Patent Publication Number: US-2023148839-A1

Title: Disposable endoscope

Description:
BACKGROUND OF THE INVENTION 
     Endoscopes may be reusable, yet, for the sake of hygienic requirements, the device must be washed or otherwise sterilized after use with each patient. There is a need for a device and method enabling reuse of an endoscope without tampering with the hygienic requirements and with minimized repeating sterilization operations. 
     SUMMARY OF THE INVENTION 
     An endoscope device is disclosed comprising a disposable unit that includes an endoscopic insertion tube comprising an optical guide, having a proximal end and a distal end, for imaging a distal object. The disposable unit may also include an interface unit and a housing defining a confined space. The endoscope device may also include a reusable unit configured to be disposed and secured inside the housing of the disposable unit and comprising a receiver to receive, via the interface unit, image data of the imaged distal object. 
     In some embodiments of the invention, the interface unit includes an optical coupler. 
     In some embodiments of the invention, the receiver is adapted to receive an optical image from the optical guide via the optical coupler and to convert it to digital image data. 
     In some embodiments of the invention, the receiver includes an optical sensor. 
     In some embodiments of the invention, the disposable unit further includes a navigation mechanism for manipulating the distal tip of the insertion tube. 
     In some embodiments of the invention, the reusable unit further includes a navigation lever to operate the navigation mechanism. 
     In some embodiments of the invention, the endoscope device further includes a light source. 
     In some embodiments of the invention, the light source is disposed within the reusable unit, wherein the insertion tube further comprises an illumination guide to guide light from the illumination source to the distal end of the insertion tube. 
     In some embodiments of the invention, the light source is disposed at the distal end of the insertion tube. 
     In some embodiments of the invention, the optical guide includes a multicore fiber. 
     In some embodiments of the invention, the endoscope device further includes a focusing unit for enabling focusing the image by means of controlling the distance between the proximal end of the optical guide and the receiver. 
     In some embodiments of the invention, the endoscope device includes an aligning device for aligning of the proximal end of the optical guide with an optical axis of the receiver. 
     In some embodiments of the invention, the endoscope device further includes an extendable sterilization protecting flexible sleeve configured to be rolled off an aft end of the disposable unit and enclose a cable leading from the reusable unit to a control unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which: 
         FIGS.  1 A and  1 B  are schematic illustrations of an endoscope comprising a reusable unit and a disposable unit, in disassembled ( 1 A) and in assembled ( 1 B) positions, respectively, according to some embodiments of the present invention; 
         FIGS.  2 A- 2 D  are schematic illustrations of an endoscope with reusable and disposable units shown in top view and side view in disassembled position, and in top and side view in assembled position, respectively, according to some embodiments of the invention; 
         FIGS.  2 E and  2 F  are isometric 3D views of endoscope  200  shown in disassembled position and in assembled position, respectively, according to some embodiments of the invention; 
         FIG.  3    is a schematic illustration of the inside elements of a reusable part and of a disposable part of an endoscope in general view, according to some embodiments of the invention; 
         FIG.  3 A  is a schematic illustration of the inside elements of the front end of an endoscope, according to some embodiments of the invention; 
       FIGS.  3 A 1  and  3 A 2  are simplified schematic illustrations demonstrating aspects of the interface between a disposable unit and a reusable unit, according to some embodiments of the invention; 
         FIG.  3 B  is a schematic illustration of the inside elements of the central part of an endoscope, according to some embodiments of the invention; 
         FIG.  3 C  is a schematic illustration of the inside elements of the rear part of an endoscope, according to some embodiments of the invention; 
         FIGS.  4 A and  4 B  are a schematic isometric view of an endoscope showing a navigation lever of a shaft navigation system, and a view with removed cover of the front end of an endoscope depicting the shaft navigation mechanism, according to some embodiments of the invention; 
         FIGS.  4 C ,  4 C 1  and  4 C 2  are schematic partial isometric illustrations of a back cover of a disposable endoscope unit, according to embodiments of the invention; 
         FIG.  5    a schematic illustration of a sleeve for preserving the required level of cleaning of the reusable part of an endoscope, according to some embodiments of the invention; and 
         FIG.  6    schematically depicts means for preserving the required level of cleaning of reusable endoscopic equipment while using disposable endoscope insertion tube according to some embodiments of the invention. 
