Abstract:
A panning stereo endoscope which maintains an up-down orientation as the stereo endoscope pans an operative field, the panning stereo endoscope comprising:
       a shaft having an axis;   first and second optical channels extending along the shaft, each of the first and second optical channels having an off-axis direction of view; and   an actuating mechanism carried by the shaft and adapted to (i) synchronously rotate the first and second optical channels about their respective axes, and (ii) synchronously, inversely piston the first and second optical channels along their respective axes.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATION 
       [0001]    This patent application claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 61/622,368, filed Apr. 10, 2012 by Yuri Kazakevich et al. for 360 DEGREE PANNING STEREO ENDOSCOPE (Attorney&#39;s Docket No. VIKING-8 PROV), which patent application is hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to visualization systems in general, and more particularly to stereoscopic rigid endoscopes. 
       BACKGROUND OF THE INVENTION 
       [0003]    Typically non-stereoscopic rigid endoscopes feature a single optical path extending from the distal end of the endoscope to the proximal end of the endoscope. The optical system typically includes, from distal end to proximal end, (i) an objective lens, (ii) one or more optical relays, and (iii) an ocular portion. The optical system defines the field of view of the endoscope, which typically ranges from about 60° to about 120°, depending on the types of medical procedures that the endoscope is designed to be used for. 
         [0004]    In many circumstances this “instantaneous” field of view is too limited to allow the full operative field to be simultaneously viewed during the medical procedure. As a result, in order to expand the useful field of view, many commercially available endoscopes are designed to have an off-axis direction of view. This off-axis direction of view is achieved by providing a direction-of-view prism in the objective lens portion of the optical system. Typically endoscopes have 30, 45 or 70 degree direction-of-view angles as measured between the direction-of-view axis and the longitudinal axis of the endoscope shaft. Such endoscopes are offered by Karl Storz, Inc., Stryker, Inc., Olympus, Inc. and other manufacturers. 
         [0005]    With an off-axis direction of view endoscope, the user can rotate the endoscope about the longitudinal axis of its shaft and effectively expand the “instantaneous” field of view by twice the angle of view value while the endoscope rotates (or “pans”) about a full 360 degrees. 
         [0006]    In the case of non-stereoscopic endoscopes, the endoscope is typically rotatably coupled to a video camera. In this situation, in order to expand the “instantaneous” field of view, the user simply axially rotates the endoscope relative to the coupled video camera, which is maintained in a relative “up and down” fixed orientation. 
         [0007]    However, with rigid stereoscopic endoscopes, there are typically two parallel optical paths transferring independent optical images to a 3D video camera, where the separate images are received by image sensor(s), converted to electrical signals and further processed in order to be displayed on a 3D viewing device, e.g., a 3D monitor, a 3D head-mounted display or the like. 
         [0008]    Due to the stereoscopic requirement for two separate optical paths, it is not possible to simply axially rotate the stereo endoscope relative to the stereo video camera. Thus, for the user to look right, left, up or down, the entire combination of camera and endoscope rotates, causing the displayed image to also rotate, in much the same manner as if one held a photograph in their hands and rotated the entire image. This situation causes significant inconvenience for the physician performing the endoscopic procedure since it becomes difficult to maintain an up-down orientation and goes against common practice developed over the years for non-stereoscopic endoscopy. 
         [0009]    Thus there is a need for a new 360 degree panning stereo endoscope which maintains an up-down orientation as the stereo endoscope pans an operative field. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention comprises the provision and use of a new 360 degree panning stereo endoscope which maintains an up-down orientation as the stereo endoscope pans an operative field. 
         [0011]    In one preferred form of the invention, there is provided a panning stereo endoscope which maintains an up-down orientation as the stereo endoscope pans an operative field, the panning stereo endoscope comprising: 
         [0012]    a shaft having an axis; 
         [0013]    first and second optical channels extending along the shaft, each of the first and second optical channels having an off-axis direction of view; and 
         [0014]    an actuating mechanism carried by the shaft and adapted to (i) synchronously rotate the first and second optical channels about their respective axes, and (ii) synchronously, inversely piston the first and second optical channels along their respective axes. 
