Abstract:
The present invention is an improved apparatus and method for providing variable-angle endoscopic views in a cavity, such as an internal cavity in a human patient. The apparatus includes an elongated tubular portion with a viewer at its proximal end and a reflector assembly at its distal end. The reflector assembly includes a first reflector and a second reflector, with the second reflector rotationally mounted to permit its rotation about an axis generally aligned with an optical path portion passing from the first reflector to the second reflector. The viewer is preferably a camera rotatably secured to the apparatus. A rotator controls rotation of the second reflector and the camera, so that rotation of the second reflector causes a corresponding rotation of the camera. The assembly thus permits near-spherical viewing of the cavity without requiring substantial movement of the endoscope.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is related to and claims the benefit of U.S. Provisional Application No. 60/076,377, filed Feb. 19, 1998, and U.S. Provisional Application No. 60/081,780, filed Apr. 14, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to viewing systems and, more particularly, to an apparatus and method for providing spherical viewing in a cavity, such as an internal body cavity of a patient. 
     2. Description of the Related Art 
     Minimally invasive surgery (MIS) such as laparoscopic, endoscopic, hysteroscopic, and arthroscopic surgery (referred to hereafter generally as endoscopic surgery), is becoming more widely used because it is often less traumatic to the patient, generally involves less hospitalization time, less discomfort, and less risk to the patient, and is usually less costly than traditional open surgery. 
     The endoscopic surgery is generally preformed using elongate instruments slidably inserted through an opening into a body cavity. If the body cavity is accessible through a naturally occurring body orifice, the instruments may be inserted through that orifice. In cases where the body cavity is otherwise inaccessible, a small incision may be created in the patient to provide access to the area to be treated. A trocar sheath may be inserted in the incision, with the trocar heath configured to permit the slidable insertion and rotation of endoscopes and surgical instruments into the cavity. 
     An endoscope is generally used to view the inside of the body cavity. For example, an endoscope can be used to inspect the condition of the tissue lining a body organ, such as a human uterus. The endoscope can also be used to observe the manipulations being performed by surgical instruments positioned within the body cavity. Most current endoscopes provide a limited and fixed view, so that the surgeon typically must physically reposition the entire endoscope in order to change the endoscopic view within the body cavity, or remove the endoscope entirely and replace it with one having the desired angle of view. Such manipulations and replacements can be undesirable, since they can complicate the surgery and increase the risk of inadvertent damage to body tissue from accidental contact between the tissue and the endoscope. 
     Several previous designs have been proposed to permit individual endoscopes to vary their angles of view without requiring extensive movement of the endoscope. The small sizes of endoscopes, which can be on the order of 3 mm in diameter, place restrictions on such designs, and limit the options available. For example, complicated combinations of optics may be difficult to assemble in the small enclosure provided by the body of many endoscopes. 
     Therefore, those concerned with the development and use of endoscopic surgical systems and the like have long recognized the need for a system which is capable of enabling a surgeon to efficiently view large portions of internal cavities without requiring large manipulations or replacements of endoscopes during a procedure. Accordingly, the present invention fulfills these needs by providing an efficient and effective endoscope apparatus, selectively operable to permit a surgeon to view the majority of the internal area without having to replace or make major movements of the endoscope. 
     SUMMARY OF THE INVENTION 
     Briefly, and in general terms, the present invention provides a new and improved viewing system, apparatus, and method for viewing internal cavities, such as an internal opening in a human body. 
     The present invention provides an endoscope or similar viewing apparatus that permits near-spherical viewing of a cavity, such as an internal enclosure, a crevass, or other generally inaccessible area. The invention permits such viewing without requiring large movements of the endoscope. The apparatus includes a distal portion with distal viewing optics, such as reflectors or cameras, that collect images from the cavity interior. The images are then relayed to the proximal portion of the apparatus, where they can be viewed by a user or relayed to an external display. 
