Abstract:
According to one embodiment, a lens driving apparatus comprises: a fixed member in which a first long groove is formed; a movable member including a lens and a second long groove; a first ball arranged between the first long groove and the second long groove, and configured to guide the movable member along the groove; a plurality of second balls arranged on a side opposite to a side of the first ball with the lens; a first actuator configured to generate a driving force for moving the movable member along the groove; and a second actuator for pivoting the movable member with respect to the fixed member. A pivoting center around which the movable member is pivoted with respect to the fixed member is a position of the first ball when the movable member is moved along the first long groove and the second long groove.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority from Japanese Patent Applications No. 2013-248612, filed Nov. 29, 2013; the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    Embodiments described herein relate generally to a lens driving apparatus for moving a movable member holding a lens with respect to a fixed member. 
       BACKGROUND 
       [0003]    As shown in FIGS. 4 and 5 of Jpn. Pat. Appln. KOKAI Publication No. 2011-85675, a pivot guide groove 124 which engages with a pivoting shaft 115 is formed in one end portion (a positive-side end in the X direction) of a moving frame 119. The pivoting shaft 115 is attached to a fixed member 102. When the moving frame 119 is translated during yaw correction, the pivot guide groove 124 slides with respect to the pivoting shaft 115. Also, the pivot guide groove 124 permits the moving frame 119 to pivot around the pivoting shaft 115 in the pitch correction direction. 
         [0004]    Consequently, a correction lens L7 held in the moving frame 119 can move in the pitch correction direction and yaw correction direction. 
         [0005]    Jpn. Pat. Appln. KOKAI Publication No. 2010-266739 has disclosed an anti-vibration actuator capable of supporting a lens so that the lens can move without any vibration. This anti-vibration actuator includes a support arm 17 for connecting a fixed plate 12 and moving frame 14, and a steel ball 18 clamped between the moving frame 14 and fixed plate 12. A flexible portion 17a of the support arm 17 is readily elastically deformable. When a horizontal driving force acts on the moving frame 14, a horizontal translation is permitted. When a vertical driving force acts on the moving frame 14, the moving frame 14 pivots around the flexible portion 17a and its vicinity. 
       SUMMARY 
       [0006]    A lens driving apparatus according to an aspect of the present invention comprises: a fixed member in which a first long groove is formed; a movable member including a second long groove formed in a position corresponding to a position where the first long groove is formed, and configured to move with respect to the fixed member in a plane perpendicular to an optical axis of a lens held by the movable member; a first ball arranged between the first long groove formed in the fixed member and the second long groove formed in the movable member, and configured to guide the movable member with respect to the fixed member along the first long groove and the second long groove; a plurality of second balls arranged on a side opposite to a side of the first ball with the lens formed in the movable member being sandwiched between the two sides, and configured to support movement of the movable member together with the first ball; a first actuator including a coil arranged in one of the fixed member and the movable member, and a magnet arranged in the other, and configured to generate a driving force for moving the movable member along the first long groove and the second long groove; and a second actuator including a coil arranged in one of the fixed member and the movable member, and a magnet arranged in the other, and configured to generate a driving force for pivoting the movable member with respect to the fixed member, wherein a pivoting center around which the movable member is pivoted with respect to the fixed member by the second actuator is a position of the first ball when the movable member is moved along the first long groove and the second long groove by the first actuator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective appearance view showing an image capturing apparatus according to an embodiment; 
           [0008]      FIG. 2  is an exploded perspective view of the image capturing apparatus shown in  FIG. 1 ; 
           [0009]      FIG. 3  is an exploded perspective view of a lens frame shown in  FIG. 2 ; 
           [0010]      FIG. 4  is a front view in which the lens frame shown in  FIG. 2  is viewed from an object side; 
           [0011]      FIG. 5  is a sectional view in which the lens frame shown in  FIG. 4  is cut along a line F5-F5; 