     
    
    
     It will be appreciated that, for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. 
     DETAILED DESCRIPTION OF THE INVENTION  
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention. 
     According to some embodiments of the invention an endoscope may be reusable in an affordable manner, meaning with minimized sterilization efforts and without tampering with hygienic requirements. According to some embodiments of the invention, only a part of the endoscope, e.g., the endoscope insertion tube, may be disposable. The disposable insertion tube of the endoscope may comprise only minimal essential elements, thereby minimizing the production costs for the disposable insertion tube. Use of a disposable insertion tube may be highly advantageous as it may decrease the risk for cross contamination between patients as well as reduce the need for a sterilization process, while requiring replacement of only a portion of an endoscope (the disposable insertion tube). 
     Some embodiments of the present invention relate to endoscopes, multicore endoscope fibers and configuration and operation methods. Multicore fibers, according to some embodiments, may have a large number (e.g., hundreds or thousands) of cores and may incorporate working channel(s) and/or additional fibers. The fiber used may be provided in different optical configurations to capture images of tissue and objects at the distal tip of the endoscope, and to enhance a wide range of optical characteristics of the obtained images, such as resolution, field of view, depth of field, wavelength ranges, etc. Near-field imaging as well as far-field imaging may be implemented in the endoscopes, according to some embodiments of the invention, and the respective optical features may be utilized to optimize imaging. Optical elements may be used at the distal tip, or the distal tip may lack any lenses. Diagnostics and optical treatment feedback loops may be implemented, and illumination may be adapted to yield full color images, depth estimation, enhanced field of view and/or depth of field and additional diagnostic data. 
     Various embodiments of multicore endoscope fibers may be used. An endoscope, according to some embodiments of the present invention, may implement far field imaging, i.e., have the image formed at the proximal end of the endoscope fiber, while another endoscope, according to some embodiments, may implement near field imaging, i.e., have the image formed at the distal end of the endoscope. Both far field and near field implementations, may have distal optical elements between the imaged objects or tissues and the distal tip of the endoscope, or may operate without such distal optical elements. Each of the four combinations (far field with and without distal optical elements and near field with and without distal optical elements) has different features, advantages and disadvantages, and may be selected according to specific implementation scenarios. Alternation of the combination may be carried out between applications or in real time, to combine advantages of different configuration types. It is further noted that endoscopes may be designed to have several combinations, e.g., a part of the fiber face (or certain fiber modules) having distal optics for imaging far objects and another part of the fiber face (or other fiber modules) lacking distal optics for microscopic imaging. 
     Endoscopes, according to some embodiments, may lack any optical elements at the distal tip. Such lens-less embodiments may implement either far-field or near-field imaging, and may utilize structural features to enhance optical resolution, apply super-resolution methods and retrieve wave front information while reducing crosstalk between the cores. 
     Endoscopes, according to some embodiments of the invention, may have full tip cross sections or have working channel(s) within the imaging fiber characterized by different configurations and uses, integrating additional fibers etc., in which case the cores and optical elements may be configured to overcome reduction of the field of view due to the incorporation of the working channel. 
     Various configurations of large number of cores in the endoscope fiber, according to some embodiments of the invention, may provide solutions to various issues such as reducing crosstalk between the fibers, overcoming material losses, achieving enhanced resolution by different methods, providing required mechanical characteristics and optimizing the imaging performances of the endoscope fibers. Endoscopes, according to some embodiments of the invention, may serve for different purposes, e.g., may be designed as a laparoscope or an ureteroscope, etc. 
