Abstract:
An endoscope optic including: an outer tube having an opening at an end face in an end region of the outer tube, a fiber tube disposed in the opening, the fiber tube containing an objective lens, and a fiber bundle for illuminating a region in front of the objective lens, the fiber bundle being provided at an outer periphery of the objective lens, wherein a distal end region of the fiber bundle being arranged in a distal aperture in the fiber tube, the aperture being surrounded by material of the fiber tube.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is based upon and claims the benefit of priority from PCT/EP2015/001529 filed on Jul. 24, 2015, which claims benefit to DE 10 2014 111 069.2 filed on Aug. 4, 2014, the entire contents of each of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Field 
         [0003]    The present disclosure generally relates to endoscopes, and more particularly to an endoscope and to a method for assembling an endoscope. 
         [0004]    Prior Art 
         [0005]    Endoscopes are used to observe a field of view, to which access is typically only enabled through a small opening. The endoscope has an endoscope optic with a lens. The endoscope optic can be formed as a separate component of the endoscope and inserted into the endoscope. In endoscopes, optical fibers are used to illuminate the field of view. For this purpose, a bundle of many optical fibers, i.e. a fiber bundle, is typically used to provide a sufficient light intensity. The fibers radiate the light at its end region in a relatively wide range of angles. Nevertheless, all fibers should preferably be oriented with their (main) beam direction towards the field of view. Other fibers provide disturbing brightness variations in the field of view. The fibers receive their appropriate orientation during the assembly of the endoscope optics. For sealing and fixing their orientation, the fibers at the distal end region are bonded with an adhesive and then polished. 
         [0006]    DE 10 2004 023024 B4 introduces an obliquely-viewing endoscope with an endoscope optic which has a lens that is directed angled downward towards the longitudinal axis of the endoscope optic axis. In such endoscope optics, optical fibers are arranged laterally next to the actual optics and above. The laterally arranged fibers are oriented parallel to the viewing direction of the lens looking obliquely downward. The upper fiber bundle extends on the other hand parallel to the longitudinal extension of the endoscope optics. The optic fibers are arranged between an outer casing tube or outer tube and an inner fiber tube. The fiber tube contains inside the actual optics with the distal lens obliquely looking downward. Recesses are provided on the outer region of the fiber tube to orient the optical fibers and fix them in their position. The optical fibers are inserted into these recesses, before the outer tube is then pulled over the distal end region of the endoscope optics. The optical fibers are pressed and oriented through the outer tube into the recesses of the fiber tube. Then the optical fibers at the end region of the endoscope optics can be bonded together, cut and polished on the end face. 
         [0007]    U.S. Pat. No. 4,850,342 introduces an endoscope optic in which a fiber channel is provided between the fiber tube and outer tube, which enables an orientation of the ends of the optical fibers in the end region through assembling the outer tube and fiber tube. 
         [0008]    U.S. Pat. No. 4,576,147 also relates to an endoscope optic in which an orientation through formation of a fiber channel between an inner fiber tube and an outer tube is only achieved upon assembly of the endoscope optic. 
         [0009]    A disadvantage of the known endoscope optics is that the final orientation of the optical fibers is only set with the final positioning of the outer tube as casing of the fiber tube. The assembly is therefore very complex and is to be performed manually. 
       SUMMARY 
       [0010]    An object is to create a generic endoscope with optical fibers illuminating the field of view in a targeted manner, in which the assembly is facilitated and the orientation improved. 
         [0011]    Such object can be achieved through an endoscope in which the distal end region of the fiber bundle is arranged in a distal aperture in the fiber tube of the endoscope optic. The aperture can be completely surrounded by material of the fiber tube, such as having an enclosed edge. In such configuration, the fiber tube has an aperture into which the optical fibers can be inserted. The aperture can pass through a wall of the fiber tube in a region with a thickening. The aperture can pass through the end face and/or at least a partial section of the end face of the fiber tube. The aperture can be adapted to receive the entire fiber bundle. By inserting the optical fibers into the aperture of the fiber tube, the fibers are already oriented, such as at their distal end regions. A correct orientation of the fiber ends is thereby only achieved in the fiber tube, without a slipping of the casing tube being necessary. The assembly of the endoscope is thus greatly facilitated. 