     By moving an internal reflector within the distal portion of the endoscope, the endoscope can vary its angle of view from 0 degrees (i.e., straight ahead from the endoscope distal end) to as much as plus or minus 180 degrees (i.e., looking back toward the proximal portion of the endoscope), depending on the particular design. Rotation of the endoscope distal viewing optics about the endoscope&#39;s longitudinal axis, such as may be accomplished by rotating the entire endoscope about its longitudinal axis, when combined with the previously discussed angle-varying optical procedure, permits the endoscope to achieve near-spherical viewing of the interior of the body cavity, without requiring the endoscope to undertake any movement except a simple rotation about its longitudinal axis. Moreover, where the endoscope is surrounded by or otherwise includes an outer sheath that remains stationary during such rotations, the movement of the interior portions of the endoscope (to permit spherical viewing) can be conducted with the outer sheath remaining stationary, thus preventing any potential damage to tissue that may be in contact with the outer sheath. 
     The invention further provides improved feedback to the user regarding the line of sight along which the system is viewing. The feedback may be provided on a monitor or via directional control mechanisms, such as a rotator knob positioned on the endoscope. 
     These and other features of the invention will become apparent from the following detailed description, when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view of an endoscopic viewing system according to an embodiment of the invention; 
     FIG. 2 is a perspective view of an endoscope according to an embodiment of the invention; 
     FIG. 3 is a cross-sectional side view of the endoscope depicted in FIG. 2, according to an embodiment of the invention; 
     FIG. 4 a  is a perspective view of a proximal portion of an endoscope in accordance with an embodiment of the invention; 
     FIG. 4 b  is a perspective view of a proximal portion of an endoscope in accordance with an embodiment of the invention; 
     FIG. 4 c  is a front view of a video monitor in accordance with an embodiment of the invention; 
     FIG. 5 is a cross-sectional side view of an endoscope, according to an embodiment of the invention; 
     FIG. 6 is a cross-sectional side view of an endoscope, according to an embodiment of the invention; 
     FIG. 7 is a cross-sectional side view of a distal portion of an endoscope, according to an embodiment of the invention; 
     FIG. 8 is a cross-sectional side view of a distal portion of an endoscope, according to an embodiment of the invention; 
     FIG. 9 a  is a perspective view of a distal portion of an endoscope, according to an embodiment of the invention; 
     FIGS. 9 b  and  9   c  are cross-sectional views of the endoscope depicted in FIG. 9 a;    
     FIGS. 10 a  and  10   b  are cross-sectional side views of an endoscope, according to an embodiment of the invention; 
     FIG. 11 is a perspective view of an endoscope, according to an embodiment of the invention; 
     FIG. 12 is a cross-sectional side view of a distal end portion of an endoscope, according to an embodiment of the invention; 
     FIG. 13 is a side view, in partial cross-section, of an endoscope, according to an embodiment of the invention; 
     FIG. 14 is a view of an endoscopic viewing system according to an embodiment of the invention; and 
     FIG. 15 is a perspective view, in partial cross-section, of an endoscope in accordance with an embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings with more particularity, wherein like reference numerals in the separate views indicate like or corresponding elements, there is shown in FIG. 1 a system  10  for endoscopic viewing. The endoscopic system  10  includes an endoscope  12 , a monitor  14  for viewing images received from the endoscope  12 , and an illumination source  16  for providing illumination to the area being viewed by the endoscope  12 . 
     In typical usage, the endoscope  12  is inserted into a cavity  18  or other area to be viewed, such as a human body cavity. The endoscope receives illumination from the illumination source  16 , with the illumination passing through a light-transmitting cable  20 , such as a fiber-optic cable or the like, to the endoscope  12  and into the cavity  18  to illuminate desired portions of the cavity. 
