5  therebetween but are close to each other in the optical axis direction. As described above, such a lens unit arrangement arranges the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152  in the first area AR 1  and the second area AR 2 , respectively, which are areas different from each other in the circumferential direction and thereby can arrange, as illustrated in  FIGS.  1  and  5   , the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152  in two areas that at least partially overlap each other in the optical axis direction. Thereby, the rear unit (or finally the interchangeable lens  100 ) can be made smaller in the optical axis direction than that where the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152  are arranged in two areas that do not overlap each other at all in the optical axis direction. 
     By disposing the lens driving motor unit and relevant components (the arm  132 , the torsion spring  133 , and the guide bars  153  and  155 ) in each of the first area AR 1  and the second area AR 2 , the follower attachment portion  105   a , to which the cam follower  159  for holding the fifth lens holding frame  105  is attached, can be disposed near the boundary of each area, and the follower attachment portion  105   a  can be secured without increasing the size of the interchangeable lens  100 . 
     As described above, this embodiment can make compact the interchangeable lens  100  having the fourth and sixth lens driving motor units  151  and  152  for driving the fourth and sixth lens units L 4  and L 6 . 
     In this embodiment, the fourth lens driving motor unit  151  and relevant components, and the sixth lens driving motor unit  152  and relevant components are arranged in line symmetry with respect to the first axis A 1 . The term “arranged in line symmetry,” as used herein, includes both an arrangement in perfect line symmetry and an arrangement that can be considered to be in substantially line symmetry.  FIG.  1    illustrates a moment M 1  generated in the fourth lens holding frame  104  by the biasing force of the torsion spring  133  for biasing the arm  132  provided to the fourth lens holding frame  104  and a moment M 2  generated in the sixth lens holding frame  106  by the biasing force of the torsion spring  133  for biasing the arm  132  provided to the sixth lens holding frame  106 .  FIG.  1    also illustrates a reaction force F 1  received by the U-groove portion  104   b  of the fourth lens holding frame  104  by the moment M 1  and a reaction force F 2  received by the U-groove portion  106   b  of the sixth lens holding frame  106  by the moment M 2 . 
     A direction of the reaction force F 1  is a direction orthogonal to a straight line that connects the guide bar  153  and the U-groove portion  104   b  in the fourth lens holding frame  104 , and a direction of the reaction force F 2  is a direction orthogonal to a straight line that connects the guide bar  155  and the U-groove portion  106   b  in the sixth lens holding frame  106 . Therefore, the reaction forces F 1  and F 2  can work in the same direction when the arm  132 , the torsion spring  133 , and the U-groove portions  104   b  and  106   b  relevant to the fourth and sixth lens holding frames  104  and  106  are arranged in line symmetry with respect to the first axis A 1 . The same direction, as used herein, is not limited to completely the same (parallel) direction, but may be a nonparallel direction that can be regarded as substantially the same direction. 
     If the biasing force of the torsion spring  133  is smaller than the own weight of the lens unit and the lens holding frame, there will be the play in holding the lens holding frame, but the reaction forces F 1  and F 2  working in the same direction eliminate the need to generate a strong biasing force only in one torsion spring  133 . It is thus unnecessary to use a large spring or to thicken a guide bar in order to secure the strength against the large load generated by a strong biasing force, and the interchangeable lens  100  can be made compact. In addition, it is possible to avoid a large frictional force between the guide bar and the lens holding frame (sleeve portion and U-groove portion) due to the large load, and it is unnecessary to increase the driving force of the lens driving motor unit or the size of the lens driving motor unit. Therefore, the interchangeable lens  100  can save power and can be made compact. 
     In order to match the directions of the reaction forces F 1  and F 2 , the guide bar  153  for the fourth lens holding frame  104  and the rotation stopping bar  156  for the sixth lens holding frame  106  may be brought close to each other, and the guide bar  155  for the sixth lens holding frame  106  and the rotation stopping bar  154  for the fourth lens holding frame  104  may be brought close to each other. Moreover, one guide bar may be shared as the guide bar  153  for the fourth lens holding frame  104  and the rotation stopping bar  156  for the sixth lens holding frame  106 , and the other one guide bar may be shared as the guide bar  155  for the sixth lens holding frame  106  and the rotation stopping bar  154  for the fourth lens holding frame  104 . 
