Abstract:
An actuator apparatus provided in an image pickup apparatus and an endoscopic apparatus according to the invention includes a mobile unit that is movable forward and backward, an urging unit that urges the mobile unit in one direction, and a wire fixed to the mobile unit. In this case, both ends of the wire are connected to a driving source that moves the mobile unit in the other direction against the urging force by the urging unit. According to the invention, the implementation of a small actuator apparatus in a simple structure allows the reduction of the diameter of the image pickup apparatus and endoscopic apparatus including the actuator.

Description:
[0001]    This application claims benefit of Japanese Application No. 2007-031159 filed on Feb. 9, 2007, the contents of which are incorporated by this reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an actuator apparatus, image pickup apparatus, and endoscopic apparatus having a small diameter. 
         [0004]    2. Description of the Related Art 
         [0005]    As well known, an endoscopic apparatus has been widely used for observing and/or treating the inside of (a body cavity of) a human body or for examining and/repairing within industrial plant facilities. In recent years, an image pickup apparatus may be used which has an observation optical system to be moved in the optical axis direction for shooting to switch to a focus function and zooming/tele function to a subject. 
         [0006]    This kind of technology that adjusts a lens frame for a focusing function, for example, in an image pickup apparatus is disclosed in Japanese Unexamined Patent Application Publication No. 5-341209. The patent document discloses a technology that moves a lens frame by fixing one end of a coil spring formed by a shape memory alloys (which will be called “SMA” hereinafter) wire to a projection integrated to the lens frame to which a lens is attached and passing or not passing a current to the coil spring through two lead lines connected thereto. 
       SUMMARY OF THE INVENTION 
       [0007]    According to an aspect of the present invention, there is provided an actuator apparatus including a mobile unit that is movable forward or backward, an urging unit that urges the mobile unit in one direction, and a wire fixed to the mobile unit, wherein both ends of the wire are connected to a driving source that moves the mobile unit in the other direction against the urging force by the urging unit. 
         [0008]    According to another aspect of the present invention, there is provided an image pickup apparatus including the actuator apparatus, wherein the mobile unit has an optical lens, and the wire is connected so as to fold back at a latching member connecting to the mobile unit. 
         [0009]    According to another aspect of the present invention, there is provided an endoscopic apparatus including the image pickup apparatus, wherein a rigid portion, a bending portion and a flexible portion are connected sequentially from the distal end, and one and the other ends of the wire are connected to the cable at the front and the rear portion of the bending portion, respectively. 
         [0010]    The above and other objects, features and advantages of the invention will become more clearly understood from the following description referring to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a configuration diagram of an image pickup apparatus for an electronic endoscope according to a first embodiment; 
           [0012]      FIG. 2  is a section diagram taken by the line II-II in  FIG. 3 ; 
           [0013]      FIG. 3  is a front view of the distal end portion of an endoscope; 
           [0014]      FIG. 4  is a section diagram taken by the line IV-IV in  FIG. 1 ; 
           [0015]      FIG. 5  is an enlarged diagram of the part V in  FIG. 4 ; 
           [0016]      FIG. 6  is a configuration diagram of an insulating ball; 
           [0017]      FIG. 7  is a configuration diagram of another insulating ball; 
           [0018]      FIG. 8  is an enlarged diagram of a part where a lens moves; 
           [0019]      FIG. 9  is a section diagram corresponding to  FIG. 4  according to a second embodiment; 
           [0020]      FIG. 10  is a section diagram corresponding to  FIG. 4  according to a third embodiment; 
           [0021]      FIG. 11  is a section diagram corresponding to  FIG. 4  according to a fourth embodiment; and 
           [0022]      FIG. 12  is a section diagram corresponding to  FIG. 4  according to a fifth embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    The present invention will be described based on embodiments with reference to drawings below. 
