Abstract:
The invention relates to a lighting system for endoscopic examinations having a lighting unit that includes at least two LED elements for illuminating an area of examination that is to be observed by means of an endoscope optic. To create a lighting system for endoscopic examinations that ensures a constantly sufficient illumination of the area of examination, it is proposed according to the invention that the direction of radiation of the lighting unit can be displaced between a direction essentially perpendicular to the direction of observation of the endoscope optic upon insertion into the area of examination and a direction essentially in the direction of observation of the endoscope optic after insertion into the area of examination.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims priority of German patent application No. 10 2005 045 729.0 filed on Sep. 23, 2005, the content of which is incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0002]     The invention relates to a lighting system for endoscopic examinations having a lighting unit with at least two LED elements for illuminating an examination area that is to be examined by an endoscope optic.  
       BACKGROUND OF THE INVENTION  
       [0003]     The use of endoscopes has successfully proven itself in surgery for many years, and serves in many cases as a minimally invasive alternative procedure to the conventional open surgery. To be able to examine the area of application and to operate there by means of the endoscope optic, which can take the classic form for instance of a relay lens system, a fiber image conductor, or else as an electronic image sensor chip (CMOS, CCD) for video image photography, it is absolutely essential to illuminate the area of examination as well as possible. Besides their use in human and veterinary medicine, endoscopic examinations have also proven effective in technical areas, for instance for examining hollow cavities. Even in these application areas, good illumination of the area of examination is indispensable for good imaging by the endoscope optic.  
         [0004]     The illumination of an area of investigation is normally provided by a light conductor, consisting of fiberglass clusters, by which light from an external light source is conducted into the area of examination. Because this lighting system, for instance for purposes of cooling and wiring, is technically very complex, it has been a familiar practice in the art for some time to use lighting systems that are provided with LED elements and are affixed on the distal end of the endoscope shaft. The advantage of these LED lighting systems mounted on the distal end is that they avoid coupling losses in the light conductors and the LED elements have a long useful life.  
         [0005]     The use of a lighting unit that includes a lighting system for endoscopic examinations with an LED element is, for instance, known from DE 100 61 107 A1. The disadvantage of the known lighting systems, however, is the low effective density that is to be produced associated with the LED elements, so that even with special arrangements of the LED elements on the distal front end of the endoscope shaft, it is only possible to produce an illumination of the area of examination that is not sufficient for all cases of application.  
         [0006]     Consequently it is the object of the invention to create a lighting system for endoscopic examinations of the aforementioned type, which ensures a constantly sufficient illumination of the area of examination.  
       SUMMARY OF THE INVENTION  
       [0007]     This object is fulfilled according to the invention in a manner characterized in that the LED elements of the lighting unit are arranged in such a way that the radiation direction of the lighting unit can be moved between a direction essentially perpendicular to the direction of observation of the endoscope optic upon its insertion into the area of examination, and a direction essentially in the direction of observation of the endoscope optic after insertion into the area of examination.  
         [0008]     Because of the displacement of the LED elements, according to the invention, in a direction essentially perpendicular to the direction of observation of the endoscope optic upon insertion into the area of examination, it is possible for the first time, in the use of LED elements for illuminating an endoscopic area of examination, not to be required to position the LED elements on the distal front surface of the endoscope and thus on an extremely restricted surface area. Displacing the lighting unit after insertion into the area of examination makes possible thereafter the sufficient illumination by means of the LED elements that now are illuminating in the direction of observation of the endoscope optic.  
         [0009]     According to a preferred embodiment of the invention, it is proposed that the LED elements of the lighting unit are arranged in a row. This arrangement of the LED elements in a row allows a flat and superimposed illumination of the area of examination from diverse angles of incidence, leading to improved depth perception.  
         [0010]     According to a practical embodiment of the invention, the lighting unit is positioned away from the distal front surface on the distal end of an endoscope shaft and thus in immediate vicinity of the endoscope optic. Alternatively, a lighting system can be configured according to the invention but as an autonomous instrument, which is introduced into the area of examination in addition to an endoscope optic.  