     Although the embodiment depicted in FIG. 1 has the illumination source  16  outside of the endoscope  12 , the illumination source may be positioned on or within the endoscope itself. For example, a small light source, such as an LED or small light bulb, may be positioned on or within the endoscope in a position that permits the light to travel, either directly or through reflectors or fiber-optic cables and the like, to shine on desired portions of the cavity. 
     In FIG. 1, the monitor  14  receives image signals from the endoscope  12 . In the embodiment depicted, the images are transmitted to the monitor  14  via one or more cables  22  passing from the endoscope  12  to the monitor  14 . 
     FIGS. 2 and 3 show in greater detail an embodiment of an endoscope in accordance with the invention. As depicted in FIGS. 2 and 3, the endoscope  12  has a generally tubular shaft  23 , with an enlarged proximal end portion  24  and a distal end portion  26 . In use, the user can grasp the endoscope  12  by its proximal end portion  24  and insert the distal end portion  26  into the cavity  18 . The endoscope  12  can be rotated about its longitudinal axis  27  to provide some control of the viewing direction. 
     The distal end portion  26  includes an optical assembly  28  positioned inside. The optical assembly  28  comprises a first reflector  30  and a second reflector  32 , which in the embodiment depicted are both prisms. The distal end portion  26  includes a window  34  through which the second reflector receives light (and images) from the outside of the endoscope  12 . In the embodiment of FIGS. 2 and 3, the window  34  comprises a clear layer of material that seals the endoscope against fluids and other debris while admitting light for viewing the interior of the body cavity. Such a lens may be formed of various materials, such as plastic, glass, or other materials, depending on the desired application. In other embodiments, the window may simply comprise an unobstructed opening in the distal end portion  26  of the endoscope  12 . 
     The first reflector  30  and second reflector  32  are positioned in the endoscope so as to define an optical path  36  passing from outside of the endoscope  12  (i.e., from inside the body cavity), through the window  34 , to the second reflector  32 , to the first reflector  30 , and then to a CCD camera  38  positioned in the proximal end portion  24  of the endoscope  12 . In the embodiment depicted in FIG. 3, a rod lens  40  transmits light between the first reflector  30  and the camera  38 , so that the optical path  36  passes along the rod lens  40 . The optical path  36  is thus broken into three portions. The first optical path portion  42  passes from the camera  38  to the first reflector  30 ; the second optical path portion  44  passes from the first reflector  30  to the second reflector  32 ; and the third optical path portion  46  passes from the second reflector  32  out through the window  34 . Various lenses  47  are positioned along the optical path  36  to help concentrate and focus images. 
     In the embodiment of FIG. 3, the first reflector  30  is rigidly secured to the interior of the endoscope  12 , while the second reflector  32  is rotatably mounted in the endoscope  12  to permit the second reflector  32  to be rotated about an axis  48  generally aligned with the second optical path portion  44  adjacent to the second reflector  32 . Rotation of the second reflector  32  about its axis  48  does not move or otherwise disrupt the second optical path portion  44 , but that rotation does cause the third optical path portion  46  to “sweep” through viewing angles equivalent to the angular rotation of the second reflector  32 . Thus, the camera  38  is provided with images from the viewing angles swept through by the third optical path portion. For example, a 30 degree rotation of the second reflector  32  will cause the camera to receive images corresponding to a 30 degree sweep of the third optical path. 
     Various techniques may be employed to control rotation of the second reflector. A small actuator motor may be used, such as one positioned at the distal end portion of the endoscope to rotate the second reflector in response to signals received from a user. The second reflector may be rotated by mechanical means, such as a system of actuator motors, pull lines or wires, and/or a gearing system such as that depicted in FIG.  3 . Other control techniques could also be used without departing from the scope of the invention. 