         [0012]    The optical fibers or fiber bundle can be attached in the aperture. For this purpose, the optical fibers can be attached, for example, by a clamping effect, by frictional forces and/or a canting. This attachment serves, for example, to prevent a slippage of the optical fibers during assembly of the endoscope optic, for example, during assembly of the casing tube. The attachment can take place permanently. For this purpose, an adhesive or the like can be used to achieve a permanent fixing and sealing. 
         [0013]    The lens can be oriented obliquely downward looking through the opening at an angle to the longitudinal axis of the fiber tube. Such an obliquely-looking endoscope can be used to observe a field of view lying away from the central longitudinal axis of the endoscope. This offers the advantage of an optimized field of view illumination. At the same time, an improved assembly of the endoscope or the endoscope optic is ensured. 
         [0014]    The longitudinal axis of the aperture and the longitudinal axis of the distal end of the fiber bundle or the optical fibers can be oriented at least substantially parallel to each other. The longitudinal axis of the distal end of the fiber bundle can correspond to the beam direction of the optical fibers. In such configuration, the aperture can define the orientation of the distal end of the fibers. A clean guidance of the fibers is facilitated by the parallel or at least almost parallel orientation of the longitudinal axis of the fiber bundle and viewing direction of the lens. For this purpose, the aperture can have a sufficient longitudinal extent, in order to achieve a sufficient guidance of the fiber bundle. The aperture can be accordingly arranged extending obliquely with respect to the longitudinal axis of the fiber tube. 
         [0015]    The orientation of the fiber bundle, such as its longitudinal axis or beam direction, can differ from the longitudinal axis of the aperture. This can be caused, for example, by a bending of the fibers. Such a bending can occur with an orientation of the end regions of the fibers, obliquely to the longitudinal extension of the endoscope optic. The oblique orientation can be provided for better illumination of the field of view. The bending of the fibers can take place in a bending region. Small deviations between the orientation of the aperture and the fiber ends can be compensated, for example, by a pre-tension. 
         [0016]    The longitudinal axis of the aperture and the viewing direction of the lens or the longitudinal axis of the fiber bundle can enclose an acute angle in the region in front of the lens. In such configuration, the aperture or the fibers can be oriented somewhat more obliquely with respect to the longitudinal axis of the endoscope than the lens or its viewing direction. An improved orientation of the fibers in the desired direction is thus achieved. The desired direction can be parallel to the viewing direction of the lens for optimal illumination of the field of view, such as in a region close in front of the lens. The main direction of the aperture can be oriented more obliquely than that of the lens. In such configuration, the curved fibers can obtain an optimal arrangement. This can be advantageous, since optical fibers with a curved arrangement typically differ from the ideal orientation. 
         [0017]    The angle between the longitudinal axis of the aperture or of the fiber bundle, such as its beam direction, and the field of view of the lens can be less than 20°, such as between 1° and 20°, such as between 2° and 6°. Such a slightly stronger tendency can be sufficient to compensate for a corresponding bending back of the fibers. Thus, an optimal illumination of the field of view can be achieved. 
         [0018]    The aperture can be formed at least substantially as a semi-circular or crescent-shaped milling groove. Such a geometric shape offers a broad field of illumination with, at the same time, optimum adaptation to the generally circular outer shape of the endoscope optic. At the same time, the available space can be optimally utilized. The aperture can be provided above the optic or the lens. 
         [0019]    The fiber bundle can end with the distal end region in the aperture. Likewise, the fiber bundle may be flush with the front edge of the fiber tube. Both orientations can cause the distal end region of the fiber bundle or the optical fibers to be arranged at an optimal position. At the same time, the greatest possible protection of the sensitive end face of the fibers may be achieved. 