     This embodiment disposes the flexible printed circuit board  160  as the first connecting member that connects the fourth and sixth lens driving motor units  151  and  152  to the lens controller  119  so as to extend in the optical axis direction near the first axis A 1 . More specifically, as illustrated in  FIGS.  1  and  5   , the connector  151   b  of the fourth lens driving motor unit  151  and the connector  152   b  of the sixth lens driving motor unit  152  extend toward the flexible printed circuit board  160  disposed on the first axis A 1  side in their circumferential directions and are connected to the flexible printed circuit board  160 . 
     In order to enable such connections, this embodiment uses motor units having the same structure for the fourth lens driving motor unit  151  and the sixth lens driving motor unit  152 , and arranges them back to front. This eliminates the need to use separate motor units for the fourth and sixth lens driving motor units  151  and  152 . Since the fourth and sixth lens driving motor units  151  and  152  and the lens controller  119  can be connected by the single flexible printed circuit board  160 , the connecting space can be saved and the interchangeable lens  100  can be made compact. 
     This embodiment disposes the flexible printed circuit board  161  as the second connecting member that connects the fourth lens position sensor  157  and the sixth lens position sensor  158  to the lens controller  119 , in the third area AR 3  that is a phase area opposite to the first axis A 1  in  FIG.  1   . Since the third area AR 3  has a space wider than the first and second areas AR 1  and AR 2  in which the fourth and sixth lens driving motor units  151  and  152  and the like are arranged, the flexible printed circuit board  161  can be disposed in the third area AR 3  different from the first and second areas AR 1  and AR 2  and thus a reasonable arrangement can be realized. Moreover, since the fourth and sixth lens position sensors  157  and  158  can be connected to each other through the single flexible printed circuit board  161 , the connecting space can be reduced and the interchangeable lens  100  can be made compact. 
     The first to third axes A 1 , A 2 , and A 3  do not have to be straight lines passing through the centers of the three cam followers  159  in order to hold the fifth lens unit L 5 . For example, this embodiment arranges the three cam followers  159  and the three rear unit rollers  123  in the same phases, but may arrange the three rear unit rollers  123  in phases different from those of the three cam followers  159  and set the axes passing through the centers of the rollers  123  to the first to third axes. Instead of holding by the cam follower, holding by using a fixing member such as a screw may be used. 
     One modification of the above embodiment may allow the connectors  151   b  and  152   b  of the fourth and sixth lens driving motor units  151  and  152  to extend in the circumferential direction to the side opposite to the first axis A 1  side. In this case, the connector  151   b  of the fourth lens driving motor unit  151  and the fourth lens position sensor  157  are connected to the flexible printed circuit board, and this is connected to the lens controller  119 . Alternatively, the connector  152   b  of the sixth lens driving motor unit  152  and the sixth lens position sensor  158  are connected to another flexible printed circuit board, which is connected to the lens controller  119 . However, the connection in the above embodiment is suitable when the influence of noises generated by driving the fourth and sixth lens driving motor units  151  and  152  on the signals from the fourth and sixth lens position sensors  157  and  158 . 
     Second Embodiment 
       FIG.  6    illustrates a section viewed from the optical axis direction of an interchangeable lens according to a second embodiment of the present invention. Those elements in the interchangeable lens according to this embodiment, which are corresponding elements in the first embodiment, will be designated by reference numerals of the 200s with the last two digits of the reference numeral 100s of the first embodiment are the same. A first axis A 21 , a second axis A 22 , and a third axis A 23  illustrated in  FIG.  6    pass through the optical axis AX, and are straight lines that pass through the centers of the three cam followers  259  that cause the rear base  226  to hold the fifth lens unit, which is disposed between the fourth and sixth lens units. The three cam followers  259  are arranged at intervals of approximately 120 degrees in the circumferential direction. Therefore, the angles formed by the adjacent axes in the circumferential direction among the first to third axes A 21 , A 22  and A 23  are also approximately 120 degrees. In the circumferential direction, an area sandwiched between the first and second axes A 21  and A 22  will be set to a first area AR 21 , and an area sandwiched between the first and third axes A 21  and A 23  will be set to a second area AR 22 . An area sandwiched by the second and third axes A 22  and A 23  will be set to a third area AR 23 . 
     In this embodiment, the arrangement relationship between the fourth and sixth lens driving motor units and the guide bar is opposite to that of the first embodiment. More specifically, in the first embodiment, the guide bars  153  and  155  are located at positions farther from the first axis A 1  than the fourth and sixth lens driving motor units  151  and  152  in the first and second areas AR 1  and AR 2 , respectively. On the other hand, in this embodiment, the fourth and sixth lens driving motor units  251  and  252  are located in the first and second areas AR 21  and AR 22 , and the guide bars  253  and  255  are located at positions closer to the first axis A 21  than the sixth lens driving motor units  251  and  252  in the fourth and sixth areas AR 21  and AR 22 . The fourth lens position sensor  257  and the sixth lens position sensor  258  are also located near the first axis A 21  in accordance with the arrangement of the guide bars  253  and  255 . 
     The front ends of the guide bars  253  and  254  that guide the fourth lens holding frame  204  are held by the rear unit base  226 , and their rear ends are held by an unillustrated rear unit cover fixed to the rear unit base  226 . The sleeve portion  204   a  of the fourth lens holding frame  204  is engaged with the guide bar  253 , and the U-groove portion  204   b  is engaged with the rotation stopping bar  254  disposed in the third area AR 23 . 
     On the other hand, the front end of the guide bar  255  that guides the sixth lens holding frame  206  is held by the rear unit base  226 , and its rear end is held by the rear unit cover. The sleeve portion  206   a  of the sixth lens holding frame  206  is engaged with the guide bar  255 , and the U-groove portion  206   b  is engaged with the rotation stopping bar  254 , similar to the U-groove portion  204   b  of the fourth lens holding frame  204 . In other words, this embodiment uses the rotation stopping bar  254 , which is the same member (single unit), for the first rotation stopping member and the second rotation stopping member. 
     Similar to the first embodiment, an arm that is engaged with the motor mover of the fourth lens driving motor unit  251  and a torsion spring that biases this arm are disposed in the first area AR 21 . An arm that is engaged with the motor mover of the sixth lens driving motor unit  252  and a torsion spring that biases the arm are disposed in the second area AR 22 . 
     By thus disposing the lens driving motor unit and relevant components (arm, torsion spring, and guide bar  253  and  255 ) in the first area AR 21  and the second area AR 22 , respectively, the follower attachment portion “a” to which the cam follower  259  for holding the lens holding frame  205  is attached can be disposed near the boundary between the areas, and the follower attachment portion can be secured without increasing the size of the interchangeable lens. 
     Even in this embodiment, the interchangeable lens having the fourth and sixth lens driving motor units  251  and  252  for driving the fourth and sixth lens units can be made compact. 
     This embodiment may dispose near the first axis A 21 , the flexible printed circuit board  261  that connects the fourth lens position sensor  257 , the sixth lens position sensor  258 , and the unillustrated lens controller. This embodiment may dispose the flexible printed circuit board  260  that connects the fourth and sixth drive motor units  251  and  252  to the lens controller, in the third area AR 23 , which is the phase area on the opposite side of the first axis A 21 . This allows a space-saving arrangement. 
     In the description of each embodiment, each motor unit drives a lens as an optical element, but an optical element other than a lens such as a diaphragm may be driven. 
     The above embodiments can make compact an optical apparatus having a plurality of drivers for driving a plurality of optical elements. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2019-190709, filed on Oct. 18, 2019, which is hereby incorporated by reference herein in its entirety.