     In order to control the rotation of the second reflector  32 , the embodiment of FIG. 3 includes a gearing system that includes a second reflector gear  50  to which the second reflector  32  is secured. The second reflector gear  50 , which rotates about the second reflector axis  48 , is meshed to a distal gear  52  secured to a gear shaft  54  that passes generally along the length of the endoscope shaft  23 . Secured to the proximal end of the gear shaft  54  is a proximal gear  56 , which in the embodiment depicted is a spur wheel gear. The proximal gear  56  is meshed to a rotator control gear  58 , which in the embodiment shown is a crown gear. The rotator control gear is secured to a rotator control knob  60 . 
     A person skilled in the optical arts will note that rotation of the second reflector  32  about its rotational axis  48  will cause the image received by the camera  38  to rotate in a manner that can be awkward for a user to view and comprehend. To compensate for this effect, the invention in the embodiment of FIG. 3 has the camera  38  rotatably secured to the endoscope shaft  23  to permit its rotation about an axis  62  generally aligned with the first optical path portion  42  adjacent to the camera  38 . Rotation of the camera  38  is controlled to correspond to rotation of the second reflector  32 . In the embodiment depicted in FIG. 3, the camera is secured to a camera gear  64 , which is depicted as a spur wheel gear, having an axis  62  aligned with the first optical path portion  42  adjacent to the camera  38 . The camera gear  64  is meshed to the proximal gear  56  of the gear shaft  54 . In the embodiment shown, the gearing assembly is engineered such that inducing rotation of the second reflector  32  causes an equivalent amount of rotation of the camera  38 . For example, rotating the second reflector  32  by 90 degrees will cause the camera  38  to rotate by 90 degrees, i.e., a one-to-one ratio between the corresponding rotations of the camera  38  and second reflector  32 . Other corresponding rotation ratios between the camera and second reflector may also be used, depending on a particular apparatus. 
     An important issue for endoscopes is the ability of the user to determine in which direction the endoscope is “looking.” Failure to know precisely the direction in which the endoscope is looking can complicate a procedure. Accordingly, it is preferred that the user have a reference indicating the viewing position of the endoscope. 
     The rotator controller of the current invention can serve the function of indicating the viewing angle of the endoscope. In the embodiment depicted in FIGS. 2 and 3, the rotator controller knob  60  is configured to indicate the viewing angle of the endoscope  12 . The rotator knob  60  is rotatably secured to the proximal end portion  24  of the endoscope  12 , with the rotator knob rotational axis  66  parallel to the second reflector rotational axis  48 . Moreover, the gearing assembly between the rotator knob  60  and second reflector  32  is configured such that rotation of the rotator knob  60  causes an equivalent rotation (i.e., a one-to-one corresponding rotation) of the second reflector. For example, a ninety-degree rotation of the rotator knob  60  will cause a ninety-degree rotation of the second reflector  32 . 
     To further assist the user in determining the viewing angle, the rotator knob  60  may include markings or other indicia that show the viewing angle of the endoscope  12 . For example, in the embodiment depicted in FIG. 2, the rotator knob  60  includes a marking  68  indicating the rotational position of the knob  60 , which, in the case where the rotator knob  60  and second reflector  32  have corresponding rotations, also serves to indicate the rotational position of the second reflector  32 , thus depicting the viewing angle of the endoscope  12 . 
     During a surgical procedure, a user may be keeping his or her eyes on the video monitor receiving images from the camera. Thus, the user may not have much opportunity to actually look at the position of the rotator knob. Accordingly, the positional markings on the rotator knob may include surface indicators that can be easily detected by touch, such as variances in surface texture or form. These may include raised, lowered, or roughened surfaces. Thus, the user can know the position of the knob, and hence the viewing angle, by merely touching the knob, without necessarily having to take his or her eyes off of the monitor to actually see the knob. 
     In the embodiment of FIG. 2, the marking  68  is a raised arrow, with the arrow aligned to be parallel with the third optical path portion  46  passing from the second reflector  32  out of the viewing window  34 . Thus, the arrow&#39;s rotational position indicates the actual viewing angle of the endoscope  12 . 