         [0011]     It is further proposed with the invention that, to improve the illumination of the area of examination, the lighting unit should consist of several lighting subunits that are equipped with LED elements and advantageously can be rotated with respect to one another on the endoscope shaft. By using several lighting subunits, each of which is equipped with LED elements, the total number of the LED elements available for illumination can be clearly increased. In addition, because of the mutual rotatability of the individual lighting subunits with respect to one another, diverse angles of incidence of the light can be produced.  
         [0012]     According to a preferred embodiment of the invention, the individual lighting units are arranged symmetrically to one another with respect to the longitudinal axis of the endoscope optic. It is also possible to have preferably two or even more lighting units present, which advantageously are arranged symmetrically to one another with respect to the longitudinal axis of the endoscope optic and thus constitute circle segments in cross-section (perpendicular to the longitudinal axis of the endoscope optic).  
         [0013]     To ensure a uniform illumination of the area of examination, the LED elements of the lighting unit or of the lighting subunits are, according to the invention, preferably arranged symmetrically to one another with respect to the endoscope optic.  
         [0014]     According to a first practical embodiment of the invention having a lighting system mounted on the distal end of an endocope shaft, it is proposed that the endoscope optic should be positioned in the area of the rotatable mounting of the lighting subunits on the endoscope shaft, so that the endoscope optic is positioned basically in a plane with the lighting subunits of the lighting system.  
         [0015]     With an alternative embodiment of the invention it is proposed that the endoscope optic configures the distal end of the endoscope shaft, while the lighting unit is positioned proximally displaced between the endoscope optic.  
         [0016]     To divert the heat produced by the LED elements of the lighting unit, it is further proposed with the invention that a heat-diverting system, in particular in the form of an electric conductor, should be positioned in the endoscope shaft.  
         [0017]     It is finally proposed with the invention that the endoscope optic should be coupled with an imaging system, which can capture tissue fluorescent images after the disconnection of the LED elements of the lighting unit. This time-dissolved fluorescence imaging is particularly possible in the use of blue luminescent LED elements, which irradiate blue luminescence at a wavelength of approximately 405 nm and stimulate the tissue to a xeno- or auto-fluorescence.  
         [0018]     Additional characteristics and advantages of the invention can be seen from the appended illustrations, in which six embodiments of a lighting system for endoscopic examinations according to the invention are depicted in exemplary manner. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1   a  shows a side view of a first embodiment of a lighting system according to the invention upon insertion into the area of examination.  
         [0020]      FIG. 1   b  shows an enlarged and partially cutout view of detail IB of  FIG. 1   a.    
         [0021]      FIG. 1   c  shows a side view of the lighting system of  FIG. 1   a  in inserted position.  
         [0022]      FIG. 2   a  shows a side view of a second embodiment of a lighting system according to the invention in the insertion position.  
         [0023]      FIG. 2   b  shows a partly cutout view of the depiction in  FIG. 2   a  in the inserted position.  
         [0024]      FIG. 2   c  shows a view from below of the depiction in  FIG. 2   b.    
         [0025]      FIG. 3   a  shows a side view of a third embodiment of a lighting system according to the invention in the insertion position.  
         [0026]      FIG. 3   b  shows a partly cutout view of the depiction in  FIG. 3   a  in inserted position.  
         [0027]      FIG. 3   c  shows a view from below of the depiction according to  FIG. 3   b.    
         [0028]      FIG. 4   a  shows a side view of a fourth embodiment of a lighting system according to the invention, in the insertion position.  
         [0029]      FIG. 4   b  shows a partly cutout view of the depiction in  FIG. 4   a  in inserted position.  
         [0030]      FIG. 4   c  shows a view from below of the depiction in  FIG. 4   b.    
         [0031]      FIG. 5   a  shows a side view of a fifth embodiment of a lighting system according to the invention in the insertion position.  
         [0032]      FIG. 5   b  shows a side view, at a 90 degree angle, of the depiction in  FIG. 5   a.    
         [0033]      FIG. 5   c  shows a perspective view of the depiction in  FIGS. 5   a  and  5   b  in the inserted position.  
         [0034]      FIG. 6   a  shows a perspective view of a sixth embodiment of a lighting system according to the invention in the inserted position.  
         [0035]      FIG. 6   b  shows a partly cut-out side view of the depiction in  FIG. 6   a.   
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]     The lighting systems illustrated in  FIGS. 1   a  to  6   b  serve to illuminate endoscopic areas of examination, independently of whether they are used in medical or technical endoscopy.  
         [0037]     In the illustrated embodiments the lighting systems consist of a lighting unit  2  that is positioned on the distal end of an endoscope shaft  1  and in turn includes at least two LED elements  3 . For observing the area of examination that is illuminated by means of the lighting unit  2 , on the distal end of the endoscope shaft an endoscope optic  4  is further positioned which can take the classical form of a relay lens system or can be a CCD or CMOS image sensor for video photography.  
         [0038]     All illustrated lighting systems have the peculiarity that the lighting unit  2  is positioned, not on the distal front surface of the endoscope shaft but laterally on the distal end area of the endoscope shaft  1 , so that the arrangement of the LED elements  3  is not restricted to the small front surface.  
         [0039]     As is explained hereafter in greater detail with reference to the various embodiments for configuring the lighting system, the LED elements  3  of the lighting units  2  are arranged on the endoscope shafts  1  in such a way that the direction of radiation of the lighting units  2  can be displaced between a direction essentially perpendicular to the direction of observation of the endoscope optic  4  upon insertion into the area of examination and a direction essentially in the direction of observation B of the endoscope optic  4 , after insertion into the area of examination.  
         [0040]      FIG. 1   a  shows the insertion of an endoscope shaft  1  by means of a trocar sleeve  5  into an area of examination, for instance a patient&#39;s abdominal cavity  6 . For this purpose the endoscope shaft  1  is inserted into the abdominal area  6  in the illustrated longitudinal straight position by means of the trocar sleeve  5  positioned in the abdominal wall  7 . This straight insertion direction corresponds to the actual direction of observation B of the endoscope optic  4 .  
         [0041]     As can be seen from the sectional depiction in  FIG. 1   b  of the distal end of the endoscope shaft  1  of  FIG. 1   a , the lighting unit  2  consisting of four LED elements  3  is positioned outside the distal front surface on the endoscope shaft  1  in such a way that the direction of radiation A of the LED elements  3  of the lighting unit  2 , upon insertion, points in a direction which is essentially perpendicular to the direction of observation B of the endoscope optic  4 , which this optic assumes in observing the area of examination.  
         [0042]     As can further be seen from  FIG. 1   b , the illustrated lighting unit  2  is constructed in such a way that the LED elements  3  are arranged symmetrically to one another with respect to the endoscope optic  4  configured as an opto-electronic image sensor.  
         [0043]     In order to observe and examine the area of examination, at least the distal area of the endoscope shaft  1  that contains the lighting unit  2 , after insertion into the area of examination, can be rotated into the position shown in  FIG. 1   c , in which the direction of radiation A of the LED elements  3  of the lighting unit  2  corresponds essentially to the direction of observation B of the endoscope optic  4 . Because of the symmetrical arrangement of the LED elements  3  in a row around the endoscope optic  4 , as can be seen in  FIG. 1   c , it is possible to produce a much larger density capacity for illuminating the area of examination than is possible with the arrangement of the LED elements  3 , as known in the art, on the small distal front surface of the endoscope shaft  1 .  
         [0044]     The embodiments of lighting systems for endoscopic examinations shown in  FIGS. 2   a  through  4   c  are distinguished from the previously described configurations according to  FIGS. 1   a  through  1   c  in that the lighting units  2  of the three illustrated alternative forms of construction each consist of two lighting subunits  2   a , which are positioned to rotate around guide points  8  with respect to one another on the endoscope shaft  1 . Alternatively it is also possible, however, to provide three, four, or more lighting subunits.  
         [0045]     In the second embodiment seen in  FIGS. 2   a  through  2   c , the distal area of the endoscope shaft  1  is configured as divided in the axial direction of the endoscope shaft  1  for configuring the two lighting subunits  2   a . The two lighting subunits  2   a , which can each rotate by one guide point  8 , each have four LED elements  3  as well as an endoscope optic  4  configured as an opto-electronic image sensor, such that the LED elements  3  in turn are arranged symmetrically around the endoscope optic in order to ensure a uniform illumination of the area of examination.  
         [0046]     In this embodiment, in which several distal endoscope optics  4  are used, which are connected by light-conducting fibers with an imaging device (screen), either several individual images are shown each from other viewing perspectives, so that possibly only individual images can be shown, even by switching, or else a stereo view is made up of two or more individual images. The latter alternative produces images with a very good three-dimensional or depth effect.  
         [0047]      FIG. 2   a  shows the extended straight insertion position of the endoscope shaft  1 , in which the flat surfaces of the two lighting subunits  2   a , equipped with the LED elements  3  and the endoscope optics  4 , are closed and firmly contiguous to one another and form an essentially flush distal extension of the endoscope shaft  1 .  
         [0048]     For superimposition into the examination positions indicated in  FIGS. 2   b  and  2   c , the lighting subunits  2   a  are rotated around the guide points  8 , for instance by an actuation element mounted in the endoscope shaft  1 , in particular a push-pull rod or a Bowden cable, until the direction of radiation A of the LED elements  3  of the lighting subunits  2   a  essentially corresponds to the direction of observation B of the endoscope optic  4 .  FIG. 2   b  shows a transitional position that can be used for examination purposes, in which the LED elements  3  illuminate the area of examination from diverse angles of inclination.  
         [0049]     The third embodiment, shown in  FIGS. 3   a  to  3   c , is distinguished from the previously described embodiment shown in  FIGS. 2   a  through  2   c  in that the surfaces of the two lighting subunits  2   a  equipped with the LED elements  3  and endoscope optics  4  are not flat in form but rather comb-like with protuberances  9  and indentations  10 . As can be seen in  FIG. 3   a , the protuberances  9  and indentations  10  of the two lighting subunits  2   a  are arranged here so that, in the insertion position of the endoscope shaft, they engage with one another in form-locking position and the two lighting subunits  2   a  in turn form an essentially flush distal extension of the endoscope shaft  1 .  
         [0050]     The LED elements  3  and the opto-electronic image sensors of the endoscope optics  4  in this embodiment are each positioned on the free ends of the protuberances  9 , such that the illustrated embodiment for each lighting subunit  2   a  includes two LED elements  3  as well as an endoscope optic  4  that is centered between the LED elements  3  and takes the form of an opto-electronic image sensor.  
         [0051]     Alternatively to the embodiments illustrated in  FIGS. 2   a  through  3   c , in which the opto-electronic image sensors of the endoscope optics  4  are positioned only on the lighting subunits  2   a , it is also possible of course to position at least one opto-electronic image sensor as sole, or additional endoscope optic  4  in the area of the rotatable positioning of the lighting subunits  2   a  on the guide points  8 .  
         [0052]      FIGS. 4   a  through  4   c  show an additional embodiment, in which the lighting unit  2  again consists of two lighting subunits  2   a  that can rotate with respect to one another around guide points  8 . In this embodiment the distal end of the endoscope shaft  1  is configured by a bridge-shaped web, which spans the two lighting subunits  2   a  in the insertion position shown in  FIG. 4   a.    
         [0053]     As can be seen in particular from  FIG. 4   b , the two lighting subunits  2   a  are positioned on the guide points  8  so that they can unfold laterally out of the web  11 . The two rotatable lighting subunits  2   a  in this embodiment each have four LED elements  3  as well as one endoscope optic  4  configured as opto-electronic image sensor, such that the LED elements  3  again are arranged symmetrically around the endoscope optic  4  in order to ensure a uniform illumination of the area of examination.  
         [0054]     In addition, in this embodiment another opto-electronic image sensor serving as endoscope optic  4  is positioned on a distal front surface  11   a  of the web  11 .  
         [0055]     In the straight insertion position shown in  FIG. 4   a , the front surface  11   a  of the web  11  extends beyond the lighting subunits  2   a  into the unfolding direction of the lighting subunits  2   a  in such a way that the front surface  11   a  of the web  11  extends the endoscope shaft essentially flush on the outer surfaces of the two lighting subunits  2   a.    
         [0056]     In the fifth embodiment, shown in  FIGS. 5   a  through  5   c , the one-part lighting unit  2  is positioned so that it can rotate around a pivot axis  12  on the distal end of the endoscope shaft. The distal end of the endoscope shaft  1  is configured with two arms  13  for this purpose, in such a way that the lighting unit  2  is positioned so that it can rotate around the pivot axis  12  between the two distal arms of the endoscope shaft  1 .  
         [0057]     In the insertion position illustrated in  FIGS. 5   a  and  5   b , the lighting unit  2  is rotated in such a way that it is directed in the axial direction of the endoscope shaft  1  and thus can be inserted into the area of examination with the endoscope shaft in straight position.  
         [0058]     In the position inserted into the area of examination, the lighting unit  2 , as can be seen from  FIG. 5   c , is rotated by 90 degrees until it is situated perpendicular to the axial direction of the endoscope shaft  1 . A stop  14  configured on the endoscope shaft  1  restricts, on the one hand, the angle of rotation of the lighting unit  12  and, in addition, allows only a rotation in a direction around the pivot axis  12 .  
         [0059]     As can also be seen from  FIGS. 5   a  and  5   c , the lighting unit  2  in this embodiment includes four LED elements  3  as well as an endoscope optic  4  configured as an opto-electronic image sensor, such that the LED elements  3  again are positioned symmetrically around the endoscope optic  4  in order to ensure a uniform illumination of the area of examination.  
         [0060]     Alternatively to the embodiment depicted in  FIGS. 5   a  through  5   c , similar configurations can be realized in which, on the proximal end from the lighting unit  2  that can rotate by 90 degrees, one or more additional lighting units  2  are positioned so that they can rotate around pivot axes  12  in the endoscope shaft  1 , and these additional lighting units  2  then, as a rule, are each equipped only with LED elements  3  to illuminate the area of examination and are positioned at an 180 degree angle to one another in the endoscope shaft  1 . To be able to examine the area of examination also by a stereo view, it is necessary to equip at least one of the additional lighting units  2  additionally with an endoscope optic  4 .  
         [0061]     In the sixth embodiment of a lighting system, illustrated in  FIGS. 6   a  and  6   b , the lighting unit  2 , similarly as in the depiction of  FIGS. 1   a  through  1   c , forms the distal end of the endoscope shaft  1 , which in this case however is configured as a mere conductor for the supply of the LED elements  3  and of the endoscope optic  4 . In this embodiment as well, the lighting unit  2  includes four LED elements  3  as well as an endoscope optic  4  configured as an opto-electronic image sensor, such that the LED elements  3  again are positioned symmetrically around the endoscope optic  4 .  
         [0062]     In the insertion position, not illustrated, the lighting unit  2  forms the extended straight extension of the endoscope shaft  1 . The lighting unit  2  then is at an angle with respect to the endoscope shaft  1  only in the area of examination, as this is shown in  FIGS. 6   a  and  6   b.    
         [0063]     As previously illustrated and described, all lighting systems have the peculiarity that the lighting units  2  are not positioned on the distal front surface of the endoscope shaft  1 , but instead laterally on the distal end area of the endoscope shaft  1 , so that the arrangement of the LED elements  3  is not restricted to the small front surface. For this purpose the LED elements  3  of the lighting units  2  are arranged on the endoscope shafts  1  in such a way that the direction of radiation of the lighting units  2  can be displaced between a direction essentially perpendicular to the direction of observation of the endoscope optic  4  upon insertion into the area of examination and a direction essentially in the direction of observation B of the endoscope optic  4  after insertion into the area of examination.  
         [0064]     For configuring the LED elements  3 , preference is given to using LED elements  3 , which for instance radiate blue light at a wavelength of about 405 nm and stimulate the tissue to a xeno- or auto-fluorescence. The endoscope optic  4  in this embodiment of the time-dissolved fluorescence imaging is advantageously coupled with an imaging system that can record tissue fluorescence images after disconnection of the LED elements  3  of the lighting unit  2 .  
         [0065]     The advantage of the LED illumination to intracorporal fluorescence stimulation consists in the fact that the LEDs  3 , contrary to the short-wave lamps or mechanically shuttered constant lamps, can be switched with great precision. Thus, after a constant fluorescence stimulation, it is possible to disconnect and switch over to fluorescence stimulation (“fluorescence lifetime imaging”). In addition periodic stimulation can be performed precisely and thereafter the fluorescence can be produced periodically.