     A micro endoscope, according to some embodiments of the invention, may be constructed from a large number of cores (e.g., one hundred cores or more, hundreds of cores, thousands of cores, in certain embodiments tens or hundreds of thousand cores per fiber or fiber module, reaching over a million cores in certain fiber endoscopes), where each core may be responsible for transferring a single or a large number of spatial degrees of freedom out of which at the output, proximal end (the end which is external to the patient body), a high resolution color image may be constructed. Multi-core fiber, according to some embodiments of the present invention, may exhibit a high degree of flexibility in its optical design, which may be utilized and adapted for specific applications, for example for ureteroscopes with a large working channel and a small external diameter or for laparoscopes with a very high resolution obtained at a small external diameter. 
     According to some embodiments of the invention, the endoscope may be divided into two main parts: a reusable endoscope handle that may include the majority of and the more expensive functionalities of the endoscope, such as the more complicated and expensive optical units (e.g. camera, image initial processing means and electronics), and a detachable and disposable endoscope insertion tube (or head) that may include a simpler and relatively cheap optical setup, endoscope image conducting guide, such as an optical fiber or a fiber bundle (e.g., multicore fiber, with a multitude of cores) and optionally lighting guide or guides (e.g., one or a plurality of cores in the fiber) for guiding illumination to the distal end of the insertion tube. 
     The endoscope insertion tube may include a fiber-based light conduit means and specific optic and mechanics connecting means, adapted to firmly attach the disposable endoscope insertion tube to the reusable endoscope handle. In some embodiments, the light source may be disposed at the distal end of the endoscope, e.g., using a suitable LED (light emitting diode) as a light source. A universal mounting interface at the front end of the endoscope handle may allow the use of application specific, exchangeable endoscope insertion tubes having different capabilities. An electronic-dense reusable handle allows functionality with various different single-use disposable insertion tubes. The disposable endoscope insertion tube may comprise a housing located at a proximal end of the insertion tube, adapted to accommodate and envelope the endoscope handle in a way that protects it, shielding it from outside physical contact and contamination, and preserving its sterilization. The entire endoscope may be covered with a sealable (e.g., plastic, rubber) cover covering both parts (disposable and reusable) including the electrical cable connected to the reusable handle. When desired, e.g., at the end of usage, the handle may be detached from the disposable endoscope insertion tube and extracted from the housing, while the disposable endoscope insertion tube with the housing is disposed of or discarded. 
     The connection between the handle and the disposable endoscope insertion tube may include a mechanical connector that could be based on various configurations including magnets located at both sides of the connecting interface, mechanical rotation-based clips, mechanical translation-based clips (catching both parts when rotating one part in respect to the other), screw like/bayonet-type connection based on rotation, and the like. 
     Reference is made now to  FIGS.  1 A and  1 B , which are schematic illustrations of endoscope  100  in disassembled and in assembled positions, respectively, according to some embodiments of the present invention. Endoscope  100  comprises two main parts: a reusable endoscope handle  102  and a disposable endoscope insertion tube  104 . Disposable endoscope insertion tube  104  comprises endoscope handle housing  104 A, adapted to sealingly accommodate reusable endoscope handle  102  in it. Disposable endoscope insertion tube  104  further comprises endoscope handle interface unit  104 B, endoscope optical probe unit  104 C and endoscope locking means  104 D. 
     Reusable endoscope handle  102  comprises endoscope body  102 A which may comprise electronics, power source, communication unit, etc., according to a specific design. Reusable endoscope handle  102  further comprises endoscope disposable insertion tube interface unit, adapted to support and enable transfer, communication and exchange of optical and electrical signals and data, according to a given specific design. Interface unit  102 B may provide, according to some embodiments, non-contact interface, e.g., using only optical coupling with disposable endoscope insertion tube. In such embodiments, disposable insertion tube may require inclusion of power source (not shown in  FIGS.  1 A and  1 B ). 