           [0012]      FIG. 6  is an exploded perspective view of an anti-vibration unit according to the first embodiment; 
           [0013]      FIG. 7  is a plan view in which the anti-vibration unit shown in  FIG. 6  is viewed from above; 
           [0014]      FIG. 8  is a sectional view in which the anti-vibration unit shown in  FIG. 7  is cut along a line F8-F8; 
           [0015]      FIG. 9  is a sectional view in which the anti-vibration unit shown in  FIG. 7  is cut along a line F9-F9; 
           [0016]      FIG. 10  is a sectional view in which the anti-vibration unit shown in  FIG. 7  is cut along a line F10-F10; 
           [0017]      FIG. 11  is a plan view in which a fixed member shown in  FIG. 6  is viewed from a movable member side; 
           [0018]      FIG. 12  is a perspective view of the fixed member shown in  FIG. 11 ; 
           [0019]      FIG. 13  is a perspective view in which a movable member shown in  FIG. 6  is obliquely viewed from below; 
           [0020]      FIG. 14  is a plan view in which an assembly obtained by attaching the movable member shown in  FIG. 13  to the fixed member shown in  FIG. 11  is viewed from above; 
           [0021]      FIG. 15  is a sectional view for explaining the functions of three balls shown in  FIG. 6 ; 
           [0022]      FIG. 16  is a perspective appearance view of an anti-vibration unit according to the second embodiment; and 
           [0023]      FIG. 17  is an exploded perspective view of the anti-vibration unit shown in  FIG. 16 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Embodiments of the present invention will be explained below with reference to the accompanying drawings. 
         [0025]    In the following explanation, a direction from a digital compact camera  100  (to be simply referred to as a camera  100  hereinafter) to an object will be called a front, and the opposite direction will be called a back. Also, in a state in which a user holds the camera  100  to aim it at an object (a state shown in  FIG. 1 ), a direction parallel to an optical axis O from a lens  102  of the camera  100  to the object will be called a Z direction, a horizontal direction perpendicular to the Z direction will be called an X direction, and a vertical direction perpendicular to the Z and X directions will be called a Y direction. 
         [0026]    The optical axis O of light entering the camera  100  through the lens  102  is bent downward at a right angle in the vertical direction (Y direction) by a reflecting mirror  14  ( FIG. 5 ) of a lens frame  10  (to be described later). Therefore, the thickness of the camera  100  in the front-back direction can be decreased. 
         [0027]    As shown in  FIG. 1 , the camera  100  includes a flat rectangular boxy housing  101 . The lens  102  is attached to the front side of the housing  101 . Also, a shutter button  104  is formed on the upper end of the housing  101 . 
         [0028]    As shown in  FIG. 2 , the camera  100  includes a rear cover  106  on the rear side of the housing  101 . A display panel  108  for displaying a captured image is formed on the rear cover  106 . In addition, a lens frame accommodating portion  105  for accommodating the lens frame  10  is formed inside the housing  101 . 
         [0029]      FIG. 3  is an exploded perspective view of the lens frame  10 .  FIG. 4  is a front view showing the lens frame  10  from the front.  FIG. 5  is a sectional view in which the lens frame  10  is cut along a line F5-F5 in  FIG. 4 . 
         [0030]    As shown in  FIG. 3 , the lens frame  10  includes a back cover  11 , and includes an anti-vibration unit accommodating portion  12  for accommodating an anti-vibration unit  20  (a lens driving apparatus) inside the back cover  11 . Also, as shown in  FIG. 5 , the lens frame  10  includes a plurality of lenses  13   a ,  13   b ,  13   c ,  13   d ,  13   e ,  13   f ,  13   g , and  13   h  along the optical axis O of light reflected downward by the reflecting mirror  14  (along the Y direction). The lens  13   h  positioned at the lowermost end along the optical axis O is an object to be moved in the anti-vibration unit  20 . 
         [0031]    Incident light from an object, which has entered the camera  100  through the lens  102 , is bent downward at a right angle by the reflecting mirror  14 , and captured by an image sensor  15  through the plurality of lenses  13   a  to  13   h . In this state, the anti-vibration unit  20  moves the lens  13   h  along a plane perpendicular to the optical axis O, so as to correct an image blur which occurs when a vibration is given to the camera  100 . In the camera  100  of this embodiment, the anti-vibration unit  20  moves the lens  13   h  along an XZ plane because the optical axis O is bent in the Y direction. 