         [0020]    Finally, a method for producing or assembling an endoscope or an endoscope optic for an endoscope, is also provided. The method includes disposing the fiber bundle into the aperture in the fiber tube, while the distal end region of the fiber bundle is disposed in the aperture, inserting the fiber tube into the outer tube, to position the fiber bundle relative to the fiber tube and outer tube, and fixing the fiber bundle in the aperture. Such method can further include smoothing and/or polishing an end face side of the fiber bundle. 
         [0021]    Such method simplifies the assembly considerably compared to the prior art. Here, the fiber bundle or the optical fibers are already oriented when inserted into the aperture of the fiber tube. The assembly of the outer tube or casing tube no longer affects the orientation of the fibers in practice. At most, the fiber bundle is provided with an additional fixing in the region between the fiber tube and the casing tube or outer tube. 
         [0022]    Both straight-viewing and obliquely-viewing endoscopes can be utilized in the endoscope optic and methods described above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    An embodiment will be described in more detail below with reference to the figures of the drawings. 
           [0024]      FIG. 1  illustrates a lateral sectional view of an endoscope optic for an endoscope in the assembled state, 
           [0025]      FIG. 2  illustrates a perspective rear view of a fiber tube of the endoscope optic, 
           [0026]      FIG. 3  illustrates a front view of the lens of the endoscope optic, 
           [0027]      FIG. 4  illustrates a lateral sectional view of the endoscope optic during the insertion of the fiber bundle, and 
           [0028]      FIG. 5  illustrates a lateral sectional view with the inserted fiber bundle. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]      FIGS. 1-3  show an endoscope optic  10  for an endoscope in the assembled state in a lateral sectional view. Such an endoscope optic  10  is inserted into an endoscope not illustrated here and thus used in combination. For this purpose, the endoscope has a corresponding receptacle for the endoscope optic  10 . 
         [0030]    The endoscope optic  10  has a fiber tube  11 , which is surrounded by an outer tube  12 . The end face  14  of the endoscope optic  10  is arranged obliquely to the longitudinal axis of the endoscope optic  10 . This end face  14  has an opening, such as a window opening  15 , which is configured, for example, to receive a circular window  16 . An optic system is provided inside the fiber tube (not illustrated). The viewing direction of the optic system is obliquely orientated in a direction  21  relative to a longitudinal axis  13  of the fiber tube  11 . 
         [0031]    The casing tube or outer tube  12  surrounds the entire endoscope optic  10  at least in the distal region, with the exception of the end face  14 . A fiber bundle  17  is arranged in the upper region of the endoscope optic  10 . The fiber bundle  17  ends at a distal end region with fiber ends  18  at the end face  14  of the endoscope optic  10 . The fiber ends  18  meet substantially at least in an almost right angle to the end face  14 . At the proximal end region of the fiber bundle  17 , coupled light passes through the fiber bundle  17  and exits from its end face  19  to illuminate the field of view of the endoscope optic  10 . 
         [0032]    The endoscope optic has an objective lens  22  in the region of the window opening  15 . The angle at which the objective lens  22  is oriented with its viewing direction  21  can, for example, be approximately 30°. This angle can be chosen depending on the scope of application of the endoscope optic  10 . The end face  14  with the window  16  built into the window opening  15  is generally arranged at the same angle. Optionally, a straight-viewing optic can also be used instead. 
         [0033]    The light output from the fiber end  18  thus extends mainly in a beam direction  20 . The optic or the objective lens  22  looks accordingly in a viewing direction  21 . In order to achieve sufficient illumination of the field of view of the optic, the beam direction  20  and the viewing direction  21  are arranged at least substantially parallel to each other. In order to achieve a better illumination directly in front of the objective lens  22  of the optic, the beam direction  20  can be arranged slightly inclined with respect to the viewing direction  21 . In this case, the beam direction  20  and the viewing direction  21  intersect in the region in front of the end face  14  of the endoscope optic  10  at an acute angle. The angle is typically less than 20°, such as less than 10°, or between 2° and 6°. 