     Reusable endoscope handle  102  further comprises pull-out means  102 C adapted to enable pulling reusable handle  102  out of housing  104 A in a sterilization-preserving manner. After handle  102  is pulled out of housing  104 A, disposable insertion tube  104  may be disposed of and reusable handle  102  may be re-used in a future procedure. 
     When handle  102  is inserted into housing  104 A, in preparation for medical procedure, handle  102  should, in a preferred embodiment, be inserted fully into the housing so that locking means  104 D can be operated to lock handle  102  securely inside housing  104 A, e.g., by pushing a jig into recess  102 D made in the outer face of handle  102 /using a back cover that will lock the system. 
     When handle  102  is properly located and locked inside housing  104 A, interface units  102 B and  104 B should, in a preferred embodiment, be placed against each other in a way that enables connection, communication and signals exchange between handle  102  and disposable insertion tube  104 , according to the specific design. In some embodiments, the interface may be made with no mechanical/electrical connection, relying on, for example, optical coupling. 
     Reference is made now to  FIGS.  2 A,  2 B,  2 C and  2 D , which are schematic illustrations of endoscope  200  with reusable and disposable units shown in front view and side view in disassembled position, and in front and side view in assembled position, respectively, according to some embodiments of the invention Similar to endoscope  100 , endoscope  200  comprises two main parts: a reusable unit  202  and a disposable unit  204 . As seen in  FIGS.  2 A and  2 B , the shape and size of reusable unit  202  fits slidably into a housing made in the major part of the rear end of disposable unit  204 . When reusable unit  202  is inserted into the housing in disposable unit  204 , reusable unit  202  is enclosed fully in disposable unit  204 . 
     Reference is made now also to  FIGS.  2 E and  2 F , which are isometric 3D views of endoscope  200  shown in disassembled and in assembled position, respectively, according to some embodiments of the invention. The selected viewing angle of  FIGS.  2 E and  2 F  clearly demonstrates the complete accommodation of reusable unit  202  inside the housing made in disposable unit  204 . 
     Reference is made now to  FIG.  3   , which is a schematic illustration of the inside elements of the reusable part  302  and disposable part  304  of endoscope  300  in general view, according to some embodiments of the invention. In order to enable clear understanding of the embodiment presented in  FIG.  3   , the inside view of endoscope  300  is partitioned into three different views: the frontmost view (the view that is closest to the connection to the endoscope insertion tube) as depicted in detail in  FIG.  3 A , the central view as depicted in  FIG.  3 B , and the rearmost view as depicted in  FIG.  3 C . 
     Reference is made now to  FIG.  3 A , which is a schematic illustration of the inside elements of the front end of endoscope  300 , according to some embodiments of the invention. Endoscope insertion tube  3010  exits the frontmost end of endoscope  300 , and in the inside, insertion tube  3010  splits to fiber/multicore fiber  3020  and light waveguide  3030 . Light waveguide  3030  ends with light waveguide interface unit  3032 , e.g., optical coupler. Fiber/multicore fiber  3020  ends with fiber interface unit  3022 , e.g. optical coupler. Both interface units,  3032  and  3022  are held by interface bed unit  3060 , which is part of disposable unit  304 , as is explained in detail below. The ends of interface units  3022  and  3032  form the interface to reusable unit  302 . The example described herein demonstrates optical coupling of the optical image transmitted by fiber  3020  and the light transmitted towards waveguide  3030 , yet it would be apparent that other suitable means for coupling may be used and are within the ambit of the invention. On the other side of interface bed  3060  (the right side of it in the drawing), elements of reusable unit  302  are presented. Optical module  3050  is adapted to receive optical data transmitted by fiber  3020  and to convert it into digital representation of the image. Optical module  3050  ends, at its side facing interface bed  3060 , with shaped protruding end that is adapted to assist in optically aligning fiber  3020  with the central optical axis of optical module, as is explained in detail below. Light source  3040  is disposed close to optical module  3050  and is substantially parallel to it, and its light beam is aimed towards light waveguide interface unit  3032 . When reusable unit  302  is fully inserted and properly situated inside disposable unit  304 , light source interface unit  3042 , disposed at the front end of light source unit  3040 , tightly interfaces with the rearmost end of waveguide interface unit  3032 , thereby ensuring good transmission of the light to the wavegu ide. 