     The indicia may comprise a series of one or more raised portions on the rotator knob  60 , such as one or more raised dots. For example, in the embodiment of FIG. 4 a,  the indicia is a combination of a central raised dot  70  with a series of outer raised dots  72 ,  74 . In the embodiment of FIG. 4 b,  the indicia is a pointer  75  extending from the rotator knob  60 . Like the raised arrow of FIG. 3, the central raised dot  70  and outer raised dots  72 ,  74  of the embodiment in FIG. 4 a  and the pointer  75  of FIG. 4 b  are aligned so as to be parallel to the third optical path portion  46  passing from the second reflector  32  out of the viewing window  34 . Thus, the raised dots  70 ,  72 ,  74  or pointer  75  indicate the line of sight of the endoscope  12 . 
     In a further embodiment, an outside display may indicate the viewing angle of the endoscope, such as where the endoscope provides a signal to a monitor to represent the viewing angle. For example, the rotator knob may include sensors or other devices that provide rotational position signals to a video monitor, with the video monitor providing a numerical, graphical, or other representation of the viewing angle. In the embodiment depicted in FIG. 4 c,  the monitor  14  that provides images of the interior of the cavity on its main screen  76  also depicts a graphical representation  77  of the viewing angle. 
     In the embodiment of FIGS. 1-3, illumination is provided by an external illumination source  16  that provides light through a light-transmitting cable  20 . The light transmitting cable  20  connects to one or more illumination fibers  78  that pass alongside the rod lens  40  and transmit the light to the first reflector  30 , where the light is reflected off of the first reflector  30 , to the second reflector  32 , and then out of the window  34  to the cavity  18 . 
     In the embodiment depicted in FIG. 3, the optical path portions  42 ,  44 ,  46  are generally straight and unobstructed. However, the optical path  36  and its portions  42 ,  44 ,  46  may include additional optical assemblies, such as rod lenses or mirrors, that may bend or otherwise divert the optical path portions  42 ,  44 ,  46  out of the straight paths depicted. For example, in the embodiment depicted in FIG. 5, the first optical path portion  42 , i.e., the portion between the camera  38  and the first reflector  30 , includes a flexible fiber-optic bundle  80  with an objective lens  81  at either end. The flexible fiber-optic bundle  80  permits the shaft  23  of the endoscope  12  to be curved or bent without causing a break in the optical path  36 , as may be necessary for the shaft  23  to pass through tortuous curves in a body passage. Such a feature could permit construction of a rigid but non-straight (e.g., curved) endoscope shaft, or even of a flexible endoscope shaft. 
     FIGS. 6 through 8 depict additional embodiments of the invention, with variations to the optical assemblies. In FIG. 6, a rod lens relay system  82  is positioned along the first optical path portion  42 , with the rod lens system  82  including a series of small rod lenses  84  aligned along the first optical path portion  42 . Various objective lenses  86  are used to concentrate and focus the images along the optical path. 
     The first and second reflectors themselves may be varied within the scope of the invention. For example, the prisms depicted in the various embodiments may be replaced with mirrors or other reflective and/or refractive devices without departing from the scope of the invention. Note that the term “reflector” is, in the terms of this application, considered to encompass any device that diverts the passage of light. Additionally, various optical assemblies, such as filters and/or objective lenses, may be positioned in the optical path to enhance the images received by the camera. For example, FIG. 7 depicts two objective lenses, with a positive objective lens  88  positioned against the first reflector  30  along the first optical path portion  42 , and a negative objective lens  90  positioned against the second reflector  32  along the third optical path portion  46 . FIG. 7 further includes a spacer  92  that may be employed to maintain the spacing between the first reflector  30  and second reflector  32 . The spacer  92  thus serves to assist in securing the reflectors in their desired positions, which can prevent damage to the reflectors if the endoscope is dropped or otherwise roughly handled. The spacer  92  may be formed from a lubricious material that seals the adjacent reflector surfaces from contamination while permitting the second reflector  32  to freely rotate. 