       First Embodiment 
       [0024]    First of all, the present invention will be described with reference to  FIGS. 1 to 8 .  FIGS. 1 to 8  relate to a first embodiment of the present invention, and  FIG. 1  is a configuration diagram of an image pickup apparatus for an electronic endoscope,  FIG. 2  is a section diagram taken by the line II-II in  FIG. 3 ,  FIG. 3  is a front view of the distal end portion of an endoscope,  FIG. 4  is a section diagram taken by the line IV-IV in  FIG. 1 ,  FIG. 5  is an enlarged diagram of the part V in  FIG. 4 ,  FIG. 6  is a configuration diagram of an insulating ball,  FIG. 7  is a configuration diagram of another insulating ball, and  FIG. 8  is an enlarged diagram of a part where a lens moves. 
         [0025]    This embodiment describes an image pickup unit  1  included in an image pickup apparatus to be used for an endoscope, in which an internal lens moves forward and backward as shown in  FIG. 1  for a focus function or zooming/tele function. In the image pickup unit  1 , an actuator  2  is provided on a mobile lens frame  4 . A mobile lens  6  is attached to the mobile lens frame  4 . The mobile lens  6  is an optical lens that moves forward and backward. The actuator  2  moves the mobile lens frame  4  forward and backward. In order to attach the actuator  2  included in an actuator apparatus to the mobile lens frame  4 , a long cylindrical connecting pole  5  which is connected to a latching member for latching a wire, which will be described later is provided within the image pickup unit  1 . 
         [0026]    The mobile lens frame  4  is provided movable forward and backward along a shooting optical axis within a lens frame holding a front lens group and a substantially ring-shaped fixed lens frame  3  holding a lens group placed at the back. The outer circumferential part of the fixed lens frame  3  has a longitudinal groove that allows movement of the connecting pole  5 . A movement butt ring  7  is fitted into the groove. The movement butt ring  7  is used for controlling the forward/backward movement of the connecting pole  5  and the mobile lens frame  4 . 
         [0027]    Next, the configuration of the actuator  2  attached to the image pickup unit  1  will be described. 
         [0028]    A shape memory alloys (which will be called “SMA” hereinafter) wire  8  is fixed to the actuator  2  through the groove on the connecting pole  5  and folds back at the position of the connecting pole  5 . The SMA wire  8  is a wire several tens microns in diameter, which contains SMA that contracts if heated and expands if cooled. 
         [0029]    A first insulating tube  9  is externally inserted to the SMA wire  8  up to a middle part from the proximal end to the distal end. The first insulating tube  9  is partially inserted and fixed to the proximal end portion of a guide pipe  22 . 
         [0030]    A pressure spring  10  is held through the guide pipe  22  between the first insulating tube  9  and the connecting pole  5 . The pressure spring  10  contains an elastic body, which is an urging unit, and presses the connecting pole  5  forward. 
         [0031]    The guide pipe  22  has a guide groove  23 , and the connecting pole  5  moves forward/backward within a notch in the guide groove  23 . 
         [0032]    The ends of the SMA wire  8  are caulked by a first caulking portion  16 , which is a metallic ring in a tube shape. A first cable  17  is attached to the first caulking portion  16  by soldering. The first cable  17  applies current to the SMA wire  8 . The circumference of the connecting part, not shown, between the first caulking portion  16  and the first cable  17  is reinforced and bonded by an adhesive, for example. 
         [0033]    The first caulking portion  16  is attached at the distal end part of a flexible tube portion  230  beyond a bending portion  220  (at the position where the angle is manipulated by a bending piece  32 ) of an endoscope  200 , as shown in  FIG. 2 . 
         [0034]    The image pickup unit  1  is fixed to a rigid portion  210  of the endoscope  200 . As shown in  FIG. 3 , the distal end surface of the rigid portion  210  of the endoscope  200  has an observation window  201 , a cleaning nozzle  202 , two illumination windows  201  and  203  and an opening  205  at predetermined positions. The observation window  201  is the distal end of the image pickup unit  1 . The cleaning nozzle  202  cleans the observation window  201  by spraying fluid. The opening  205  is an opening of a channel through which a treatment instrument is inserted. 