     Reference is made now to FIGS.  3 A 1  and  3 A 2 , which are simplified schematic illustrations demonstrating aspects of the interface between disposable unit  304  and reusable unit  302 , according to some embodiments of the invention. In order to ensure good enough optical coupling of the light transmitted to the endoscope insertion tube and of the optical image received from the optical guide, certain requirements need to be met. In the light path, good and efficient transfer of the light energy should be provided in order to minimize light energy loss in the interface between the light source interface unit  3042  and the waveguide interface unit  3032 . As is known in the art, in order to minimize light loss during pass from medium to medium, both should have same refraction coefficient, or as close as possible to each other. This requirement can easily be satisfied by proper selection of the transparent materials used for production. In some embodiments, using light source disposed at the distal end of the endoscope, e.g., LED, instead of optical coupling for transmitting light to the endoscope, an electrical coupling may be used for providing electrical power to the LED. 
     In some embodiments of the invention, the layer at the interface plane may be as thin as possible so that light passing through it will experience minimal losses. In order to satisfy this requirement, light source unit is slidably disposed inside reusable unit  302  such that it may slide back and force parallel to an imaginary longitudinal axis (ILA) of reusable unit  302 . Light source unit  3040  may be disposed with springy element  3048  supporting between light source  3040  and the body of reusable unit  302 . When reusable unit  302  is not coupled with disposable unit  304 , springy element  3048  is unloaded and the front end of light interface unit  3042  protrudes beyond light interface plane (LIP). When units  302  and  304  are coupled, light interface unit is pushed backwards by waveguide interface unit  3032 , and springy element  3048  retracts and provides predetermined coupling force that ensures sufficient optical coupling for the light. 
     In order to ensure good transfer of images collected by fiber unit  3020  to optical module  3050 , in addition to providing good light transmission at the interface plane, accurate transfer of the optical image should also be provided. When coupling optical image source and optical image destination units, the coupling should be set in three main axes X-Y-Z of the interface, so that the optical axes of the source and the destination are aligned and optical focus is provided. In order to ensure self-alignment of the optical axes when fiber interface unit  3022  and optical module  3050  are coupled, the interface plane of fiber interface unit  3022  may be shaped as a conical depression  3022 A made with its wider opening facing the housing (such as housing  104 A of  FIG.  1 A ) of disposable unit  304 . Fiber  3020  may end exactly in the middle of the narrower opening of conical depression  3022 A. Waveguide interface unit  3022  may be slidably disposed in interface bed  3060  so that is free to slide in the X-Y plane of interface bed  3060 , but maintains accurate location in the Z axis. Before coupling, interface unit  3022  may be located in the X-Y plane so that the center of conical depression  3022 A is located approximately at the X-Y coordinates of the expected X-Y coordinates of the mutual optical axis of the coupled units  302  and  304 . The front end  3052  of optical module  3050  may be formed as protrusion (e.g., a conical protrusion) that matches the conical depression  3022 A in size of the wide and narrow bases and the cone angle. When reusable unit  302  is inserted into its housing in disposable unit  304  and approaches interface bed  3060 , the front and narrower end of conical protrusion  3052  may enter into the wide opening of conical depression  3022 A and gradually align its optical axis with that of fiber unit  3020 , by enforcing the required movement(s) in the X-Y plane until fiber interface unit  3022  fully aligns with optical module  3050 . Description of adjustment of the focus in this embodiment is described herein after. 