     Returning to FIG. 3, the gear shaft  54  is hollow, defining a channel  94  therein. The channel  94  passes from the outside of the proximal end portion  24  and terminates at an opening  96  in the distal end portion  26  of the endoscope  12 . In the embodiment of FIG. 3, an O-ring  98  is positioned at the distal end of the gear shaft  54  so as to have the channel  94  open to the body cavity while maintaining a seal of other portions of the endoscope  12 . Accordingly, the channel  94  may, depending on its size, be used as an irrigation channel for the introduction and/or removal of irrigating fluids to the cavity. The channel  94  may also serve as an access channel for the introduction of tools, such as surgical tools, to the cavity. 
     In other embodiments of the invention, several channels may be provided in the endoscope, including separate channels for fluid introduction, fluid removal, and instrument introduction. For example, in the embodiment of FIG. 8, three separate channels are provided in the distal end portion  26  of an endoscope  12 . An irrigation channel  100  serves to introduce fluids into the cavity, while a separate fluid removal channel  102  can simultaneously remove fluids. A larger instrument introduction channel  104  permits surgical tools to be introduced into the cavity. 
     Various embodiments of the endoscope distal end portion  26  are within the scope of the invention. In the embodiment depicted in FIG. 3, the window  34  comprises a fixed transparent cover that seals the endoscope, thereby protecting the optical assembly within, including the first reflector  30  and second reflector  32 . FIGS. 9 a,    9   b,  and  9   c  depict the distal end portion  26  of an endoscope similar to that in FIG.  3 . FIG. 9 b  depicts the distal end portion  26  in partial crosssection along the line  9 B— 9 B depicted in FIG. 9 a,  while FIG. 9 c  depicts a partial cross-section along the line  9 C— 9 C. In the embodiment depicted, the second reflector  32  is secured within a rotatable housing  106  that includes a small side opening  108  that allows light to pass between the second reflector  32  and the first reflector  30 . A viewing opening  110  allows light to pass between the second reflector and the window  34 . The window  34  is large enough to cover the entire “sweep” angle through which the second reflector  32  can view, with the window  34  serving to allow light to pass while sealing the entire assembly against outside contamination. Such sealing can make the device easier to sterilize. The housing  106  is rotatably mounted to permit rotation with the second reflector  32  about the second reflector&#39;s rotational axis  48 . 
     In another embodiment, the second reflector is mounted in a rotatable housing that is configured so that it can be positioned on the outside of the endoscope shaft. For example, in the embodiment shown in FIGS. 10 a  and  10   b,  a rotatable housing  112  containing the second reflector  32  can be moved from inside the endoscope shaft  23  to the outside of the endoscope shaft  23 . In the extended position depicted in FIG. 10 a,  the housing  112  is positioned on the outside of the endoscope main shaft  23 . The window  34  is located directly on the rotatable housing  112 , so that the window  34  rotates with the second reflector  32 . By positioning the rotational housing  112  of FIG. 10 a  on an external portion of the endoscope shaft  23 , the rotational housing  112 , and therefore the second reflector  32 , can be rotated 360 degrees about an axis  48  perpendicular to the longitudinal axis  27  of the endoscope  12 . When such a 360 degree rotation of the second reflector  32  is combined with a 360 degree rotation of the endoscope main shaft  23  about its longitudinal axis  27 , complete spherical viewing of the body cavity can be achieved. 