         [0035]    Referring back to  FIGS. 1 and 2 , a first insulating tube  9  and a GND cable  27  are threaded through and fixed to a ring-shaped anchor  19 . Then, a protective tube  20  is attached to the first insulating tube  9  and the GND cable  27  for covering the anchor  19 , the first insulating tube  9  and a mobile insulating tube  26 . The distal end side of the protective tube  20  is fixed to the first insulating tube  9  by tying with a string  21  such as a gut. 
         [0036]    Next, a method for fixing the SMA wire  8  and the connecting pole  5  will be described. 
         [0037]    The distal end part of the SMA wire  8  extends through a narrow second insulating tube  11 , as shown in  FIG. 5 . In order to prevent the conduction between the SMA wire  8  and the connecting pole  5 , the second insulating tube  11  is bonded and fixed to and through the connecting pole  5  (refer to  FIG. 8 ). 
         [0038]    The SMA wire  8  is wound once about and through an insulating ring  12 , which is a latching member including a narrow fixing insulating tube (refer to  FIG. 6 ). The insulating ring  12  is placed within an insulating ball  30 , which is a ball formed by an adhesive. The insulating ball  30  is latched with and connected and fixed to the connecting pole  5  with an adhesive or the like. 
         [0039]    As shown in  FIG. 5 , a GND SMA wire  28 , which extends beyond the insulating ball  30  of the SMA wire  8  folds back through the inside of the mobile insulating tube  26  and a third insulating tube  25 . In other words, the SMA wire  8  is configured to keep the electric insulation by the first insulating tube  9 , the second insulating tube  11 , the insulating ring  12 , an insulating cap  13 , an insulating pipe  15 , the mobile insulating tube  26 , the third insulating tube  25  and a second thermal contraction tube  24 . 
         [0040]    An end of the GND (ground) SMA wire  28  is caulked by a second caulking portion  29 , as shown in  FIG. 4 . A GND (ground) cable  27  is soldered to a side of the second caulking portion  29 . 
         [0041]    Here, as described above, in the actuator  2  of the image pickup unit  1  of the present embodiment, the connecting position by soldering between the first caulking portion  16  fixed to the end of the SMA wire  8  and the lead line of the first cable  17  and the connecting position by soldering between the second caulking portion  29  fixed to the end of the GND SMA wire  28  and the lead line of the GND cable  27  are spaced apart by a predetermined distance in the longitudinal direction. 
         [0042]    In other words, as shown in  FIG. 2 , the connecting position by soldering between the first caulking portion  16  fixed to the end of the SMA wire  8  and th lead line of the first cable  17  is different by a predetermined separating distance toward the proximal end from the connecting position by soldering between the second caulking portion  29  fixed to the end of the GND SMA wire  28  and the lead line of the GND cable  27 . 
         [0043]    More specifically, according to the present embodiment, the connecting position by soldering between the second caulking portion  29  fixed to the end of the GND SMA wire  28  and the lead line of the GND cable  27  exists around the boundary between the rigid portion  210  and the bending portion  220  of the endoscope  200 . The connecting position by soldering between the first caulking portion  16  fixed to the end of the SMA wire  8  and the lead line of the first cable  17  exists near the distal end of the flexible tube portion  230  of the endoscope  200 . 
         [0044]    The dimensions are defined so as to satisfy t 1 &lt;10α (refer to  FIG. 6 ) where the diameter of the SMA wire  8  is α, and the length in the axial direction of the insulating ring  12  is t 1 . 
         [0045]    Like the length t 1  in  FIG. 6 , the length in the axial direction of the insulating ring  12  is sufficiently shorter than the diameter of the SMA wire  8 , the insulating ring  12  is pulled by the SMA wire  8  and inclines. Thus, the SMA wire  8  passes through substantially the center of the insulating ball  30 . Therefore, the insulating ball  30  is prevented from being caught by the guide pipe  22 . 