     Reference is made to FIG.  3 A 2 , which is a schematic simplified block diagram of a focus unit for adjusting optical focus for the image transmitted by fiber unit  3020  to optical module  3050 , when reusable unit  302  and disposable unit  304  are coupled. Mechanical accuracy of the reusable unit  302  may be ensured during production. However, the disposable unit  304  may be subjected to less accurate manufacturing standards, in order to reduce production costs. As a result, when reusable unit  302  and disposable unit  304  are coupled, the actual distance between the end of fiber interface unit  3022  and optical module  3050  may vary from one disposable unit to another one by unacceptable variations range. In order to ensure accurate focusing, optical module  3050  may be made with a transparent front face  3053  so that the light sensitive plane  3052 ′ is located at an accurate pre-determined optical gap (PDOG) distance from front face  3053 . Fiber interface unit  3022  may be disposed in interface bed  3060  with certain freedom of movement along Z axis and may be located so that, when units  302  and  304  are not coupled, its front end protrudes slightly forward (toward the housing of unit  302 ) of the image interface plane (IIP). Fiber interface unit  3022  may be made with certain flexibility of movement along Z axis and its movement backwardly (towards fiber unit  3020 ) may cause springy return force due to certain level of flexibility of the fiber unit. When reusable unit  302  is fully inserted into its place inside the housing in disposable unit  304 , front face  3053  slightly pushes fiber interface unit  3022  backwardly against return force of fiber unit  3020 . As a result, fiber interface unit is forced to touch front face  3053 , and, thereby, the optical gap between fiber interface unit and optical module  3050  is guaranteed. 
     Reference is made now to  FIG.  3 B , which is a schematic illustration of the inside elements of the central part of endoscope  300 , according to some embodiments of the invention. In order to ensure good optical coupling of light source  3040  with light waveguide interface  3032 , light coupling self-adjustment means may comprise lighting unit  3044  coupled to sliding shaft  3046  which is pushed towards the front end of disposable unit  302  by springy element  3048 . When reusable unit  302  is fully inserted into its housing in disposable unit  304 , lighting unit  3044  is pushed back slightly by waveguide interface unit  3032  and causes springy element  3048  to retract and induce coupling force of lighting unit  3044  onto waveguide interface unit  3032 . 
     In order to enable adjustment of optical focus in the interface between optical module  3050  and fiber interface unit  3022  (i.e., setting the distance between the units along the optical axis), a focusing unit may comprise springy element  3056  housed in a cavity  3054  made in optical module  3050 . Springy element  3056  is disposed and designed to provide continuous force that pushes optical element toward the rear end of reusable unit  302 . Optical module may be pushed forward toward the front end of reusable unit  302 , as is explained herein below regarding  FIG.  3 C . 
     Reference is made now to  FIG.  3 C , which is a schematic illustration of the inside elements of the rear part of endoscope  300 , according to some embodiments of the invention. Optical sensor  3072  (e.g., CMOS sensor) of optical module  3050  is made to be pushed forward by focus adjustment means  3070 , which comprises threaded unit  3074  threaded in threaded housing  3076 . Threaded housing  3076  is rotatably disposed within reusable unit  302  and ends on the outer rear face of reusable unit  302  with adjustment knob  3078 . When adjustment of focus requires optical module  3050  be brought closer to fiber interface unit  3022 , knob  3078  may be rotated by the user to force forward movement of optical module by turning knob  3078  in a direction that causes threaded unit  3074  to extract from threaded housing  3076 . When the required direction of adjustment is the opposite, adjustment knob  3078  may be turned to the other direction, causing threaded unit  3074  to retract into threaded housing  3076  and allowing springy element  3056  to push optical element  3050  backwardly, so that the imaged object is focused on optical sensor  3072 . 