         [0034]    As shown in  FIG. 1 , the fiber bundle  17  extends for the most part in a straight line and parallel to the longitudinal axis  13  of the endoscope optic  10 . Only in the distal end portion thereof does the fiber bundle  17  extend in the beam direction  20  to illuminate the field of view. 
         [0035]    In order to achieve an orientation of the fiber ends  18  to illuminate the field of view of the objective lens  22 , the fiber bundle  17  undergoes a bending in a bending region  23 . The fiber bundle  17  consists of a plurality of individual optical fibers  24 , which can be bent in a simple manner accordingly. The fibers  24  extend parallel to each other. 
         [0036]    The optical fibers  24  of the fiber bundle  17  are held for bending between a lower contact surface  25  and an upper contact surface  26  of an aperture  27  in the fiber tube  11 . The lower contact surface  25  is, as in the prior art, a component of the fiber tube  11 . 
         [0037]    In the prior art, however, the upper contact surface  26  is attached to the outer tube  12 . Accordingly, the distance between the lower contact surface  25  and the upper contact surface  26  can be increased for the assembly by sliding the outer tube  12  with respect to the fiber tube  11  in the prior art. The assembly is then performed by sliding the fiber tube  11  and outer tube  12  together in the correct position. 
         [0038]    However, according to the embodiment of  FIGS. 1-3 , both the lower contact surface  25  and the upper contact surface  26  are part of the fiber tube  11 . For this purpose, the aperture  27  is provided in the fiber tube  11 . The aperture  27  can be configured as an arcuate slot or opening. It thus forms the lower contact surface  25  and the upper contact surface  26  for the optical fibers  24 . 
         [0039]    Referring now to  FIGS. 4 and 5 , a method for assembling the endoscope optic is as follows: 
         [0040]    The optical fibers  24  of the fiber bundle  17  are inserted into the aperture  27  of the fiber tube  11 , as is illustrated in  FIG. 4 . The introduction of the fiber bundle  17  can take place along more or less a straight route. 
         [0041]    For further assembly, as illustrated in  FIG. 5 , the optical fibers  24  of the fiber bundle  17  are then bent downward somewhat and deposited on the top of the fiber tube  11 . This results in a bending of the fibers  24  in the region of the bending point  23  due to a curved transition region provided in this region. This region is located between the lower contact surface  25  and a recess on the fiber tube side as part of a fiber channel  28  to receive the optical fibers  24 . This fiber channel  28  is formed after the complete assembly of the endoscope optic  10  on the one hand by the top of the fiber tube  11  and on the other hand by the inside of the outer tube  12 . While the optical fibers  24  of the fiber bundle  17  are guided into the interior of the fiber channel  28 , the bending is maintained at the bending point  23 . 
         [0042]    In addition, a fixed mounting of the optical fibers  24  is thus provided in the aperture  27 . This takes place since the fibers  24  are curved and abut the fiber tube  11  or outer tube  12 . To fix the optical fibers  24  in the aperture  27 , the optical fibers  24  are usually also molded in position by an adhesive. In addition, fiber ends  18  protruding beyond the end face  14  are cut and provided with a polishing in the plane of the end face  14 . An end face  19  (see  FIG. 1 ) of the fibers  24  is thus formed. This can be in a plane with the end face  14 . 
         [0043]    The fiber channel  28  can provide sufficient space for a more or less loose guidance of the optical fibers  24  of the fiber bundle  17 . Meanwhile, the optical fibers  24  in the aperture  27  can be composed narrow, so that a stable orientation of the fiber ends  18  is thereby achieved. 
         [0044]    The embodiments described above, as well as other embodiments, can be realized both with straight and obliquely-viewing endoscopes. 
         [0045]    While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           10  endoscope optic 
           11  fiber tube 
           12  outer tube/casing tube 
           13  longitudinal axis 
           14  end face 
           15  window opening 
           16  window 
           17  fiber bundle 
           18  fiber ends 
           19  end face 
           20  beam direction 
           21  viewing direction 
           22  objective lens 
           23  bending region 
           24  optical fibers 
           25  lower contact surface 
           26  upper contact surface 
           27  aperture 
           28  fiber channel