         [0015]    In another preferred form of the invention, there is provided a method for stereoscopically viewing an operative field, the method comprising: 
         [0016]    providing a panning stereo endoscope which maintains an up-down orientation as the stereo endoscope pans an operative field, the panning stereo endoscope comprising:
       a shaft having an axis;   first and second optical channels extending along the shaft, each of the first and second optical channels having an off-axis direction of view; and   an actuating mechanism carried by the shaft and adapted to (i) synchronously rotate the first and second optical channels about their respective axes, and (ii) synchronously, inversely piston the first and second optical channels along their respective axes;       
 
         [0020]    positioning the panning stereo endoscope adjacent to an operative field; and 
         [0021]    viewing the operative field through the panning stereo endoscope and actuating the actuating mechanism. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    These and other objects, features and advantages of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein: 
           [0023]      FIG. 1  is a schematic view of a novel 360 degree panning stereo endoscope formed in accordance with the present invention; 
           [0024]      FIG. 1A  is a schematic view showing further details of the proximal end of the stereo endoscope of  FIG. 1 ; 
           [0025]      FIGS. 2A-2D  are schematic views showing the distal end of the stereo endoscope of  FIG. 1  in four different viewing positions; 
           [0026]      FIGS. 3-6, 7A-7C and 8  are schematic views showing details of the actuating mechanism of the stereo endoscope shown in  FIG. 1 ; and 
           [0027]      FIG. 9  is a schematic view showing an electronic alignment method which may be applied to the stereo endoscope shown in  FIG. 1  (note that in  FIG. 9 , the degree of misalignment has been exaggerated somewhat for clarity of understanding). 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    The present invention comprises the provision and use of a new 360 degree panning stereo endoscope. More particularly, the present invention provides a novel stereo endoscope which allows the user to view up, down, left or right incrementally, in a 360 degree arc, without altering the up-down orientation of the transmitted 3 dimensional image which is being viewed, e.g., on a viewing device such as a 3D monitor, a 3D head-mounted display, etc. 
         [0029]    Looking first at  FIG. 1 , there is shown a stereoscopic endoscope  100  which comprises one preferred embodiment of the present invention. Stereoscopic endoscope  100  comprises two sets of identical moveable viewing optics  1  which protrude from the distal end of the shaft  2  of the stereo endoscope. These viewing optics  1  may be rotated, and advanced and retracted relative to one another, by rotating the knurled actuator  3  as will hereinafter be discussed in further detail. Also shown in  FIG. 1  is the illumination fiber optic input adapter  4  which extends radially from the main body  5  of stereo endoscope  100 . 
         [0030]    Looking next at  FIG. 1A , the two optical output windows  6  are shown on the proximal camera coupling interface  7  which is mounted to body  5  of stereo endoscope  100 . Also shown in  FIG. 1A  is the knurled actuator  3 . Rotating knurled actuator  3  causes the viewing optics  1  (which are preferably in the form of optics tube assemblies) to continuously rotate and piston through a 360 degree panning excursion. This 360 degree panning excursion may be clockwise or counterclockwise. 
         [0031]      FIGS. 2A-2D  show the distal end of stereoscopic endoscope  100  in four different viewing direction positions. More particularly,  FIG. 2A  shows the optics tube assemblies  1  in the “down” looking position. The field of view of each optics tube assembly  1  is approximately seventy degrees radiating from the oblique faces  8  of optics tube assemblies  1 . Illuminating fiber optic bundles  9  are shown above and below optics tube assemblies  1 .  FIG. 2B  shows optics tube assemblies  1  in the “up” looking position. Note how in  FIG. 2B , oblique faces  8  of optics tube assemblies  1  have turned 180 degrees from the position shown in  FIG. 2A .  FIG. 2C  shows optics tube assemblies  1  in the “left” looking position. Note how oblique faces  8  of optics tube assemblies  1  have rotated 90 degrees from the position shown in  FIG. 2A . Note also how optics tube assemblies  1  have pistoned (i.e., one optics tube assembly  1  has moved forward and the other optics tube assembly  1  has moved rearward) from the position shown in  FIG. 2A .  FIG. 2D  shows optics tube assemblies  1  in the “right” looking position. Note how the oblique faces  8  of optics tube assemblies  1  have rotated 90 degrees from the position shown in  FIG. 2A . Note also how optics tube assemblies  1  have pistoned (i.e., one optics tube assembly  1  has moved rearward and the other optics tube assembly  1  has moved forward from the position shown in  FIG. 2A . 