     Reference is made now to  FIGS.  4 A and  4 B , which are a schematic isometric view of endoscope  400  showing a navigation lever  4010  of navigation system  4000 , and a view with removed cover of the front end of endoscope  400  depicting the navigation mechanism  4000 , according to some embodiments of the invention. Navigation system  4000  is of the one-plane, two directions type, as is known for several types of endoscopes. This type of navigation is based on the difference in the pulling force applied onto one of the two navigation wires compared to that applied onto the other one. When the pulling force is equal, the endoscope will be in its “rest position”. Navigation system  4000  comprises navigation lever  4010  that is disposed outside of the body of disposable unit  304  and is coupled by a common pivot to navigation disk  4020 . Navigation wires  4030 A and  4030 B are connected, at a proximal end (shown in  FIG.  4 B ) to navigation disk  4020 , each on one side of the center of rotation of disk  4020 , and at a distal end to either sides of the distal end of the insertion tube. When navigation level is moved by a user, it causes navigation disk  4020  to rotate and as a result to pull one of navigation wires  4030 A/ 4030 B and to release the other one. As a result, a difference in the forces exerted on the wires is applied, causing the distal end of the endoscopic insertion tube to bend in a first direction or in an opposite direction, and this way navigation can be performed. In order to direct the distal end of the endoscopic insertion tube in other directions, the user may rotate the reusable unit about the elongated axis, parallel to the direction of insertion of the endoscopic insertion tube. 
     Reference is made now to  FIGS.  4 C ,  4 C 1  and  4 C 2 , which are schematic partial isometric illustrations of a back cover of a disposable endoscope unit, in assembled and disassembled positions respectively, according to some embodiments of the invention.  FIG.  4 C  depicts a disposable unit  4100  having main body  4110  and back cover  4120  shown in a back cover closed position, according to some embodiments of the invention. Back cover  4120  may be made to securely cover back opening  4122  (FIG.  4 C 1 ) for example after a reusable unit (not shown) is inserted into it. Back cover  4120  may be hingedly connected at one end to hinge rest  4116  on the outer circumference of opening  4112  by means of hinge  4126 . Main part  4122  of back cover  4120  may comprise an opening  4128  in it, for example to allow endoscope cable to pass through it from the reusable unit outwardly. In order to securely lock back cover  4120  in its closed position, a locking mechanism may be used, comprising first locking member  4114  connected to disposable unit  4110  at one end and to second locking member  4124  at its other end. Second locking member  4124  may be equipped at its other end with locking pins  4124 A adapted to tightly pull-and-close main cover unit  4122  when locking pins on locking dents  4125  and pull them towards main body  4110  of disposable unit  4100 . 
     Reference is made now to  FIG.  5   , which is a schematic illustration of means for preserving the required level of cleaning of the reusable part of an endoscope, according to some embodiments of the invention. In order to enable reusing of a reusable unit, such as reusable unit  302 , without having to undergo full and lengthy sterilization protocol after each use, it is essential to protect the reusable unit during an endoscopic procedure so that its required level of cleaning will not be tampered with. According to some embodiments of the invention, this requires to enable operation of the endoscope in a way that will ensure that reusable unit is protected along the entire procedure in a required level of cleaning, including during the separation of the reusable unit from the disposable unit after the  procedure. According to some embodiments of the invention, disposable unit  5000  may be provided with a flexible thin sleeve  5010  that may be made of a sterilization-preserving material (e.g., as is used for sterilized gloves). Before use, sleeve  5010  may be disposed close to the opening of reusable unit housing (such as housing  104 A of  FIG.  1 A ) and may be in its folded position, for example it may be wrapped around the rear part of disposable unit like serpentine. Sleeve  5010  may have a length, in deployed position, substantially equal to the length of the endoscope cable that connects the endoscope to its control unit  5100  (e.g., about  3  meters). After insertion of a reusable unit into disposable unit  5000  sleeve  5010  may be unfolded and stretched along cable  5002  (described as  5010 ′) until the cable is fully or substantially fully covered. After the endoscopic procedure, the user may hold the end of sleeve  5010 ′ and carefully pull it back toward disposable unit  5000  without tampering with the sterilization of cable  5002 . After sleeve  5010 ′ has been folded back fully and optionally rolled over the rear end of reusable unit  5000  with its inside facing out, the rear end the reusable unit (not shown in this drawing) is revealed. At this stage, the user may use a sterilized hand, of himself or of another colleague, to carefully pull the reusable unit out of its housing in disposable unit  5000 , using for example pull-out means, such as pull-out means  102 C of  FIG.  1 A . After the reusable unit has been removed and disposable unit  5000  has been taken away, the risk of tampering with the sterilization of the reusable unit by the disposable unit ends, and the process may end until reuse of the reusable unit. 
