Abstract:
A lens apparatus which enables to reduce size is disclosed. The lens apparatus has a first member which is movable in the optical axis direction and holds a first lens unit; a second member which holds a second lens unit and the first member; a first motor which is mounted to the second member and generates a driving force for driving the first member; a diaphragm unit which is mounted to the second member and performs open and close operations; a second motor which is mounted to the second member and generates a driving force for driving the diaphragm unit; and a guide member which is mounted to the second member and guides the first member in the optical axis direction.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention concerns a lens apparatus for forming a object image on an image pickup element and particularly concerns the positioning of a motor, incorporated in a lens apparatus, etc. 
   2. Description of the Related Art 
   Conventionally, collapsible lens apparatuses, with which the total lens apparatus length is made variable between a usage state, wherein a plurality of image taking lenses are positioned at desirable lens intervals during image taking, and a housed state, wherein the lens intervals and interval with respect to an image pickup plane are narrowed, have been used popularly in digital still cameras, etc. 
   The varying of the total lens apparatus length is carried out by means of cams, helicoids, and other moving mechanisms to set the lens apparatus to an appropriate configuration. A zoom lens apparatus can also be arranged, with which the focal length is varied by driving a plurality of lens units separately. 
     FIGS. 11 and 12  are sectional views including the optical axis of a conventional lens apparatus, with  FIG. 11  showing the state of the lens apparatus in the non-image-taking state, in which the lens apparatus is housed in a housing region of a main body of camera.  FIG. 12  shows the state of the lens apparatus during an image taking, wherein the lens apparatus is driven from the housing region to an image taking region. 
   In  FIGS. 11 and 12 , Reference Numeral  101  denotes an image pickup element. The image pickup element  101  is a CCD, with  101   a  being an image pickup plane and  101   b  being a protective glass. Reference Numeral  102  denotes a CCD mounting base plate, which holds the image pickup element  101  and holds the respective parts that make up the lens apparatus to be described later. Reference Numeral  103  denotes an optical LPF (low pass filter), which makes use of the birefringence effect of quartz to repress the occurrence of luminance moiré and false colors. Reference Numeral  104  denotes a first lens unit that forms the optical system of the lens apparatus. Reference Numeral  105  denotes likewise a second lens unit and Reference Numeral  106  denotes a third lens unit. 
   Reference Numeral  107  denotes a fixed barrel with a substantially cylindrical shape that is fixed to the CCD mounting base plate  102 . Reference Numeral  108  denotes a cam barrel with substantially cylindrical shape. On the outer peripheral surface of the cam barrel  108 , a protrusion that serves as a cam follower is formed. A cam is formed on the inner peripheral surface of the fixed barrel  107 , and engages with the cam follower  108   a  of the cam barrel  108 . Upon application of a rotating force by an unillustrated driving portion, the cam barrel  108  moves in the optical axis direction while rotating around the optical axis in accordance with the cam track of the fixed barrel  107 . 
   Reference Numeral  109  denotes a rectilinear barrel, which is rotatably engaged to the inner peripheral surface of the cam barrel  108 . Reference Numeral  109   a  denotes a claw-shaped portion, which prevents the falling off of the rectilinear barrel  109  from the cam barrel  108 . Reference Numeral  109   b  denotes a protrusion, extending in the radial direction of the lens apparatus from the rectilinear barrel  109 . Reference numeral  107   a  denotes a rectilinear groove portion, which is formed in the inner peripheral surface of the fixed barrel  107  so as to extend in the optical axis direction. By the engagement action of the protrusion  109   b  and the rectilinear groove portion  107   a , the rectilinear barrel  109  moves in the optical axis direction without rotating around the optical axis in accordance with the rotation operation of the cam barrel  108 . 
   Reference Numeral  110  denotes a first lens unit holding barrel, which holds the first lens unit  104 . Reference Numeral  110   a  denotes a first cam follower, which is fixed to the first lens unit holding barrel  110 . The first cam follower  110   a  moves along the cam track of a first cam that is formed in the inner peripheral surface of the cam barrel  108 . Reference Numeral  111  denotes a second lens unit holding barrel, which holds the second lens unit  105 . As with the first lens unit holding barrel  110 , the second lens unit holding barrel  111  is provided with a second cam follower, which protrudes outward in the radial direction. And the second cam follower moves along the track of a second cam formed in the inner peripheral surface of the cam barrel  108 . 