         [0032]    The anti-vibration unit  20  according to the first embodiment will be explained below with reference to  FIGS. 6 ,  7 ,  8 ,  9 ,  10 ,  11 ,  12 ,  13 ,  14 , and  15 . 
         [0033]      FIG. 6  is an exploded perspective view of the anti-vibration unit  20 .  FIG. 7  is a plan view in which the anti-vibration unit  20  is viewed from above along the optical axis O.  FIG. 8  is a sectional view in which the anti-vibration unit  20  is cut along a line F8-F8 in  FIG. 7 .  FIG. 9  is a sectional view in which the anti-vibration unit  20  is cut along a line F9-F9 in  FIG. 7 .  FIG. 10  is a sectional view in which the anti-vibration unit  20  is cut along a line F10-F10 in  FIG. 7 .  FIG. 11  is a plan view in which a fixed member  24  is viewed from above along the optical axis O.  FIG. 12  is a perspective view of the fixed member  24 .  FIG. 13  is a perspective view in which a movable member  22  is obliquely viewed from below.  FIG. 14  is a plan view in which an assembly  30  obtained by attaching the movable member  22  shown in  FIG. 13  to the fixed member  24  shown in  FIG. 11  is viewed from above.  FIG. 15  is a sectional view for explaining the functions of three balls  36 ,  37 , and  38  which support the movable member  22  such that the movable member  22  can move with respect to the fixed member  24 . Note that in  FIGS. 7 ,  8 ,  9 , and  10 , a flexible printed circuit board  21  (to be simply referred to as an FPC  21  hereinafter) of the anti-vibration unit  20  is not shown. 
         [0034]    As shown in  FIG. 6 , the anti-vibration unit  20  includes the movable member  22  holding the lens  13   h , the fixed member  24  (a first fixed member) which is arranged below the movable member  22  and supports the movable member  22  so that the movable member  22  can move along the XZ plane, and a coil frame  26  (a second fixed member) arranged above the movable member  22 . That is, the movable member  22  is arranged in a non-contact state in the space between the fixed member  24  and coil frame  26 . The movable member  22 , fixed member  24 , and coil frame  26  are arranged such that their longitudinal directions are parallel to the X direction. 
         [0035]    The lens  13   h  is held in almost the center of the movable member  22  in the longitudinal direction. The coil frame  26  holds two coils  31  and  32  spaced apart from each other on the two sides in the longitudinal direction so as to sandwich the lens  13   h  between them. Also, the movable member  22  includes three magnets  33 ,  34 , and  35  which oppose the coils  31  and  32 . In this embodiment, the coils  31  and  32  are formed in the coil frame  26 , and the magnets  33  and  34  are formed in the movable member  22 . However, it is also possible to form the coils  31  and  32  in the movable member  22 , and the magnets  33  and  34  in the coil frame  26 . 
         [0036]    In this embodiment, the magnet  33  formed on a one-end side of the movable member  22  opposes the coil  31 , and the two magnets  34  and  35  formed on an other-end side of the movable member  22  so as to sandwich the lens  13   h  between the magnet  33  and the magnets  34  and  35  oppose the coil  32 . The two magnets  34  and  35  are divided in order to maintain the mechanical strength of the movable member  22 , but they may also be integrated into one magnet like the magnet  33 . 
         [0037]    The coil frame  26  is fixed to the fixed member  24  so as not to contact the movable member  22 . The movable member  22  is not in contact with the fixed member  24  as well. When fixing the coil frame  26  to the fixed member  24 , claws  24   a  and  24   b  projecting from the two ends of the fixed member  24  in the longitudinal direction respectively engage with engaging holes  27   a  and  27   b  formed in tongue pieces  26   a  and  26   b  projecting downward from the two ends of the coil frame  26  in the longitudinal direction. The FPC  21  is attached to the coil frame  26  so as to be connected to the coils  31  and  32 . 