     As depicted in FIG. 10 b,  the housing  112  can be retracted into the endoscope shaft  23 , which may facilitate the endoscope&#39;s insertion into and removal from the cavity being viewed. Various devices can be used to retract and deploy the housing  112 . In the embodiment depicted in FIG. 10 b,  the housing  112  is biased toward the retracted position by a spring  114  that urges the gear shaft  54 , and hence the housing  112 , away from an opening  116  in the endoscope shaft  23 . Extending the housing  112  out of the shaft  23  is achieved by an electromagnet  118  that, when activated by sufficient voltage to overcome the resistance of the spring  114 , urges an opposite movement of the gear shaft  54  so as to cause the housing  112  to assume the extended position depicted in FIG. 10 a.  Because the spring  114  is constantly urging the housing  112  to the retracted position of FIG. 10 b,  an accidental or intentional interruption of power to the electromagnet  118  will cause the housing  112  to retract. Note that, in the embodiment of FIGS. 10 a  and  10   b,  the spring  114  and electromagnet  118  are secured to the shaft so as to permit the gear shaft  54  to freely rotate about its axis. In the embodiment depicted, the retracted housing  112  is sized to assist, in both the retracted and expanded positions, in maintaining a seal about the opening  116  in the endoscope shaft  23 , thereby preventing the admission of contaminants into the endoscope shaft  23 . 
     Also in FIGS. 10 a  and  10   b,  the fiber-optic bundle  80  of the first optical path portion  42 , and the illumination line  78 , are positioned within the hollow gear shaft  54 . Although the alignment of the gear shaft  54  and fiber-optic bundle  80  appears to be offset in FIGS  10   a  and  10   b  between the endoscope distal portion  26  and the endoscope proximal portion  24 , they are in fact aligned. The apparent misalignment is caused by the “break” in the each figure between the ends of the endoscope, and is further exaggerated by the endoscope length being much larger as compared to the endoscope width. 
     The fiber-optic bundle  80  and illumination line  78  may be configured to remain stationary when the hollow gear shaft  54  rotates around them. As an alternative approach, a fiber-optic bundle such as that depicted in FIGS. 10 a  and  10   b can be secured at its distal end  120  so that the distal end  120  remains stationary when the control knob  60  and gear shaft  54  are rotated, but the fiber-optic bundle proximal end  122  is secured or geared such that it rotates with the gear shaft  54  and/or control knob  60  so that the proximal end  122  of the fiber-optic bundle  80  will rotate by an amount corresponding to the rotation of the second reflector  32 . This “twisting” of the fiber-optic bundle will result in the image at the proximal end  122  of the bundle  80  being rotated. Thus, there is no need to rotate a camera to compensate for rotation of the second reflector. Such an assembly can be used with a remote camera that may receive optical signals from the endoscope via a fiber-optic line. Such an assembly could also be used without any camera, with a user using an eyepiece to “directly” view the image supplied by the fiber-optic bundle  80  and other optics present. 
     In order to keep a viewing window formed of solid material (as opposed to an open window) clean of debris, an irrigation channel can be positioned so as to provide a fluid flow that passes over the window. For example, in FIG. 11, which is similar to the embodiment of FIG. 3, an irrigation channel opening  124  is positioned so that the fluid flow passes along the surface of the window  34 , thereby washing debris off of the window  34 . In FIG. 12, which is similar to the embodiment of FIG. 10, the irrigation channel opening  124  is positioned so that, when the housing  112  is rotated to a certain position, an irrigation flow passes over the window  34 . Thus, a user can clean the window  34  by rotating the housing  112  into a position adjacent the irrigation channel  124 . 
     Other embodiments (such as FIG. 1) of the invention have a monitor positioned apart from the endoscope, but a monitor may be positioned on the endoscope itself. For example, in the embodiment depicted in FIG. 13, the endoscope  12  includes a monitor  14  secured to the proximal portion of the endoscope  12 . The monitor  14  is relatively small, and is positioned to generally mimic the position of an eyepiece on a conventional endoscope. Thus, a user who is accustomed to conventional endoscopes equipped with eyepieces may be more comfortable using the endoscope-mounted monitor  14  than he or she would be viewing a surgical procedure on a large monitor separate from the endoscope. The endoscope-mounted monitor  14  may thus be used in lieu of, or in addition to, an external monitor such as the one depicted in FIG.  1 . 