         [0032]      FIG. 3  shows a shortened illustration of the distal end of stereo endoscope  100  and the innermost elements of the actuating mechanism contained within endoscope body  5  (which has been sectioned in this view). More particularly, two sets of identical optical elements are mounted within tubular elements so as to form the aforementioned optics tube assemblies  1 , in a manner similar to that found in single channel rigid endoscopes. These two optics tube assemblies  1  are supported within endoscope body  5  by two alignment decks  10 ,  11 . Two offset spur gears  12 , which may be formed integral with, or mounted to, tubular sleeves  13 , are fixed to the two optics tube assemblies  1 , such that turning spur gears  12  causes optics tube assemblies  1  to turn. The angular positions of the two offset spur gears  12  are precisely matched during the assembly process, and fixed to optics tube assemblies  1  so as to establish and maintain the relationship of the two fields of view  14  provided by the two optics tube assemblies  1 . As also seen in  FIG. 3 , two bearing sleeves  15 , each featuring annular grooves, are also fixed to optics tube assemblies  1 . Bearing sleeves  15  are fixed to optics tube assemblies  1  so as to be equidistant from the distal ends of the optics tube assemblies  1 . 
         [0033]      FIG. 4  shows further elements of the actuating mechanism contained within body  5  of stereoscopic endoscope  100 . More particularly, the actuating elements contained within body  5  of stereo endoscope  100  comprise a ring gear  16  which engages the two spur gears  12 . This gear train (i.e., the two spur gears  12  and ring gear  16 ) is designed to provide two revolutions of spur gears  12  to each revolution of ring gear  16 . Ring gear  16  is secured to a face cam  17 . Face cam  17  is contoured to provide one complete proximal-distal reciprocating excursion of optical tube assemblies  1  for each complete revolution of their respective spur gears  12  as will hereinafter be discussed. In addition, the timing of face cam  17  to the gear train (i.e., to the two spur gears  12  and ring gear  16 ) is such that when the view is “up” ( FIG. 2B ), or “down” ( FIG. 2A ), the timing of face cam  17  will be mid-excursion, and optics tube assemblies  1  will protrude an equal distance from the distal end of the endoscope, as will also hereinafter be discussed. Actuator  3  is captive and rotationally sealed within body  5  of stereo endoscope  100  with only its knurled outer surface protruding from the interior of body  5 . Actuator  3 , when revolved by the user, rotates the cam-ring gear assembly by way of a gear or timing belt connection  18 . In this way, rotation of actuator  3  rotates face cam  17  and ring gear  16 , whereby to rotate and piston optics tube assemblies  1  as will hereinafter be discussed. 
         [0034]      FIG. 5  shows the internal support and alignment elements for the face cam followers  19 ,  20  (which are themselves shown in  FIG. 6 ). In  FIG. 5 , ring gear  16  and face cam  17  have been hidden for the sake of clarity.  FIG. 5  shows the inner cam follower alignment and bearing component  21  which serves as an inner bearing for the inner cam follower  20  ( FIG. 6 ). Inner cam follower alignment and bearing component  21  comprises a transverse slot  22  ( FIG. 5 ) for holding the inner and outer cam follower elements  19 ,  20 , respectively. 
         [0035]    Inner cam follower alignment and bearing component  21  is maintained in position, with its transverse slot  22  appropriately oriented within housing  5 , by two double-shouldered stanchion pins  23  ( FIG. 5 ). 
         [0036]      FIG. 6  shows inner face cam follower  20  and outer face cam follower  19  with their respective points  24  in position on the cam portion  25  of face cam  17 . As may be seen in  FIGS. 7A-7C , each cam follower  19 ,  20  has two follower points  24 , with each follower point  24  being set 180 degrees from the other follower point  24  on a given cam follower. As may also be seen in  FIGS. 7A-7C , the two follower points  24  of one cam follower are offset 90 degrees from the two follower points of the other cam follower. Inner and outer cam followers  19 ,  20  are configured such that their respective alignment tabs  26  ( FIGS. 6 and 7 ) are restrained within the transverse slot  22  of inner cam follower alignment and bearing component  21  such that their respective pairs of follower points  24  are maintained 90 degrees from each other. As a result of the foregoing, when the lobes of cam portion  25  of face cam  17  are revolved one complete rotation, cam followers  19 ,  20  will each make two complete reciprocating movement cycles. More particularly, when face cam  17  is revolved one complete revolution, cam followers  19 ,  20  will have been in the maximum distal position twice and the maximum proximal position twice, and each of cam followers  19 ,  20  will have been aligned, mid-cycle, in the median position twice. 
         [0037]    The distal/proximal cam excursion limits correspond to the  FIG. 2D  (“right”) or  FIG. 2C  (“left”) viewing directions, respectively. The median position of cam followers  19 ,  20  corresponds to  FIG. 2A  (“down”) or  FIG. 2B  (“up”) viewing directions, respectively. 
         [0038]    This reciprocal motion of face cam followers  19 ,  20 , and hence optics tube assemblies  1 , is desirable so that when looking in the “right” or “left” directions, the tip of one optics tube assembly  1  does not partially “eclipse” the field of view of the other optics tube assembly  1 . 