         [0038]    The coil  31  and magnet  33  on a one-end side of the lens  13   h  form a voice coil motor (VCM) for a straight motion, and function as a first driver (first actuator) for driving the movable member  22  (i.e., the lens  13   h ) in the X direction. Also, the coil  32  and magnets  34  and  35  on an other-end side form a voice coil motor (VCM) for a pivotal motion, and function as a second driver (second actuator) for driving the lens  13   h  in nearly the Z direction by swinging the movable member  22 . The first and second drivers function as a driving means for moving the lens  13   h  in a desired direction along the XZ plane in cooperation with each other. 
         [0039]    Electric currents controlled by a controller (not shown) are supplied to the coils  31  and  32  via the FPC  21 . By controlling the direction of an electric current to be supplied to the coil  31 , it is possible to change the direction of a magnetic flux to be applied to the magnet  33 , and bidirectionally move the movable member  22  in the longitudinal direction (X direction). Also, by controlling the direction of an electric current to be supplied to the coil  32 , it is possible to change the direction of a magnetic flux to be applied to the magnets  34  and  35 , and swing the movable member  22  to the two sides in the short-length direction (Z direction). In other words, the postures of the two coils  31  and  32  and three magnets  33 ,  34 , and  35  are decided so as to enable the operation of the movable member  22  along the XZ plane as described above. 
         [0040]    The three balls  36 ,  37 , and  38  are arranged between the movable member  22  and fixed member  24 . The ball  36  (a first ball) which is only one ball having a large diameter among the three balls functions as a central sphere which gives a pivotal center to the movable member  22 . As shown in  FIG. 8 , the ball  36  is arranged on a one-end side of the movable member  22  (the fixed member  24 ) so as to be sandwiched between a groove  41  (a second long groove) of the movable member  22  and a groove  42  (a first long groove) of the fixed member  24 . The two grooves  41  and  42  are grooves extending in the same direction so as to oppose each other, and having V-shaped sections. 
         [0041]    The groove  41  of the movable member  22  is formed on the lower-surface side of a projection  22   a  projecting from one end of the movable member  22  in a direction away from the lens  13   h . That is, the groove  41  is formed in the end portion of the movable member  22 , which is farthest from the lens  13   h . As shown in  FIG. 13 , the groove  41  is extended along the longitudinal direction (X direction) of the movable member  22 . 
         [0042]    On the other hand, as shown in  FIG. 12 , the groove  42  of the fixed member  24  is also extended along the longitudinal direction (X direction) of the fixed member  24 . Note that the two grooves  41  and  42  are each closed at the two ends in the longitudinal direction, thereby preventing the removal of the ball  36 . 
         [0043]    The two remaining balls  37  and  38  function as swinging spheres (second balls) for swinging the movable member  22  around the above-described, large-diameter ball  36  along the XZ plane. The two balls  37  and  38  are spaced apart from each other along the circumference around the ball  36 , on the side opposite to the side of the ball  36  with the lens  13   h  being sandwiched between them. 
         [0044]    The two balls  37  and  38  are respectively accommodated in rectangular recesses  43  and  44  formed in the upper surface of the fixed member  24 . The balls  37  and  38  arranged in the recesses  43  and  44  are pressed by flat pads  45  and  46  formed on the lower surface of the movable member  22 . Since the recesses  43  and  44  of the fixed member  24  have a predetermined depth, the removal of the balls  37  and  38  can be prevented by pressing them by the flat pads  45  and  46 . 
         [0045]    Note that the large-diameter ball  36  is in contact at two points with the two walls opposing each other at a right angle of the groove  41  of the movable member  22 , and in contact at two points with the two walls of the groove  42  of the fixed member  24 . That is, the ball  36  is in contact with the grooves  41  and  42  at four points. Also, the two remaining balls  37  and  38  are respectively in point-contact with the bottom surfaces of the recesses  43  and  44  of the fixed member  24 , and are respectively in point-contact with the pads  45  and  46  of the movable member  22 . That is, the two balls  37  and  38  are respectively in contact with the recesses  43  and  44  and pads  45  and  46  at two points. 