         [0046]    On the other hand, in a case where the dimensions are defined so as to satisfy t 2 &gt;10α (longer than 10 times) where the diameter of the SMA wire  8  is α, and the length of the insulating ring  12  is t 2  and if the length of the insulating ring  12  is longer than the diameter of the SMA wire  8 , as shown in  FIG. 7 , the insulating ring  12  cannot rotate and is pressed by the repulsion of the SMA wire  8 . Thus, the SMA wire  8  passes by the end of the insulating ball  30 ′ (y 1 &gt;y 2 ). In this configuration, the SMA wire  8  causes offset with respect to the insulating ball  30 , and the insulating ball  30  is caught by the guide pipe  22 , which may cause poor sliding of the SMA wire  8 . 
         [0047]    Therefore, according to the present embodiment, the length t 1  in the axial direction of the insulating ring  12  is defined to be shorter than 10 times of the diameter a of the SMA wire  8 . 
         [0048]    Next, an operation by the image pickup unit  1  of the present embodiment with the configuration described above will be described. 
         [0049]    In order to drive the actuator  2  of the image pickup unit  1  by the endoscope  200  for a focus function or a zooming/tele function to a subject, current flows from a power supply included in a driving source, not shown, to the cable  17  based on a predetermined operation by an operating section, not shown, of the endoscope. Then, the current sequentially flows to the cable  17 , the SMA wire  8 , the GND SMA wire  28  and the GND cable  27 , and the SMA wire  8  and the GND SMA wire  28  generate heat and contract. 
         [0050]    Then, the mobile insulating tube  26  is pulled to move until the state of a mobile insulating tube  26 ′, which is indicated by the broken line, is obtained. Here, the insulating ball  30  latched in front of the connecting pole  5  is pulled by the SMA wire  8  against the urging force of the pressure spring  10 . Then, the mobile lens frame  4  is interlocked with the connecting pole  5  in the movement toward the proximal end and moves to the position of the mobile lens frame  14 , which is indicated by the broken line. 
         [0051]    Since the SMA wire  8  and the GND SMA wire  28  exhibit an identical contracting behavior, an undue load is not imposed on the distal end parts of the SMA wire  8  and GND SMA wire  28 , which allows a stable behavior thereby. 
         [0052]    Here, when the current flow to the cable  17  is stopped, the SMA wire  8  and GND SMA wire  28  are naturally cooled and return to the original lengths. At that time, the force by the pressure spring  10  pushes and moves the connecting pole  5  forward. With this, the mobile lens frame  14  moved toward the proximal end moves from the position indicated by the broken line to the position of the mobile lens frame  4 . 
         [0053]    In this way, according to the present embodiment, the SMA wire  8  folds back at the distal end, and the connecting position between the lead line of the cable  17  and the SMA wire  8  is spaced apart in the longitudinal axis direction to the proximal end side from the connecting position between the lead line of the GND cable  27  and the GND SMA wire  28 . In addition, the SMA wire  8  is connected at the fine outside shape of the rear part of the image pickup unit  1 . Therefore, the diameter of the rigid portion  210 , which is the distal end portion of the endoscope  200 , can be reduced. 
         [0054]    Furthermore, the diameter of the distal end portion of the endoscope  200  can be reduced by not providing the connecting position between the lead line of the cable  17  and the SMA wire  8  at the distal end of the SMA wire  8 . Since the SMA wire  8  has bad bondability, or so-called spreadability, the diameter being as narrow as several tens microns, the first caulking portion  16  is connected to the SMA wire  8 , which prevents an increase of the size of the connecting part by soldering with the lead line of the cable  17 . 