         [0039]      FIGS. 7A-7C  show further details of inner cam follower  20  and outer cam follower  19 . Each of the inner and outer cam followers  20 ,  19  features an alignment tab  26  which rides within the slot  22  of inner cam follower alignment and bearing component  21 . In addition, alignment tab  26  of outer cam follower  19  rides in a slot  28  formed in inner cam follower  20 . Alignment tabs  26  are each configured with two forks  29  which are designed to be captured within the corresponding grooves of bearing sleeves  15  of optics tube assemblies  1 .  FIGS. 7A-7C  also show how each of the cam followers  19 ,  20  comprises a pair of follower points  24  which are disposed 180 degrees from each other. 
         [0040]      FIG. 8  shows the complete actuating (rotary/reciprocation) mechanism contained within endoscope body  5 .  FIG. 8  also shows two return springs  30 ,  31  which maintain cam followers  19 ,  20 , respectively, in contact with the lobes of face cam  17 . Springs  30 ,  31  are sized to match the outside and inside diameters of their respective cam followers  19 ,  20  with sufficient clearances so as not to bind with any surrounding elements during the operating cycle of the stereo endoscope. In addition, springs  30 ,  31  are wound counter to one another for the same reason, i.e., one is left-hand wound and the other is right-hand wound. Springs  30 ,  31  are constrained in proper compression by alignment deck  11  which is fastened to endoscope body  5 . 
         [0041]    On account of the foregoing, it will be appreciated that rotation of actuator  3  by the user causes gear or timing belt connection  18  to rotate face cam  17 . Rotation of face cam  17  causes ring gear  16  to turn spur gears  12 , which in turn causes optical tube assemblies  1  to rotate. At the same time, rotation of face cam  17  causes cam followers  19 ,  20  to move longitudinally, which in turn causes optics tube assemblies  1  to move longitudinally. Thus, rotation of actuator  3  causes optics tube assemblies  1  to simultaneously rotate and piston. Significantly, due to fact that points  24  on cam followers  19 ,  20  are offset at 90 degree intervals, optics tube assemblies  1  piston inversely relative to one another, i.e., as one optics tube assembly  1  pistons forward, the other optics tube assembly  1  pistons rearwardly. Thus it will be seen that rotation of actuator  3  by the user simultaneously causes optics tube assemblies  1  to both rotate and piston, with such positioning being in inverse relation, whereby to provide a 360 degree panning stereo endoscope. 
       Additional Constructions 
       [0042]      FIGS. 1-8  show one preferred embodiment of the present invention, wherein stereo endoscope  100  detachably attaches to a 3D video camera via camera coupling interface  7 . However, if desired, stereo endoscope  100  may be permanently coupled to, and integrated with, a 3D camera. 
         [0043]    Furthermore,  FIGS. 1-8  show a construction employing a manually-driven knurled actuator  3 . Alternatively, the same actuation can be effected by a motorized rotation that can be controlled by a push button or slider switch disposed at the 3D camera, or on a floor pedal, etc. 
         [0044]    In still another form of the invention, electronic alignment methods can be utilized. More particularly, in stereo endoscopy, the alignment between the right and left channel images is important. More particularly, with stereo endoscopy, the right and left channel images must be aligned vertically, horizontally and rotationally. Since the present invention comprises both rotational and axial movement of individual optical channels, keeping proper alignment by opto-mechanical means may be challenging. One way to alleviate this issue is to apply an electronic alignment method. More particularly, such an electronic alignment method may utilize an alignment algorithm which includes the comparison of left and right images (or parts of the left and right images) of a live scene captured by the 3D camera. The left and right images are evaluated for misalignment, and then electronically brought into alignment by image processing means. See  FIG. 9  (note that in  FIG. 9 , the degree of misalignment has been exaggerated somewhat for clarity of understanding). In this respect it should be appreciated that image processing for electronic alignment does not need to be enabled at all times during the medical procedure, which could be too computer intensive and impractical. Rather, inasmuch as misalignment is most likely to result from the panning action, the electronic alignment can be electronically coupled to the actuation mechanism and then enabled for an alignment cycle only after the user changes the direction of view of the stereo endoscope (i.e., by actuating knurled actuator  3 ). 
       Modifications 
       [0045]    While the present invention has been described in terms of certain exemplary preferred embodiments, it will be readily understood and appreciated by those skilled in the art that it is not so limited, and that many additions, deletions and modifications may be made to the preferred embodiments discussed herein without departing from the scope of the present invention.