         [0046]    Three tension springs  51 ,  52 , and  53  are extended between the movable member  22  and fixed member  24 . The three tension springs  51 ,  52 , and  53  function as a biasing means for biasing the movable member  22  and fixed member  24  in a direction in which they approach each other. 
         [0047]    The tension spring  51  is arranged on the side opposite to the side of the large-diameter ball  36  with the lens  13   h  being sandwiched between them. The two remaining tension springs  52  and  53  are arranged on the side opposite to the side of the tension spring  51  with the lens  13   h  being sandwiched between them. The three tension springs  51 ,  52 , and  53  are arranged in positions forming a first triangle. The three balls  36 ,  37 , and  38  described above are arranged in positions forming a second triangle which points in a direction opposite to that of the first triangle. 
         [0048]    In a general image stabilization apparatus, tension springs are arranged near spherical spacers arranged between a movable member and fixed member. In this embodiment, however, the tension spring  51  is arranged on the side in which the two balls  37  and  38  are arranged, and the two tension springs  52  and  53  are arranged on the side in which the ball  36  is arranged, with the lens  13   h  being sandwiched between the two sides. 
         [0049]    One end of each of the tension springs  51 ,  52 , and  53  is slightly extended and hooked on one of hooks  54 ,  55 , and  56  projecting from the movable member  22 . The other end of each of the tension springs  51 ,  52 , and  53  is slightly extended and hooked on one of hooks  57 ,  58 , and  59  formed on the fixed member  24 . 
         [0050]    Consequently, the movable member  22  is pulled toward the fixed member  24  so as to press the three balls  36 ,  37 , and  38  sandwiched between them. In this state, the large-diameter ball  36  is movable in the X direction along the two grooves  41  and  42 , and the movable member  22  is swingable around the ball  36 . In other words, the two grooves  41  and  42  prohibit the movement of the movable member  22  to the Z-direction component in the position of the ball  36 , and permit pivoting around the ball  36  and sliding in the X direction. 
         [0051]      FIG. 14  is a plan view showing the assembly  30  combining the movable member  22  and fixed member  24 , in which broken lines indicate a triangle connecting the centers of the three balls  36 ,  37 , and  38 , and another triangle connecting the centers of the three tension springs  51 ,  52 , and  53 . As shown in  FIG. 14 , these two triangles overlap each other in opposite directions. Note that the barycenter of one triangle exists in the other triangle, and the barycenter of the other triangle exists in one triangle. 
         [0052]    As shown in  FIG. 14 , the tension spring  51  is arranged on the opposite side spaced apart from the pivoting center of the movable member  22 , i.e., on the side opposite to the side of the large-diameter ball  36  with the lens  13   h  being sandwiched between them. This makes it possible to relatively decrease (weaken) the restoring force of the tension spring  51  when the movable member  22  pivots around the ball  36 . By contrast, if the two tension springs  52  and  53  are arranged on the side opposite to the side of the ball  36  with the lens  13   h  being sandwiched between them, the restoring force of the tension springs  52  and  53  increases when the movable member  22  pivots around the ball  36 . 
         [0053]    That is, by arranging the tension spring  51  in a position far from the ball  36  (the pivoting center), it is possible to decrease the moment based on the restoring force of the tension spring  51 , and suppress the resonance frequency of the anti-vibration unit  20 . In this embodiment, therefore, it is possible to accurately control the operation of the anti-vibration unit  20 , and improve the anti-vibration performance. 
         [0054]    Note that this embodiment shown in  FIG. 14  adopts the layout in which the ball  36  is arranged outside the magnet  33 , the two tension springs  52  and  53  are arranged between the magnet  33  and lens  13   h , and the two balls  37  and  38  and the tension spring  51  are arranged outside the two magnets  34  and  35 . However, the present invention is not limited to this, and it is possible to freely change the X-direction layout of the magnets  33 ,  34 , and  35 , balls  36 ,  37 , and  38 , and tension springs  51 ,  52 , and  53 . That is, the tension spring  51  need only be arranged on the side opposite to the side of the ball  36  for a straight motion with the lens  13   h  being sandwiched between them. 
         [0055]    Left side diagram of  FIG. 15  is a partially enlarged view of the main components shown  FIG. 8 . Right side diagram of  FIG. 15  is a partially enlarged view of the main components shown in  FIG. 9 . The left and Right side diagram of  FIG. 15  are illustrated side by side by matching the positions in the Y direction, in order to facilitate understanding the Y-direction positional relationship between the three balls  36 ,  37 , and  38 . 
         [0056]    As shown in  FIG. 15 , the centers of the three balls  36 ,  37 , and  38  are arranged on a central plane S0 (a first plane) parallel to the XZ plane, the two points at which the large-diameter ball  36  is in contact with the groove  41  of the movable member  22  and the points at which the two balls  37  and  38  are in contact with the pads  45  and  46  of the movable member  22  are arranged on a plane S1 (a second plane) parallel to the XZ plane, and the two points at which the large-diameter ball  36  is in contact with the groove  42  of the fixed member  24  and the points at which the two balls  37  and  38  are in contact with the bottom surfaces of the recesses  43  and  44  of the fixed member  22  are arranged on a plane S2 (a third plane) parallel to the XZ plane. 
         [0057]    In other words, in this embodiment, the diameter of the ball  36  is so designed that the centers of the three balls  36 ,  37 , and  38  are arranged on the same plane S0, the four points at which the three balls  36 ,  37 , and  38  are in contact with the movable member  22  are arranged on the plane S1 parallel to the plane S0, and the four points at which the three balls  36 ,  37 , and  38  are in contact with the fixed member  24  are arranged on the plane S2 parallel to the plane S0. In this embodiment, the two grooves  41  and  42  holding the ball  36  each have two walls intersecting each other at a right angle. Therefore, the diameter of the ball  36  is designed to be √2 times the diameter of the two balls  37  and  38 . 
         [0058]    Accordingly, when the movable member  22  moves along the XZ plane in accordance with driving control of the anti-vibration unit  20 , friction forces act on the circumferential surfaces of the balls  36 ,  37 , and  38  in the two parallel planes S1 and S2. Since this stabilizes the balance of the moments of the friction forces acting on the circumferential surfaces of the balls  36 ,  37 , and  38 , the occurrence of resonance can be suppressed. 
         [0059]    As described above, the first embodiment adopts the arrangement in which the two grooves  41  and  42  extending in the X direction hold the ball  36  as the pivoting center of the movable member  22 . This makes it possible to accurately control the straight motion in the X direction and the pivoting motion around the ball  36  of the movable member  22  without any play between the circumferential surface of the ball  36  and the wall surfaces of the grooves  41  and  42 . Especially in this embodiment, the circumferential surface of the large-diameter ball  36  is in contact with each of the grooves  41  and  42  at two points. Therefore, it is possible to disperse the load acting between the ball  36  and groove  41  ( 42 ), and decrease the friction force. This can make the above-described straight motion and pivoting motion smoother. 
         [0060]    Also, in this embodiment, the tension spring  51  is arranged in a position farthest from the ball  36  as the pivoting center of the movable member  22 . This makes it possible to weaken the restoring force when the movable member  22  swings from the home position, and decrease the resonance frequency of the anti-vibration unit  20  in a θ direction. 
         [0061]    Next, an anti-vibration unit  60  according to the second embodiment will be explained with reference to  FIGS. 16 and 17 . 
         [0062]      FIG. 16  is a perspective appearance view in which the anti-vibration unit  60  is viewed from below.  FIG. 17  is an exploded perspective view of the anti-vibration unit  60 . The anti-vibration unit  60  has almost the same structure as that of the anti-vibration unit  20  of the first embodiment described above, except that the anti-vibration unit  60  includes two plates  61  and  62  formed by a magnetic material such as iron, instead of the three tension springs  51 ,  52 , and  53 . In this embodiment, therefore, the same reference numerals as in the first embodiment denote constituent elements functioning in the same ways as in the first embodiment, and a detailed explanation thereof will be omitted. 
         [0063]    The two plates  61  and  62  are arranged to oppose magnets  33 ,  34 , and  35  on the lower-surface side of a fixed member  24 . The plate  61  is fixed to the fixed member  24  on the side opposite to the side of the magnet  33 , and the plate  62  is fixed to the fixed member  24  on the side opposite to the side of the magnets  34  and  35 . The plates  61  and  62  made of the magnetic material function as biasing means for attracting a movable member  22  to the fixed member  24  by magnetic attracting forces generated between the plates  61  and  62  and the opposing magnets  33 ,  34 , and  35 . 
         [0064]    In this embodiment, two grooves  41  and  42  hold a large-diameter ball  36 , and this enables a straight motion and pivoting motion without any backlash between the movable member  22  and fixed member  24 , as in the above-described first embodiment. 
         [0065]    Also, this embodiment does not use the tension springs  51 ,  52 , and  53  unlike the first embodiment. This obviates the need to consider the restoring force of a spring, which is generated along the XZ plane, and makes it possible to increase the degree of freedom of the layout. 
         [0066]    The present invention has been explained above based on the embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and applications are of course possible within the spirit and scope of the invention. 
         [0067]    For example, in the above-described embodiments, the case in which the grooves  41  and  42  holding the large-diameter ball  36  have the V-shaped sections has been explained. However, the present invention is not limited to this, and each groove can have any sectional shape as long as the groove has a shape in contact with the circumferential surface of the ball  36  at two points, and extends in the X direction. For example, a groove having a U-shaped section can be used. 
         [0068]    Furthermore, in the above-described embodiments, the structure in which the movable member  22  holding the lens  13   h  is moved along the XZ plane with respect to the fixed member  24  has been explained. However, the present invention is not limited to this, and the movable member holding the image sensor  15  may also be moved with respect to the fixed member  24 . 
         [0069]    Other inventions will be described below. 
         [0000]    [1] There is provided a driving apparatus including 
         [0070]    a movable member holding an object to be moved, 
         [0071]    a fixed member formed to oppose the movable member, 
         [0072]    a central sphere arranged between the movable member and fixed member, 
         [0073]    a rolling member arranged between the movable member and fixed member on the side opposite to the side of the central sphere with the object to be moved being sandwiched between them, 
         [0074]    a biasing means for biasing the movable member and fixed member in a direction in which they approach each other, so as to press the central sphere and rolling member, 
         [0075]    first and second grooves respectively formed in the movable member and fixed member, and accommodating the central sphere such that the central sphere can move close to and away from the object to be moved, and 
         [0076]    a driving means for moving the movable member with respect to the fixed member. 
         [0000]    [2] There is provided the apparatus according to [1], wherein the first and second grooves are grooves extending in the same direction so as to oppose each other, and having V-shaped sections.
 
[3] There is provided the apparatus according to [2], wherein the first groove is formed in one end of the movable member, which is spaced apart from the object to be moved.
 
[4] There is provided the apparatus according to [2], wherein the driving means includes a first driver for moving the movable member along the first and second grooves, and a second driver for pivoting the movable member around the central sphere arranged in the first and second grooves.
 
[5] There is provided the apparatus according to [2], wherein
 
         [0077]    the rolling member includes a plurality of swinging spheres arranged apart from each other along a circumference around the central sphere, and 
         [0078]    a first plane passing through the center of the central sphere and the center of each swinging sphere, a second plane passing through two points at which the central sphere is in contact with the first groove of the movable member and a point at which each swinging sphere is in contact with the movable member, and a third plane passing through two points at which the central sphere is in contact with the second groove of the fixed member and a point at which each swinging sphere is in contact with the fixed member are parallel to each other. 
         [0000]    [6] There is provided the apparatus according to [1], wherein the biasing means includes a tension spring which biases the movable member and fixed member in a direction in which they approach each other, on the side opposite to the side of the central sphere with the object to be moved being sandwiched between them.
 
[7] There is provided a driving apparatus including
 
         [0079]    a movable member holding an optical element or image sensor, 
         [0080]    a fixed member formed near the movable member in the optical-axis direction of the optical element or image sensor, 
         [0081]    a central sphere which is arranged between the movable member and fixed member at a position spaced apart from the optical element or image sensor, and gives a pivoting center, 
         [0082]    a plurality of swinging spheres arranged between the movable member and fixed member on the side opposite to the side of the central sphere with the optical element or image sensor being sandwiched between them, 
         [0083]    a biasing means for biasing the movable member and fixed member in a direction in which they approach each other so as to press the central sphere and swinging spheres, 
         [0084]    first and second grooves respectively formed in the movable member and fixed member so as to oppose each other, and accommodating the central sphere such that the central sphere can move close to and away from the optical element or image sensor, 
         [0085]    a straight driving unit for moving the movable member in a first direction along the first and second grooves, and 
         [0086]    a pivotal driving unit for pivoting the movable member around the central sphere arranged in the first and second grooves. 
         [0000]    [8] There is provided the apparatus according to [7], wherein the first and second grooves are grooves extending in the first direction so as to oppose each other, and having V-shaped sections.
 
[9] There is provided the apparatus according to [8], wherein the first groove is formed in one end of the movable member, which is spaced apart from the optical element or image sensor.
 
[10] There is provided the apparatus according to [8], wherein a first plane passing through the center of the central sphere and the center of each swinging sphere, a second plane passing through two points at which the central sphere is in contact with the first groove of the movable member and a point at which each swinging sphere is in contact with the movable member, and a third plane passing through two points at which the central sphere is in contact with the second groove of the fixed member and a point at which each swinging sphere is in contact with the fixed member are parallel to each other.
 
[11] There is provided the apparatus according to [7], wherein the biasing means includes a tension spring which biases the movable member and fixed member in a direction in which they approach each other, on the side opposite to the side of the central sphere with the optical element or image sensor being sandwiched between them.
 
[12] There is provided an image capturing apparatus including
 
         [0087]    an image sensor, 
         [0088]    an optical element which forms an image of an object on the image sensor, 
         [0089]    a movable member holding the optical element or image sensor, 
         [0090]    a fixed member formed near the movable member in the optical-axis direction of the optical element or image sensor, 
         [0091]    a central sphere which is arranged between the movable member and fixed member at a position spaced apart from the optical element or image sensor, and gives a pivoting center, 
         [0092]    a plurality of swinging spheres arranged between the movable member and fixed member on the side opposite to the side of the central sphere with the optical element or image sensor being sandwiched between them, 
         [0093]    a biasing means for biasing the movable member and fixed member in a direction in which they approach each other so as to press the central sphere and swinging spheres, 
         [0094]    first and second grooves respectively formed in the movable member and fixed member so as to oppose each other, and accommodating the central sphere such that the central sphere can move close to and away from the optical element or image sensor, 
         [0095]    a straight driving unit for moving the movable member in a first direction along the first and second grooves, and 
         [0096]    a pivotal driving unit for pivoting the movable member around the central sphere arranged in the first and second grooves. 
         [0000]    [13] There is provided the apparatus according to [12], wherein the first and second grooves are grooves extending in the first direction so as to oppose each other, and having V-shaped sections.
 
[14] There is provided the apparatus according to [13], wherein the first groove is formed in one end of the movable member, which is spaced apart from the optical element or image sensor.
 
[15] There is provided the apparatus according to [13], wherein a first plane passing through the center of the central sphere and the center of each swinging sphere, a second plane passing through two points at which the central sphere is in contact with the first groove of the movable member and a point at which each swinging sphere is in contact with the movable member, and a third plane passing through two points at which the central sphere is in contact with the second groove of the fixed member and a point at which each swinging sphere is in contact with the fixed member are parallel to each other.
 
[16] There is provided the apparatus according to [12], wherein the biasing means includes a tension spring which biases the movable member and fixed member in a direction in which they approach each other, on the side opposite to the side of the central sphere with the optical element or image sensor being sandwiched between them.