       Second Embodiment 
       [0055]    Next, with reference to  FIG. 9 , an actuator  2  of an image pickup unit  1  of a second embodiment will be described. The same reference numerals are given to the same components as those of the first embodiment, and the description thereon will be omitted. Only differences therebetween will be described.  FIG. 9  relates to the second embodiment of the invention and is a section diagram corresponding to  FIG. 4  of the first embodiment. 
         [0056]    According to the present embodiment, instead of the GND SMA wire  28  in the first embodiment, a wire  51  is used which contains a conductive material such as stainless and steel. The proximal end of the wire  51  is caulked to the second caulking portion  29  and is electrically connected to the GND cable  27  by soldering. On the other hand, the other end of the wire  51  on the distal end side is caught and folds back at the insulating ring  12  (refer to  FIG. 6 ), like the SMA wire  8  of the first embodiment, and the wire  51  extends through the insulating tube  11 . The wire  51  and the SMA wire  8  are caulked and connected by a metallic wire caulking portion  52 . 
         [0057]    According to the present embodiment, the wire  51  and the SMA wire  8  are connected by the wire caulking portion  52  to be electrically connected within the guide pipe  22 . 
         [0058]    Also in this configuration, the current applied to the cable  17  subsequently flows into the first caulking portion  16 , the SMA wire  8 , the wire caulking portion  52 , the wire  51 , the second caulking portion  29  and the GND cable  27 . Thus, according to the present embodiment, the heat generation or cooling to the normal temperature of the SMA wire  8  causes the mobile lens frame  4  interlocked with the connecting pole  5 , to be pulled by the SMA wire  8  against the urging force of the pressure spring  10  and move toward the proximal end or to be pushed to move forward by the force of the pressure spring  10 . 
         [0059]    Therefore, like the first embodiment, the actuator  2  of the image pickup unit  1  can be driven by the endoscope  200  for a focus function or zooming/tele function to a subject. 
         [0060]    The configuration of the actuator  2  of the present embodiment can also provide the same operational effects as those of the first embodiment as described above. 
       Third Embodiment 
       [0061]    Next, with reference to  FIG. 10 , an actuator  2  of an image pickup unit  1  of a third embodiment will be described. The same reference numerals are given to the same components as those of the first and second embodiments, and the description thereon will be omitted. Only differences therebetween will be described.  FIG. 10  relates to the third embodiment of the invention and is a section diagram corresponding to  FIG. 4  of the first embodiment. 
         [0062]    The actuator  2  of the present embodiment has a configuration in which an SMA wire  54  is connected to the GND side of the wire  51  of the second embodiment. The SMA wire  54  of the present embodiment may be replaced by the GND SMA wire  28  of the first embodiment. 
         [0063]    One end on the proximal end of the SMA wire  54  is caulked to the second caulking portion  29  and is electrically connected to the GND cable  27 . The other end on the distal end of the SMA wire  54  is caulked and connected with the wire  51  by a metallic caulking portion  53 . The other configuration is the same as that of the second embodiment. 
         [0064]    Also in this configuration, the current applied to the cable  17  sequentially flows into the first caulking portion  16 , the SMA wire  8 , the wire caulking portion  52 , the wire  51 , the caulking portion  53 , the SMA wire  54 , the second caulking portion  29  and the GND cable  27 . 
         [0065]    Thus, according to the present embodiment, the heat generation or cooling to the normal temperature of the SMA wires  8  and  54  causes the mobile lens frame  4  interlocked with the connecting pole  5 , to be pulled by the SMA wire  8 ,  54  against the urging force of the pressure spring  10  and move toward the proximal end or to be pushed to move forward by the force of the pressure spring  10 . 
         [0066]    Therefore, like the first embodiment, the actuator  2  of the image pickup unit  1  can be driven by the endoscope  200  for a focus function or zooming/tele function to a subject. 
         [0067]    The configuration of the actuator  2  of the present embodiment can also provide the same operational effects as those of the first and second embodiments as described above. 