     FIG. 14 depicts another embodiment of the invention, wherein an endoscopic system  126  includes an endoscope  12  with a camera  38  rigidly mounted to the endoscope  12 , as opposed to the rotational mounting depicted in other embodiments. To correct for undesirable viewing problems caused by rotation of the second reflector, the system  126  of FIG. 14 includes a processor  128  that receives the image signals from the camera  38 , and then processes the signals to compensate for the rotation of the second reflector. The processing of the signals includes: (1) receiving a position signal from the endoscope  12  indicating the rotational position of the second reflector; (2) “rotating” the image from the camera  38  by an angle corresponding to the angle of rotation of the second reflector; and (3) providing a rotated image to the monitor  14 , with the rotation of the image corresponding to the rotation of the second reflector. Such a rotation of the image can be achieved through relatively simple processing. 
     FIG. 15 depicts a further embodiment, wherein the optical lens assembly is replaced with a small camera  130 , such as a CCD camera, which is itself positioned at the distal end portion  26  of the endoscope  12 . The camera  130 , which in the embodiment depicted has an objective lens  132  positioned at its face, provides a view about a line of sight  134 . The camera  130  is mounted in the endoscope  12  so as to permit the camera  130  to be rotated to move its line of sight  134  to almost any desired viewing angle. In the embodiment depicted, the camera  130  is secured to a first actuator device  136 , which may include an actuator motor, configured to rotate the camera  130  about an axis perpendicular to the longitudinal axis  27  of the endoscope  12 . The first actuator device  136  is itself mounted on a second actuator device  138  configured to rotate about an axis generally aligned with the longitudinal axis  27  of the endoscope  12 . The first actuator device  136  and second actuator device  138  are controlled by a control device, depicted as a control knob  60  secured to a rotating band  140 , positioned at the proximal end portion  24  of the endoscope  12 , which provides control signals through control lines  144  passing through the endoscope  12 . 
     In the embodiment of FIG. 15, the control knob  60  is secured to the rotatable band  140  passing around the distal end portion  26  of the endoscope  12 . The control knob  60  includes indicia, in this case a raised arrow  142 , that indicates the line of sight  134  of the camera  130 . The control knob  60  provides signals to the first actuator device  136 , so that rotation of the control knob  60  causes a corresponding rotation of the first actuator device  136  (and hence a rotation of the camera  130 ) about an axis perpendicular to the longitudinal axis  27  of the endoscope. For example, for a one-to-one (i.e., equivalent) correspondence, a 90 degree rotation of the control knob  60  will cause a 90 degree rotation of the first actuator device  136  and camera  130 . Similarly, the rotatable band  140  provides signals to the second actuator device  138 , so rotation of the rotatable band  140  about the longitudinal axis  27  of the endoscope  12  causes a corresponding rotation of the second actuator device  138 , thereby causing rotation of the camera  130  about the longitudinal axis  27  of the endoscope  12 . By having the physical position of the knob  60  and its marking  142  aligned with the line of sight  134  of the camera  130 , a user can easily determine and understand the angle of the camera line of sight  134 . 
     Other assemblies may also be used to control the position of the camera line of sight  134  in embodiments having the camera positioned in the distal end portion  26 . For example, a system of gears, such as that depicted in the embodiment of FIG. 3 of this application, could be used to control the camera line of sight. A system of wires and pulleys might also be used. 
     Although preferred and alternative embodiments of the invention have been described and illustrated, the invention is susceptible to modifications and adaptations within the ability of those skilled in the art and without the exercise of inventive faculty. Thus, it should be understood that various changes in form, detail, and usage of the present invention may be made without departing from the spirit and scope of the invention. For example, while the specific embodiments set forth herein are directed toward endoscopes for use in surgical procedures, it is apparent that the apparatus would have use in various other applications where viewing of remote areas is desired. Accordingly, it is not intended that the invention be limited, except as by the appended claims.