   Furthermore, in the rectilinear barrel  109 , an opening that extends in the optical axis direction is formed, and by the opening engaging with the first cam follower, the first lens unit holding barrel  110  moves rectilinearly. And the first lens unit holding barrel  110  moves, without rotating, in the optical axis direction along the first cam formed in the inner side of the cam barrel  108  in accordance with the rotation operation of the cam barrel  108 . By the above arrangement, the first and second lens unit holding barrels  110  and  111  can be moved from the housing region to the image taking region. 
   Reference Numeral  112  denotes a third lens unit holding barrel, which holds the third lens unit  106 . The third lens unit  106  is a lens unit for focusing, and the focusing operation is enabled by moving the third lens unit holding barrel  112  in the optical axis direction. 
   Reference Numeral  113  denotes a guide rod, which is fixed to the CCD mounting base plate  102  and supports the third lens unit holding barrel  112  in a manner enabling movement along the optical axis. Reference Numeral  114   a  denotes a screw, which rotates upon receiving a driving force from a motor  114 . Reference Numeral  115   a  denotes a bearing of the guide rod  113  and  115   b  denotes a bearing, which supports the front end of the screw  114   a . The bearings  115   a  and  115   b  are fixed to the CCD mounting base plate  102 . A nut, which engages with the screw  114   a , is supported in an unrotatable manner on the third lens unit holding barrel  112 , and the third lens unit holding barrel  112  is thereby enabled to be moved in the optical axis direction by the motor  114  to perform the focusing operation. 
   With such an image taking apparatus having a housing region for housing a lens apparatus, portability and compact housing features are required in particular, and to be specific, the lens apparatus must be made compact in the radial direction and the total length of the lens apparatus in the collapsed state must be made as short as possible. 
   Thus there are cases where, in the collapsed state, the second lens unit holding barrel  111  is housed upon entering the range of movement of the third lens unit holding barrel  112  as shown in  FIG. 11 . With such an arrangement, in order to avoid interference (overlapping) with the guide rod  113 , the screw  114   a , the bearings  115   a  and  115   b  thereof, and other various parts for enabling the movement of the third lens unit holding barrel  112 , openings must be provided in parts of the second lens unit holding barrel  111 . 
     FIG. 13  shows the second lens unit holding barrel  111  as viewed from the front. As viewed from the front, the second lens unit holding barrel  111  has openings provided at three locations of its periphery in order to avoid interference (overlapping) with the bearing  115   b  of the screw  114   a , the bearing  115   a  of the guide rod  113 , and a bearing (not shown) for a rotation stopping rod for restraining the rotation of the third lens unit holding barrel  112  around the guide rod  113 . 
   However, since the proportion of the area of the second lens unit holding barrel  111  that is taken up by the openings is large, the holding of the lenses may become unstable due to inadequate strength and lead to degradation of the optical performance. Leakage of light rays may also occur. 
   Here, leakage of light rays means the phenomenon in which light besides the light flux used for image taking reach the image pickup element. In the conventional lens apparatus, there are cases where light rays, which have become incident at a predetermined angle onto the first lens unit  104 , become reflected by the inner peripheral surface of the rectilinear barrel  109  and become incident on the image pickup element  101  without passing through the second lens unit  105 . However, since there are large openings in the second lens unit holding barrel  111 , leakage of light rays could not be repressed and this represses the making of the lens apparatus compact. 
   On the other hand, if ribs are provided to increase the strength of the second lens unit holding barrel  111  that has openings, the lens apparatus becomes large. The meaning of designing the second lens unit holding barrel  111  so that it enters the movement range of the third lens unit holding barrel  112  in the collapsed state to enable the making of the lens apparatus compact is thereby lost. 
   Also, if the component parts of the third lens unit holding barrel  112  are positioned so as to avoid overlapping with the second lens unit holding barrel  111 , the lens apparatus may become large in the radial direction. 
   This invention proposes an optimal positioning of the respective parts inside the lens apparatuses for resolving the above issues, and an object thereof is to realize the making of the lens apparatus compact. 
   SUMMARY OF THE INVENTION 
   A lens apparatus of one aspect of this invention is a lens apparatus comprising a first member which is movable in the optical axis direction and holds a first lens unit; a second member which holds a second lens unit and the first member; a first motor which is mounted to the second member and generates a driving force for driving the first member; a diaphragm unit which is mounted to the second member and performs open and close operations; a second motor which is mounted to the second member and generates a driving force for driving the diaphragm unit; and a guide member which is mounted to the second member and guides the first member in the optical axis direction. 
   In a case where a region of the second member viewed in the optical axis direction is divided into four regions by lines extending from the optical axis to positions corresponding to four corners of the image pickup element, the output shaft of the first motor is positioned in a first region of the four regions, the output shaft of the second motor is positioned in a second region, and the guide member is positioned in a third region. 
   An image taking apparatus of one aspect of this invention comprises the lens apparatus described above and an image pickup element which photoelectrically converts an object image formed by the lens apparatus. 
   The characteristics of the lens apparatus and the image taking apparatus according to this invention shall become clearer by the following detailed description of the embodiment with reference to the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a sectional view including the optical axis of a lens apparatus according to an embodiment of this invention, in the collapsed state. 
       FIG. 2  is a sectional view including the optical axis of the lens apparatus in the image taking state. 
       FIG. 3  is an exploded perspective view of a second barrel. 
       FIG. 4  is a perspective view of a focusing unit. 
       FIG. 5  is a perspective view of a shutter drive source and shutter blades. 
       FIG. 6  is a perspective view of a shutter unit in the closed state. 
       FIG. 7  shows a construction of a diaphragm mechanism in the open state. 
       FIG. 8  shows a construction of the diaphragm mechanism in the closed state. 
       FIG. 9  is an exploded perspective view of a correction mechanism for correcting the tilting of an image pickup plane. 
       FIG. 10  is a diagram showing a second barrel on which a stepping motor, etc. are mounted, viewed along the optical axis direction. 
       FIG. 11  is a sectional view including the optical axis of a conventional lens apparatus in the collapsed state. 
       FIG. 12  is a sectional view including the optical axis of the conventional lens apparatus in the image taking state. 
       FIG. 13  is a front view of a second barrel in the conventional lens apparatus. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   An embodiment of this invention shall now be described. 
     FIG. 1  is a sectional view along the optical axis of a lens apparatus in the collapsed state, and  FIG. 2  is a sectional view along the optical axis of the lens apparatus in the image taking state. 
   The optical system of the lens apparatus of this embodiment comprises a first lens unit  1  serving as a compensator lens, a second lens unit  2  serving as a variator lens, a third lens unit  3  serving as a focusing lens, and a fourth lens unit  4  serving as a fixed relay lens. 
   Reference Numeral  5  denotes a holding plate, holding an image pickup element  6 , which, for example, is a CCD sensor or a CMOS image sensor. In the present embodiment, a CCD sensor is used as the image pickup element  6 . 
   Reference Numeral  7  denotes an optical low-pass filter (referred to hereinafter as “optical LPF”), which represses the occurrence of luminance moiré and false colors and is positioned at the object side of the image pickup element  6 . Reference Numeral  8  denotes a cover barrel with cylindrical shape, which is fixed to the holding plate  5  by means of unillustrated machine screws. 
   Reference Numeral  9  denotes a drive gear, which engages with a gear  10   a , formed on the outer circumferential face of a drive barrel  10 , and transmits the rotational force of an unillustrated motor to the drive barrel  10 . The drive gear  9  is rotatably supported on the cover barrel  8  and the holding plate  5 . 
   The drive barrel  10  is formed to a cylindrical shape and has rectilinear groove portions  10   b , which extend along the optical axis direction, formed at three locations in the circumferential direction of its inner circumferential face. 
   At the inner side of the drive barrel  10 , a fixed barrel  11 , which is fixed to the cover barrel  8  and the holding plate  5 , is housed. In the fixed barrel  11 , a through hole portion  11   b  is formed, which extends incliningly with respect to the circumferential direction and is for passing through a drive cam pin  12   b  that is formed on the outer circumferential face of a moving cam barrel  12 , to be described below. In the fixed barrel  11 , a cam groove portion  11   a  is formed, which extends incliningly with respect to the circumferential direction. A cam follower pin  12   a , provided on the outer circumferential face of the moving cam barrel  12  to be described below, engages with the cam groove portion  11   a.    
   In the inner circumferential face of the moving cam barrel  12 , a groove portion  12   c , which extends incliningly with respect to the circumferential direction, is formed. And a protrusion  13   a , formed on the outer circumferential face of a rectilinear barrel  13  to be described later, engages with the groove portion  12   c.    
   At the rear end portion in the optical axis direction of the outer circumferential face of the rectilinear barrel  13 , protrusions  13   b  are provided at equal intervals at three locations in the circumferential direction, and these protrusions  13   b  engage with rectilinear groove portions  11   c , which are formed in the inner circumferential face of the fixed barrel  11  and extend in the optical axis direction. 
   With the above-described arrangement, when the drive barrel  10  starts to rotate around the optical axis by receiving the driving force from the drive source, the moving cam barrel  12  rotates around the optical axis by the engagement of the drive cam pin  12   b  and the rectilinear groove portion  10   b  and moves in the optical axis direction by the engagement of the cam follower pin  12   a  and the cam groove portion  11   a.    
   Furthermore, since the protrusion  13   a  and the protrusions  13   b  respectively engages with the groove portion  12   c  formed in the moving cam barrel  12  and the rectilinear groove portions  11   c  formed in the fixed barrel  11 , during the rotation of the moving cam barrel  12 , the rectilinear barrel  13  moves in the optical axis direction without rotating around the optical axis. 
   The respective lens unit holding barrels shall now be described. 
   On the outer circumferential face of the second lens unit holding barrel  14  that holds the second lens unit  2 , cam follower pins  14   a  are formed at equal intervals at three locations in the circumferential direction. The cam follower pins  14   a  pass through the through hole portions  13   c  formed in the rectilinear barrel  13  and engage with the groove portions  12   d  of the moving cam barrel  12 . 
   Also, a third lens unit holding barrel  15 , a shutter unit  16 , and a diaphragm unit  17 , which, along with the second lens unit holding barrel  14 , make up a second barrel  18  (the construction in the area surrounded by the dotted line in  FIGS. 1 and 2 ), are incorporated in the second lens unit holding barrel  14 , the details of these components shall be described later. 
   At the inner side of the rectilinear barrel  13 , a first cam barrel  19  is housed. On the outer circumferential face of the first cam barrel  19 , a follower pin  19   a , which has a tapered front end portion, and a drive pin  19   b  are provided. The follower pin  19   a  engages with a tapered cam  13   c , which is formed in the inner circumferential face of the rectilinear barrel  13  and extends incliningly with respect to the circumferential direction. The drive pin  19   b  is passed through a through hole portion  13   d , formed in the rectilinear barrel  13 , and engages with a rectilinear groove portion  12   e  of the moving cam barrel  12 . 
   With the above-described arrangement, during the rotation of the moving cam barrel  12 , the first cam barrel  19  moves in the optical axis direction while rotating around the optical axis along the tapered cam  13   c.    
   In the inner circumferential surface of the first cam barrel  19 , three tapered cams  19   d  are formed so as to extend incliningly with respect to the circumferential direction. These tapered cams  19   d  have the same shape, are positioned at equal intervals, and engages with three follower pins  20   a , provided on an outer circumferential face of a first lens unit holding barrel  20 . An unillustrated rectilinear groove portion is formed in the first lens unit holding barrel  20 . A rotation stopping portion  21   a  of a ring  21  with rotation stopping rod, which is fixed at a rear end portion in the optical axis direction of the first cam barrel  19 , engages with the rectilinear groove portion. Therefore, the rotation of the first lens unit holding barrel  20  around the optical axis is prevented. 
   Thus when the first cam barrel  19  moves in the optical axis direction while rotating around the optical axis, the first lens unit holding barrel  20  moves in the optical axis direction along the cam track of the tapered cam  19   d  while being prevented in rotation around the optical axis by the rotation stopping portion  21   a.    
   The construction of the abovementioned second barrel  18  shall now be described.  FIG. 3  is an exploded perspective view of the second barrel  18 . The arrangement of a focusing unit  30 , which includes the third lens unit holding barrel  15 , and the lens drive mechanism for the focusing operation shall now be described.  FIG. 4  is a perspective view of the focusing unit of the second barrel  18 . 
   Reference Numeral  31  denotes a stepping motor, which is fixed to the second lens unit holding barrel  14 , and the driving force of the stepping motor  31  is transmitted in the order of: gear  31   a →gear  32 →gear  33 →gear  34   a . A screw  34   b , which rotates integrally with the gear  34   a , is fixed to the gear  34   a.    
   Reference Numeral  35  denotes a nut that is fixed unrotatably to the third lens unit holding barrel  15 , and the screw  34   b  is inserted into the nut  35 . 
   Reference Numeral  36  denotes a third cap, which is fixed to the second lens unit holding barrel  14  and supports a guide shaft  37  and the screw  34   b.    
   By the above arrangement, the driving force of the stepping motor  31  is transmitted in the order of: gear  31   a →gear  32 →gear  33 →gear  34   a →screw  34   b , and the third lens unit holding barrel  15  thereby moves in the optical axis direction. 
   Reference Numeral  38  denotes a coil spring which biases the third lens unit holding barrel  15  towards the second lens unit holding barrel  14 , and by the spring force of the coil spring  34 , the play at the screw  34   b  can be repressed and stable driving is enabled. 
   Since it is difficult to perform stable driving of a focusing lens  3  by just the guiding by the guide shaft  37 , an auxiliary guide shaft  14   b  is positioned at a position separated from guide shaft  37  to enable stable driving of the focusing lens  3 . 
   Reference Numeral  39  denotes a photointerrupter (referred to hereinafter as “PI”), which is fixed to the second lens unit holding barrel  14  and is equipped with an unillustrated light emitting element and light receiving element. 
   The third lens unit holding barrel  15  is provided with a light-blocking plate, which blocks light emitted from the light emitting element of the PI  39 , and the position of the third lens unit holding barrel  15  when the light is blocked by the light-blocking plate is deemed to be an initial position. Since the movement amount of the third lens unit holding barrel  15  per step of the step drive of the stepping motor  30  is known in advance, the position of the third lens unit holding barrel  15  can be known by counting the number of steps that have been input. Though unillustrated, electrical wiring connected to the stepping motor  31  and the PI  39  is connected via a flexible circuit board, etc., to a power supply provided at the exterior of the third lens unit holding barrel  15 . 
   The operations of the shutter unit  16  shall now be described. 
     FIG. 5  shows the state wherein shutter blades  46  and  47  are connected to a shutter drive unit  40  (see  FIG. 3 ). In  FIG. 5 , the shutter blades  46  and  47  are in the opened state. 
   Reference Numeral  41  denotes a coil, which is wound around a bobbin, and the magnetic flux that is generated by energization of the coil  41  generates, via a yoke  42 , a rotational force in the direction of arrow A on a magnet  44 , on which an arm  44   a  is formed integrally. 
   A shutter cover  43  has an unillustrated hole portion, which rotatably supports an unillustrated rotating shaft that extends downward in  FIG. 5  from the magnet  44 . The shutter cover  43  holds the coil  41 , the yoke  42 , the magnet  44 , the arm  44   a , and a shutter base plate  45 . 
   The arm  44   a  is inserted in an opening  45   a , formed in the shutter base plate  45 , and the length in the rotation direction of the arm  44   a  at the opening  45   a  is set to be slightly longer than the length in the radial direction of the arm  44   a.    
   Thus by the arm  44   a  contacting the respective end faces of the opening  45   a , the rotational range of the magnet  44  is restricted. 
   The arm  44   a  passes through openings  46   a  and  47   a  formed in the two shutter blades  46  and  47 , and when the rotation operation of the arm  44   a  is started by energization of the coil  41  as mentioned above, the shutter blades  46  and  47  begin to rotate about the openings  46   b  and  47   b , respectively. 
   In this process, the magnet  44  stops at the point at which the magnetic attractive force of the magnet  44  acts on the yoke  42 . This state is thus maintained even after the energization of the coil  41  is terminated. 
   An opening  48   a  is formed in a shutter top plate  48 , and by mounting the shutter top plate  48  after insertion of the arm  44   a  in the opening  48   a , the falling-off of the shutter blades  46  and  47  is prevented. 
   The arrangement and operation of the diaphragm unit  17  shall now be described with reference to  FIGS. 7 and 8 . Here,  FIG. 7  shows the arrangement of the diaphragm unit  17  in the open state, and  FIG. 8  shows the arrangement of the diaphragm unit  17  in the closed state. Cam groove portions  53   a ,  54   a ,  55   a ,  56   a ,  57   a , and  58   a  are respectively formed in diaphragm blades  53 ,  54 ,  55 ,  56 ,  57 , and  58  that make up the diaphragm unit  17 , and cam pins  52   b ,  52   c ,  52   d ,  52   e ,  52   f , and  52   g , formed on the top surface of a diaphragm drive ring  52 , respectively engage with to the cam groove portions  53   a  to  58   a.    
   Protrusions  50   b ,  50   c ,  50   d ,  50   e ,  50   f , and  50   g  are provided on a diaphragm base plate  50 , which is fixed to the object side face of the second lens unit holding barrel  14 . By these protrusions  50   b  to  50   g  engaging respectively with hole portions  53   b ,  54   b ,  55   b ,  56   b ,  57   b , and  58   b , formed in the respective diaphragm blades  53  to  58 , the respective diaphragm blades  53  to  58  are supported rotatably. 
   A stepping motor  51  for driving the diaphragm blades  53  to  58  is fixed to the diaphragm base plate  50 . The output shaft of the stepping motor  51  is passed through a through hole portion  50   a  with fan-like form, which is formed in the diaphragm base plate  50 , and a gear  51   a  is mounted to a front end portion of the output shaft. The gear  51   a  engages with a fan-shaped gear  52   a , which is formed on an outer circumferential portion of the diaphragm drive ring  52 . 
   When the stepping motor  51  is driven, the rotational force of the gear  51   a  is transmitted to the gear  52   a  and the diaphragm drive ring  52  begins a rotational operation along the inner circumference of a recessed portion  50   h  that is formed circularly in the diaphragm base plate  50 . 
   Here, the moving amount in the rotational direction of the gear  52   a  that is formed on the diaphragm drive ring  52  is set to be larger than the through hole portion  50   a , and the rotation range of the diaphragm drive ring  52  is restricted by the contacting of both ends of the gear  52   a  with both end faces of the through hole portion  50   a.    
   When the diaphragm drive ring  52  begins the rotational operation, the respective diaphragm blades  53  to  58  move in accordance with the cam tracks of the cam groove portions  53   a  to  58   a , and the opening area of the diaphragm opening that is formed by these diaphragm blades  53  to  58  changes. 
   The image pickup plane tilt correction mechanism shall now be described. Due to the decentering and tilt of the respective lenses and the decentering and tilt of the lens holding members that make up an optical system, it is difficult to prepare an optical system as designed with respect to a central position. In a case where an optical system deviates from the designed optical center, an object image forming surface and a package surface may not necessarily be perpendicular to the optical axis. 
   The image pickup plane may thus be tilted with respect to the optical axis. Since the image pickup plane and the package surface may not be necessarily parallel but may be tilted with respect to each other, if mounting is performed using a CCD package as a reference, the abovementioned tilt may affect the optical system. 
   Due to these two factors, even if the optical system is in-focus state with respect to the center of the image pickup plane, the focus may be off in opposite directions at two points across the center of the image pickup plane. Thus in order to achieve in-focus on as much of the entirety of the image pickup plane as possible, the tilting of the image plane of the object image formed by the optical system and the tilting of the CCD sensor must be corrected at the same time. 
     FIG. 9  is an exploded perspective view of the image pickup plane tilt correction mechanism. The CCD sensor  6  has an image pickup plane in its interior and is fixed by being adhered onto a CCD holding plate  60 . 
   A pin portion  5   b , which is formed on a CCD base plate  5 , is inserted with minute play in a hole portion  60   a , formed in the CCD holding plate  60 . And the pin portion  5   b  defines the position of the image plane orthogonal to the optical axis. 
   Reference Numeral  63  denotes a rubber that prevents the entry of dirt, etc., onto the CCD plane, and Reference Numeral  64  denotes a CCD mask sheet, which blocks light besides of the image taking light flux. 
   At the face of the CCD base plate  5  that contacts the CCD sensor  6 , hole portions  5   c  are formed at three locations, and in each of the hole portions  5   c , an adjustment spring  61  is inserted in a charged state. 
   The adjustment springs  61  are sandwiched by the CCD base plate  5  and the CCD holding plate  60 , and by receiving the spring force of the charged adjustment springs  61 , the CCD holding plate  60  is pushed away from the CCD base plate  5  in the optical axis direction. 
   Adjustment screws  62   a ,  62   b , and  62   c  are respectively fastened in three corresponding hole portions  5   c  formed in the CCD base plate  5  and press the CCD holding plate  60 , which is biased in the optical axis direction by means of the adjustment springs  61 , toward the CCD base plate  5 . By rotating the three adjustment screws  62   a ,  62   b , and  62   c , the tilt of the image pickup plane with respect to the optical axis can be eliminated. 
   An optimal positioning of parts inside the lens apparatus, for making the lens apparatus in the collapsed state compact in the optical axis direction and radial direction, shall now be described. 
   In the present embodiment, the third lens unit holding barrel  15 , holding the third lens unit  3 , which is positioned at the most image pickup plane side among the first lens unit  1 , second lens unit  2 , and third lens unit  3  that move in the optical axis direction, is incorporated in the second lens unit holding barrel  14 . Since the lens apparatus as a whole can thus move towards the image pickup plane side in the collapsed state, the total length of the lens apparatus in the optical axis direction can be made small. 
   The positional relationship of the stepping motors  31  and  51 , the guide shaft  37 , the auxiliary guide shaft  14   b , and the CCD sensor  6  shall now be described using  FIG. 10 . Here,  FIG. 10  is a view of the second lens unit holding lens barrel  14  as viewed in the optical axis direction, and the image pickup element  6  is projected onto a central portion thereof. 
   In order to make the image taking light flux reach the CCD sensor  6 , it is preferable to position the stepping motors  31  and  51 , the guide shaft  37 , and the auxiliary guide shaft  14   b  at the outer sides of the regions corresponding to an effective image pickup plane  6   a  of the CCD sensor  6 , the optical LPF  7 , and the fourth lens unit  4 . However, since the stepping motors  31  and  51  are elements that are large both in terms of area and volume, depending on the mounting positions, the second lens unit holding barrel  14  may become large in the radial direction. 
   Thus in the present embodiment, the region of the second lens unit holding barrel  14  is divided into the four regions of a mounting region  81 , a mounting region  82 , a mounting region  83 , and a mounting region  84  by radial lines passing from the optical axis  71  through positions corresponding to the four corners of the CCD sensor  6 , and the abovementioned parts are positioned in the respective regions  81  to  84  as follows. 
   That is, the output shaft of the stepping motor  31 , which is the drive source of the third lens unit  3  (focusing lens) is positioned in the mounting region  81 , and the guide shaft  37 , which guides the third lens unit  3  in the optical axis direction, is positioned in the second mounting region  82 . The output shaft of the stepping motor  51 , which is the drive source of the diaphragm blades  53  to  58 , is positioned in the third mounting region  83 , and the auxiliary guide shaft  14   b , which guides the third lens unit  3  in the optical axis direction, is positioned in the fourth mounting region  84 . The gear  31   a  and the gear  32  are positioned in the mounting region  81 , and the gear  33  and the screw  34   a  are positioned in the mounting region  82 . 
   Since the space formed in the second lens unit holding barrel  14  can thus be utilized effectively, the second lens unit holding barrel  14  can be made compact in the radial direction. 
   If the distance from the third lens unit  3  to the guide shaft  37  becomes long, in a case where there is play, the tilting of the third lens unit  3  with respect to the optical axis  71  may become large and the optical performance may become degrade. It is thus preferable to position the guide shaft  37  in the mounting region  82 , which corresponds a long side portion of the CCD sensor  6 , so that the axial distance between the optical axis  71  and the guide shaft  37  will not become large. 
   As shown in  FIG. 10 , the projection of the CCD sensor  6  is rectangular. The mounting regions  82  and  84 , which correspond the long side portions of the CCD sensor  6 , are thus wider in area, that is, in the space for positioning parts than the mounting regions  81  and  83 , which correspond the short side portions of the CCD sensor  6 . 
   As shown in  FIG. 1 , in the collapsed state, the guide shaft  37  and the auxiliary guide shaft  14   b  are positioned outside the region “A” shown by a slanted line, which includes the image pickup element  6 . Since the guide shaft  37  and the auxiliary guide shaft  14   b  can thus be positioned towards the back face side of the camera, the total length of the lens apparatus in the optical axis direction can be made compact. 
   If the guide shaft  37  can be positioned more towards the back face side of the camera, the length of the guide shaft  37  can be made long correspondingly. Tilting of the third lens unit  3  due to play between the third lens unit holding barrel  15  and the shaft can thus be lessened, and high-precision drive of the third lens unit holding barrel  15  with little image blur, can be realized. 
   If the distance between the stepping motor  31  and the guide shaft  37  is too short, the structure of the third lens unit holding barrel  15 , which holds the third lens unit  3  serving as the focusing lens, must be made large in order to avoid interference with the stepping motor  31 . 
   As mentioned above, in the present embodiment, the stepping motor  31  is positioned in the mounting region  81  and the guide shaft  37  is positioned in the mounting region  82 , which is adjacent the mounting region  81 . Since the stepping motor  31  and the guide shaft  37  can thereby be positioned with a predetermined distance in between so that the abovementioned interference will not occur, the third lens unit holding barrel  15  can be made compact. 
   Furthermore, in the region surrounding the guide shaft  37 , the screw  34   b , the coil spring  38 , and mounting members for mounting these parts must be positioned. In the present embodiment, since the guide shaft  37  is positioned in the mounting region  82  of large area, the space inside the second barrel  18  can be utilized effectively and the second lens unit holding barrel  14  can be made compact in the radial direction. 
   Furthermore, in regard to the auxiliary guide shaft  14   b , since the dimensions of the auxiliary guide shaft  14   b  can be set to be smaller than those of the guide shaft  37 , the amount by which it penetrates into the second barrel  18  can be lessened. Thus with this embodiment, the guide shaft  37  and the auxiliary guide shaft  14   b  are positioned respectively in the mounting region  82  and the mounting region  84 , which is symmetrical to the mounting region  82 , and the auxiliary guide shaft  14   b  and the shutter drive unit  40  are positioned so as to overlap in the optical axis direction. The distance between the guide shaft  37  and the auxiliary guide shaft  14   b  can thus be maintained to realize stable focus drive while making the lens apparatus compact in the optical axis direction. 
   In the second barrel  18 , it is preferable that the openings as viewed from the image pickup plane side, which are provided in the prior art, be made as few as possible in order to avoid leakage of light rays. Thus in the present embodiment, the respective parts of the focusing unit  30 , which performs focusing operation and includes the third lens unit holding barrel  15 , are mounted in the second barrel  18 , and portions of the second barrel  18  that must be notched due to the component parts of the focusing unit  30  are thereby eliminated. Since the focusing unit  30  is not mounted to the CCD base plate  5 , the area in which the lens apparatus in housed can be made small as well. 
   While preferred embodiments have been described, it is to be understood that modification and variation of the present invention may be made without departing from the scope of the following claims. 
   “This application claims priority from Japanese Patent Application No. 2003-394267 filed on Nov. 25, 2004, which is hereby incorporated by reference herein.”