       Fourth Embodiment 
       [0068]    Next, with reference to  FIG. 11 , an actuator  2  of an image pickup unit  1  of a fourth embodiment will be described. Also in the following description, the same reference numerals are given to the same components as those of the first to third embodiments, and the description thereon will be omitted. Only differences therebetween will be described.  FIG. 11  relates to the fourth embodiment of the invention and is a section diagram corresponding to  FIG. 4  of the first embodiment. 
         [0069]    According to the present embodiment, the insulating tube  9  may be a multilumen tube having two wire through holes, and both ends of the SMA wire  8  extend through the through holes from the distal end side. 
         [0070]    More specifically, the SMA wire  8  folds back at the insulating ring  12  to have a loop shape on the distal end side of the guide pipe  22  fixed to the insulating tube  9 . Then, both ends of the SMA wire  8  are caulked by the caulking portions  16  and  29  at the same position (distance) from the distal end. The positions of the caulking portions  16  and  29  are connecting positions near the distal end of the flexible tube  230  of the endoscope  200  according to the first embodiment. 
         [0071]    Both wires of the folded SMA wire  8  are fixed through the insulating tube  9  so as to pull the insulating ring  12  against the urging force of the pressure spring  10  by the heat generation by the passage of current. 
         [0072]    The actuator  2  of the present embodiment having the configuration as described above can pull the insulating ring  12  with an amount of force substantially twice as that of the first embodiment. As a result, the actuator  2  can move the mobile lens frame  4  forward/backward instantly (in a short period of time) for a focus function or zooming/tele function to a subject. 
       Fifth Embodiment 
       [0073]    Next, with reference to  FIG. 12 , an actuator  2  of an image pickup unit  1  of a fifth embodiment will be described. Also in the following description, the same reference numerals are given to the same components as those of the first to fourth embodiments, and the description thereon will be omitted. Only differences therebetween will be described.  FIG. 12  relates to the fifth embodiment of the invention and is a section diagram corresponding to  FIG. 4  of the first embodiment. 
         [0074]    In the actuator  2  of the present embodiment, the insulating ring  12  is pulled/loosened by a wire  55  simply of stainless or steel, for example, without using an SMA wire. 
         [0075]    Both ends of the wire  55  of the present embodiment extend through the insulating tube  9  having two wire through holes, like the SMA wire  8  of the fourth embodiment, and the wire  55  folds back at the insulating ring  12  on the distal end side of the guide pipe  22 . Both ends of the wire  55  are fixed to a motor head  56  attached to a motor (not shown) constituting a driving source. 
         [0076]    In the actuator  2  having the configuration, the motor head  56  is driven to rotate by the motor, and the wire  55  is wound about the motor head  56 . Thus, the insulating ring  12  moves backward against the urging force of the pressure spring  10 . The reverse rotation of the motor returns the wire  55  wound about the motor head  56 , and the insulating ring  12  moves forward by the urging force of the pressure spring  10 . 
         [0077]    The actuator  2  of the present embodiment having the configuration as described above can move the mobile lens frame  4  forward/backward instantly (in a short period of time) for a focus function or zooming/tele function to a subject, like the effects of the fourth embodiment described above. The actuator  2  is configured to prevent an increase in temperature by the heat generation of an SMA wire since an SMA wire is not used. 
         [0078]    Having described the aspect in which the actuator  2  is attached to the mobile lens frame  4  to move a lens according to the embodiments above, the subject to be moved is not limited to a lens. The present invention is also applicable to the transportation of parts in a manufacturing line in a factory, for example. 
         [0079]    Based on the descriptions above, according to the invention, the size of the actuator apparatus can be reduced, which can reduce the sizes and diameters of the distal end portions of an image pickup apparatus and endoscope. 
         [0080]    Having described the preferred embodiments of the invention referring to the accompanying drawings, it should be understood that the present invention is not limited to those precise embodiments and various changes and modifications thereof could be made by one skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims.