Abstract:
The invention relates to an arrangement for a stereomicroscope, having an illumination apparatus ( 20 ) whose light lies in a regulatable spectral region. This illumination apparatus can be freely supplemented by at least one further illumination apparatus ( 30 ) whose light lies in likewise regulatable spectral regions identical to or different therefrom.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of the German patent application 10 2005 005 984.8 filed Feb. 9, 2005 which is incorporated by reference herein. 
     FIELD OF THE INVENTION 
     The invention relates to a stereomicroscope, preferably a surgical microscope, having an illumination source whose light, of a predetermined spectral range, is directable by means of an optical device onto a specimen to be viewed. The light of at least one further illumination system, in a different spectral region, can be selectably switched in. 
     BACKGROUND OF THE INVENTION 
     Fluorescence is a well-known method that, with the aid of tuned filters, conveys a defined excitation spectrum to a specimen, spectrally separates the response signal radiated by the specimen from the excitation light, and passes that signal on for observation and analysis. In the clinical field, for example, many applications are known which assist surgical operations and which mark, by way of the emitted fluorescence, the tissue that is to be resected. One particular example of the application of such a method using fluorescence devices integrated into a microscope are surgical microscopes for neurosurgery, which use photodynamic medications, known e.g. under the names aminolevulinic acid (ALA) or meso-tetrahydroxyphenyl chlorine (mTHPC), to permit more complete excision of certain tumors. 
     Another application relates, for example, to infrared angiography, in which light from the near-infrared (NIR) region is used for excitation, in order then to observe the specimen in the longer-wavelength spectral region. Other applications make use of invisible ultraviolet light. Other spectral regions, from ultraviolet to blue light and from there to red and on into the far infrared, are likewise possible. 
     At the point where a tissue or a specimen needs to be excited, a sufficiently intense excitation spectrum is of essential importance. When working, for example, with blue excitation light in the range from 380 to 420 nm, a specific fluorescence signal (e.g. 635 nm with ALA) will be obtained depending on the fluorescence ingredient that is used. 300-watt xenon light sources are generally used for this; they make available both normal microscopy white light and the blue light necessary for fluorescence, the latter by filtering and optimizing the spectral region from 380 to 420 and by careful selection of the xenon element. The same analogously applies, of course, to other spectral regions. Examples of such known microscopes or surgical microscopes are found, for example, in U.S. Pat. No. 6,510,338 or DE-A-195 48 913, in which the light of the illumination device is conveyed to the specimen being observed via optical waveguides and other optical devices. 
     A problem with these known microscopes is that in selecting the illumination source, a compromise must be made whose ultimate result is that the white-light quality cannot be optimized for observation, and that on the other hand, specifically when the blue-light component is enhanced and optimized, other spectral regions are underrepresented and then lead to color casts in the standard white light situation. The color cast can theoretically be corrected using filters, but that then also causes a reduction in intensity. On the other hand, true-color observation of a surgical field is important not least for diagnostic purposes. It is not possible to raise the intensity by way of an increase in lamp output, however, because of the limited aperture of the microscope&#39;s illumination optics as well as other effects. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the present invention to embody a microscope of the kind cited initially in such a way that an increase in illumination intensity is possible despite the limitation resulting from the aperture of the illumination optics. A further object of the invention is to improve white-light quality. 
     To achieve these objects, it is proposed according to the present invention that the optical device be equipped with at least one connector for a further illumination source. According to the present invention, therefore, at least one connector for a further illumination source is to be provided, it then being easily possible to optimize the one illumination source, having the predetermined spectral region, as a white-light source, and on the other hand to utilize the other source in optimized fashion with the spectral region that is specifically necessary and advisable for a particular application. It would in fact be conceivable to arrange multiple connectors for more than two illumination sources, which can be made effective using corresponding optical and/or electrical switching devices. 
     It is also possible in the context of the invention, however, to integrate the respective further illumination source into the microscope; the embodiment can be such that the microscope then contains the at least one further illumination device, and that this further illumination device possesses a spectral range differing from the predetermined spectral range. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further embodiments of the invention are evident from the symbolic and exemplifying description below with reference to the Figures, and from the dependent claims, the Parts List being a constituent of the disclosure. In the description, the Figures are described in continuous and overlapping fashion. Identical reference characters denote identical components; reference characters of different decades (10, 20, 30, etc.) indicate functionally identical or similar components. In the Figures: 
         FIG. 1  schematically depicts a microscope formed in accordance with a first embodiment of the present invention; 
         FIG. 2  schematically depicts a microscope formed in accordance with a second embodiment of the present invention; 
         FIG. 3  schematically depicts a microscope formed in accordance with a third embodiment of the present invention; and 
         FIG. 4  schematically depicts a microscope formed in accordance with a fourth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to  FIG. 1 , a specimen  1  is to be viewed by means of a microscope that possesses a schematically indicated microscope body  10  of a design known per se. Mounted in a fashion known per se on this microscope body  10  is an optical system for generating an observation beam path  11  along an optical axis  12 , which carries: a main objective  13  indicated simply as a lens; if applicable, two lenses or lens groups  14 ,  15  of a zoom optical system; a filter  18  that can be pivoted or slid as necessary into observation beam path  11  by means of an electromechanical motion device  17 , such as an electromagnet, an armature motor, or a similar motor (in the broadest sense); and, if applicable, an eyepiece (not depicted) at the top of observation beam path  11 . It is understood that in the case of a stereomicroscope, two such observation beam paths are provided. 