     Reference is made now to  FIG.  6   , which schematically depicts endoscope system  6000  comprising a reusable endoscopic equipment unit  6110  and a disposable endoscope  6010 , according to some embodiments of the invention. Disposable endoscope  6010  may comprise endoscope insertion tube  6012 , that may comprise fiber unit (single or multi-core fiber), optional optical means (e.g., lens), lighting means (either disposed at the distal end or at the proximal end of the endoscope, endoscope handle  6011 , endoscope cable  6014  and disposable endoscope connector  6020 . Cable  6014  may comprise optical guiding means to provide the optical image acquired at the distal end of disposable endoscope to connector  6020  (e.g., the fiber unit may extend from the distal end to connector  6020 ). Cable  6014  may further comprise electrical conduit to power the lighting means of disposable endoscope  6010 , or light guide to enable transmission of light from a light source disposed in reusable endoscopic equipment  6110  to reach the distal end of endoscope insertion tube  6012 . According to this embodiment, disposable endoscope  6010 , extending from the distal end of insertion tube  6012  to connector  6020 , may be disposed of after use in a medical procedure for a first patient, and another, pre-sterilized disposable endoscope  6010  may be connected to reusable endoscopic equipment unit  6110  via connector  6120  and connector  6020 . The specific details of the connections inside connectors  6120  and  6020  may vary according to the specific embodiment. For example, connectors  6120  and  6020  may comprise optical interface to support providing of the optical image acquired at the distal end of insertion tube  6012  to the optical receiver in reusable endoscopic equipment unit  6110 . Connectors  6120  and  6020  may comprise optical interface to enable providing of light produced by lighting means disposed in reusable endoscopic equipment unit  6110  to be conveyed to the distal end of disposable endoscope  6010 , or in another embodiment the connectors may comprise electrical interface to enable powering a light source disposed in disposable endoscope  6010 . 
     In some embodiments disposable endoscope  6010  may comprise navigation means (not shown), for example like navigation means system  4000  that was described in conjunction with  FIGS.  4 A and  4 B . 
     According to this embodiment, sterilization of reusable endoscopic equipment unit  6110  may not need any special sterilization preserving means. Typically, control unit  6100  and reusable endoscopic equipment unit  6110  are located distal from a treated patient, and the end of cable  6014  that is connected to connector  6020  is not likely to be contaminated during the endoscopic procedure. Nevertheless, at the end of an endoscopic procedure, disposable endoscope  6010  may be disconnected from reusable endoscopic equipment unit  6110  without tampering with its sterilization, thereby enabling further uses of reusable endoscopic equipment unit  6110  without needing to sterilize it after each endoscopic procedure. 
     According to some embodiments of the invention, reusable endoscope unit may be used with a variety types of disposable endoscope insertion tubes, for a large variety of needs and goals. The various types of disposable insertion tubes should only comply with the interface design of the reusable unit mechanically and optically. 
     In some embodiments, the disposable unit of the endoscope may comprise, disposed at the distal end of the endoscope insertion tube or at its proximal end, a videoscope unit for acquiring the object image and to transmit it to the endoscope reusable unit by means of data signals. 
     The conversion of the optical image at the proximal end of the multicore fiber to digital image data may be done, according to some embodiments, by providing an optical sensor at the proximal end of the optical guide of the endoscopic insertion tube and converting the optical image to digital data, e.g., by means of rolling shutter technique as is known in the art. A communication interface may be provided to facilitate coupling of the optical sensor to a receiver in the reusable unit and transmitting the digital data from the optical sensor to the receiver. 
     While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.