     To allow specimen  1  also to be appropriately illuminated, according to the present invention (at least) two light sources or illumination sources  20 ,  30  are provided which, via respective illumination beam paths  41 ,  51  and a deflecting mirror surface, preferably in the form of a mirror surface on respective illumination prisms  46 ,  56 , project respective illumination beam paths  45 ,  55  along associated optical axes  44 ,  54  onto specimen  1  that is to be observed. The invention makes it possible to adapt the illumination sources optimally to requirements. For white light, a xenon lamp may be used, for example, as light source  20 . A mercury vapor lamp will be advisable, for example as light source  30 , for light wavelengths in regions around  400  nm (blue light), and a wide variety of light sources, including in particular IR diode lasers, are possible for infrared. 
     Each of these illumination beam paths from light sources  20 ,  30  to specimen  1  encompasses a respective illuminating element  21 ,  31  that emits light (“light” being understood here as visible and invisible light, i.e. electromagnetic radiation in general) along optical axes  22 ,  32  via illumination optical systems  23 ,  33  to entrances  24 ,  34  of optical waveguides  25 ,  35  that direct the light to light exits  26 ,  36 . In the drawings, optical waveguides  25 ,  35  are depicted as being curved, i.e. as optical fiber bundles, but the invention is by no means limited thereto; the respective illumination source  20  or  30  could instead certainly also be mounted in such a way that its optical axis  22  or  32  coincides with an optical axis  42  or  52 , continuing on microscope body  10 , of a respective illumination beam path  41  or  51 . Other types of optical waveguides are also entirely conceivable and possible in the context of the invention, although the embodiment depicted, with optical waveguides  25 ,  35  or at least one of them, is preferred. It is usual, for example, for one standard illumination source  20  already to be installed in the stand of a surgical microscope. For second light source  30  provided according to the present invention, which if necessary can be present as an external unit, all that is inherently necessary is for light guide exit  36  to be configured as a connector for an optical waveguide  35  to be coupled on later. Connectors for optical waveguides are known per se, obviating the need for a detailed discussion here. This connector  36  is then advantageously mounted on a separate illumination module  40  that is attachable if necessary to an existing microscope and has the corresponding optical parts  43  and  46 . 
     As already indicated, exit sides  26 ,  36  of the respective optical waveguides  25 ,  35  lead directly to an optical system along optical axes  42  and  52  of illumination beam paths  41 ,  51 , on which axes respective illumination converging lenses  43 ,  53  are arranged. These converging lenses  43 ,  53  can of course be assembled from multiple individual lenses. 
     Lastly, the two optical axes  42 ,  52  encounter mirror prisms  46  and  56  and are then deflected into illumination beam paths  45 ,  55  (already mentioned) having optical axes  44  and  54 . These illumination beam paths  45 ,  55  are located close to observation beam path  11 , for which reason a blocking baffle plate  16  is advantageously provided between them. 
     In operation, one of the respective light sources  20 ,  30  is then switched on, for example via a switch  62  (manual or foot switch, keypad or voice control, etc.) connected to a control or monitoring unit  60  and via lines  63 ,  64 , in order to irradiate specimen  1  with, for example, white light or blue light. When a switchover to an excitation wavelength or spectrum needs to be made, filters  38 ,  58  for excitation, or filter  18  for observation, are then brought into the respective beam path  11 ,  41 , or  51 . Provided for this purpose are motion devices  37 ,  57  substantially similar to the one already described above with reference to device  17 . All these devices  17 ,  37 , and  57  are controlled by control device  60  and switch  62  via signal connection  61 ,  61 ′, usefully in such a way that the motion of excitation filters  38 ,  58 , but advantageously also that of observation filter  18 , occurs synchronously. This means that in excitation mode these filters are moved together into the respective beam path, and in white-light mode they are also moved synchronously out of the beam path. The control unit can contain, as hardware or software, a limit switch with acknowledgment that prevents the specimen from being unintentionally irradiated simultaneously with white light and excitation light. 
     What is depicted in  FIG. 1  as a single filter  38  can (and this applies also to the other filters  18  and  58 ) encompass multiple selectably insertable filters arranged one behind another. If light source  31  is a blue-light source, a first filter can then, for example, be embodied in such a way that it closes off the beam path along optical axis  32  when specimen  1  is being observed in white light, i.e. it acts as a shutter. Alternatively (or additionally, for selectable use), an illumination filter for the white-light mode is provided with which the spectrum of light source  31  is corrected. Lastly, an excitation filter can also be provided, which pivots or moves in only when exclusively the excitation wavelength is to be allowed to pass. The illumination energy of both light sources  21 ,  31  can then be available at the desired excitation wavelength (when filter  58  is pivoted or moved in) in the object field, so that the overall intensity is increased. Switch  62  can, however, also be used to switch off one of light sources  20  or  30  if additional light is not desired for an application. Filter changers having multiple filter sets can also be provided, in particular for multiple different (or even identical and synchronous) excitation and/or observation wavelengths, although the present invention also allows the provision of multiple connectors (cf. connector  36 ) for multiple light sources in different excitation spectral regions. 
     The exemplifying embodiment of  FIG. 2 , in which lines  61 ′,  63 , and  64  are not depicted, differs from that of  FIG. 1  substantially in that it omits excitation filter  58  ( FIG. 1 ) that may be pivoted or moved into illumination beam path  51  in microscope body  10 , and instead an excitation filter  28  is built into light source  20 , thereby avoiding or reducing electromechanical complexity in microscope body  10 . This is also preferred for physical reasons, especially since this embodiment has no disadvantageous effect of any kind on functionality. 
     The embodiment according to  FIG. 3  also differs from the previous exemplifying embodiments in terms of the accommodation of the filters. Here output line  61  of control unit  60  is connected to an electromechanical motion device or a central motor  67  in microscope body  10 , which motor displaces a filter set both in observation beam path  11  and in illumination beam paths  45 ,  55  in such a way that excitation filter  68   a  for first and second light sources  20 ,  30  in illumination beam paths  45 ,  55 , and observation filter  68   b  in observation beam path  11 , simultaneously become effective or are removed from those beam paths. This embodiment greatly reduces the outlay for electromagnetic motion devices, although the device must then be accommodated in microscope body  10 . Which of the embodiments is preferred, in particular which of the ones in  FIG. 2  and  FIG. 3 , will therefore depend on particular applications and physical circumstances. It should be mentioned, however, that a consequence of such an embodiment is that filter set  68 , and therefore also electromechanical motion device  67 , will need to be mounted relatively close to prisms  46  and  56 , since the expansion of the illuminating beam there is still relatively small. On the other hand, the expansion of observation beam path  11  is relatively large in this region, so a compromise must be struck. 
     The embodiment according to  FIG. 4  shows a combination of the embodiments of  FIG. 3  with those of  FIG. 1 . It thus allows different illumination or excitation filters  68 ,  58 , and/or  38  to be made effective as applicable, control device  60  being equipped for that purpose with corresponding control lines or signal buses  61 ,  61 ′. This embodiment can thus, of course, be used for a wide variety of applications. 
     Numerous variants are possible within the scope of the invention. For example, it is of course convenient if an individual electromechanical motion device (i.e. a “motor” in the broadest sense, meaning a “mover”) is provided for each of the respective filters  18 ,  28 ,  38 ,  58 ,  68  that is present, but simplified embodiments in which the filters (or one of them) are introduced manually into the respective beam path are of course by all means also within the scope of the invention. 
     The possible variations resulting from a combination of two regulatable illumination devices are what is critical in terms of the invention. Also within the scope of the invention, accordingly, is a variant configuration of a stereomicroscope that encompasses a conventional microscope illumination system plus the regulatable pair of illumination apparatuses according to the present invention. 
     PARTS LIST 
       1  Specimen 
       10  Microscope body 
       11  Observation beam path 
       12  Optical axis of  11   
       13  Main objective 
       14  Lens or lens group 
       15  Lens or lens group 
       16  Baffle plate 
       17  Electromechanical motion device 
       18  Filter 
       20  Light source  1 , illumination device 
       21  Illuminating element 
       22  Optical axis of light source 
       23  Illumination optical system 
       24  Optical waveguide entrance 
       25  Optical waveguide 
       26  Optical waveguide exit 
       27  Electromechanical motion device 
       28  Illumination/excitation filter 
       30  Light source  2   
       31  Illuminating element 
       32  Optical axis of light source 
       33  Illumination optical system 
       34  Optical waveguide entrance 
       35  Optical waveguide 
       36  Optical waveguide exit 
       37  Electromechanical motion device 
       38  Illumination/excitation filter 
       40  Illumination module 
       41  Illumination ray bundle 
       42  Optical axis of illumination beam path 
       43  Illumination converging lens 
       44  Optical axis of illumination field [sic] bundle 
       45  Illumination beam path 
       46  Illumination prism 
       51  Illumination beam path 
       52  Optical axis of illumination beam path 
       53  Illumination converging lens 
       54  Optical axis of illumination beam path  55   
       55  Illumination beam path 
       56  Illumination prism 
       57  Electromechanical motion device 
       58  Illumination/excitation filter 
       60  Control unit/monitoring device 
       61  Control signal/signal bus 
       62  Switch 
       63  Control signal/signal bus 
       64  Control signal/signal bus 
       67  Electromechanical motion device 
       68   a, b  Illumination and observation filters