Abstract:
An indexable microscope is described, that comprises a microscope stand and an optical beam path, having a plurality of optical components that are switchable into and out of the beam path, which are arranged on at least two independent mechanical assemblies to be indexed separately and are switchable selectably into and out of the beam path by indexing the respective assembly. According to the present invention, a space-saving and flexible arrangement of the separately indexable assemblies having the optical components is achieved in that a common central receiving plate is provided, on the upper side and the lower side of which at least one of the assemblies is respectively arranged. Configuration of the assemblies as rotary disks permits very flexible arrangements which allow both manual and motorized actuation of the indexing of the assemblies.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of the German patent application 10 2004 034 845.6-42 which is incorporated by reference herein. 
   FIELD OF THE INVENTION 
   The invention concerns an indexable microscope comprising a microscope stand and an optical beam path, having a plurality of optical components that are switchable into and out of the beam path, which are arranged on at least two independent mechanical assemblies to be indexed separately and are switchable selectably into and out of the beam path by indexing the respective assembly. 
   BACKGROUND OF THE INVENTION 
   Indexable microscopes, which comprise several optical components that can be switched into and out of the beam path, are known from a variety of microscopy application sectors. U.S. Pat. No. 5,633,752, for example, describes an incident-light fluorescence microscope having a special indexing apparatus for the fluorescence device. This microscope encompasses a disk-shaped base which is secured in the microscope housing and on which three rotary disks, mounted in coaxially rotatable fashion, are arranged one above another. Several absorption filters are arranged in different index positions on the first rotary disk, a corresponding number of excitation filters are arranged on the second rotary disk, and dichroic mirrors corresponding to the index positions are arranged on the third rotary disk. A respectively switched-in combination of absorption filter, excitation filter, and dichroic mirror constitutes a fluorescence device, which are usually combined into a fluorescence block. The resulting total height for the overall assemblage together with the baseplate is made up of the height of a usual fluorescence block plus, in addition, the thickness of the two rotary disks arranged thereabove. Because the baseplate at the same time is in contact at the bottom against the housing, the indexing apparatus cannot be supplemented with further elements. 
   German Unexamined Application DE 101 19 909 A1 also describes an indexable microscope having multiple indexable assemblies. Arranged on this are optical components that can be selectably inserted into the beam path. Various beam splitters or various tube lenses, for example, are arranged, as selectably insertable optical components, on the indexable assemblies. Because of the physical arrangement of the mechanical assemblies that are to be indexed separately, a considerable volume must be provided for installation of those assemblies in the microscope stand. 
   SUMMARY OF THE INVENTION 
   It is therefore the object of the present invention to describe a space-saving and flexible arrangement of separately indexable assemblies having optical components. 
   The mechanical assemblies comprise receptacles for several optical components, and can be embodied either as a sliding member or as a rotary disk. Rotary disks prove particularly advantageous in this context, since they can receive a greater number of optical components in a very small space. Rotary disks of different sizes, having parallel rotation axes offset with respect to one another, can be arranged on the upper side and the lower side of the central receiving plate. In such an arrangement, the respective upper and lower rotary disks can have different numbers of receptacles for the optical components. By indexing the assemblies from one position into the next, one of the optical components on the respective assembly can be selectably inserted into the beam path. The indexing can be accomplished, for example, by direct manual action, by the fact that the assembly is arranged in the microscope in externally accessible fashion. It proves advantageous, however, if respective actuation means, with which the assemblies can be indexed independently of one another, are associated with the assemblies. These actuation means can be embodied, for example, as friction wheels or toothed racks that are actuated manually by the user in order to achieve an indexing of the respective assemblies. Preferably, however, the actuation means are embodied as motorized drive systems that are electrically actuated. The actuation means for manual indexing, or the electric motors, are arranged either on the receiving plate or directly on the assemblies. 
   In an advantageous embodiment of the microscope, the optical components on the receptacles are aligned on the assemblies, and the assemblies on the central receiving plate, in such a way that upon indexing of the assemblies, the optical components are inserted into the beam path in precisely optically aligned fashion. 
   In a particularly advantageous embodiment of the microscope, the central receiving plate is equipped with high-precision stop surfaces. The microscope stand has corresponding high-precision countermembers for these stop surfaces. Upon installation of the central receiving plate into the microscope stand, the stop surfaces of the receiving plate are pushed against the countermembers of the microscope stand. As a result, all the assemblies arranged on the central receiving plate, and thus simultaneously all the optical components arranged thereon, are precisely mechanically and optically aligned in a single working step. Mounting of the central receiving plate can then be accomplished, for example, by the fact that it comprises mounting holes through which it is bolted onto the stand. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in more detail below with reference to examples and to the schematic drawings, in which: 
       FIG. 1   a  schematically shows the configuration of an indexable microscope in the form of an upright fluorescence microscope; 
       FIG. 1   b  schematically shows the configuration of an indexable microscope in the form of an inverted fluorescence microscope; 
       FIG. 2  is a side view of a central receiving plate having one assembly indexable in motorized fashion, and one indexable manually; 
       FIG. 3  is a plan view of the central receiving plate of  FIG. 2 ; 
       FIG. 4  is a side view of a central receiving plate having two assemblies that are indexable in motorized fashion; 
       FIG. 5  is a plan view of the central receiving plate of  FIG. 4 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1   a  schematically shows the configuration of an upright fluorescence microscope. An illumination beam path  2  proceeds from a light source  1  and strikes a fluorescence cube  3  arranged in the beam path of the microscope. This cube is arranged, along with a further fluorescence cube  4 , on a rotatable fluorescence assembly  5 . The latter is mounted rotatably about a rotation shaft  6 . This rotation shaft  6  is arranged fixedly on the lower side of a central receiving plate  7 . By rotation of fluorescence assembly  5  about rotation shaft  6 , one of fluorescence cubes  3  or  4  can be pivoted into the beam path of the microscope. In the present depiction, fluorescence assembly  5  comprises only two fluorescence cubes. Fluorescence assembly  5  can, however, be configured as a larger rotary disk so that it can accommodate substantially more fluorescence cubes. A quantity of up to eight fluorescence cubes has, for example, proven feasible in this context. 
   Illumination beam path  2  proceeding from light source  1  first passes through excitation filter  8  of fluorescence cube  3  and is then deflected by beam splitter  9  toward objective  10 . The light of illumination beam path  2  is imaged by objective  10  onto a specimen  11  that is resting on a microscope stage  12 . There the light is reflected from specimen  11 , traverses objective  10  again, passes through beam splitter  9 , and then travels through fluorescence barrier filter  13 . The light travels through opening  14  in central receiving plate  7  and then passes through tube lens  15 , which together with a second tube lens  16  is arranged above central receiving plate  7  in a displaceable assembly. This assembly, arranged on the upper side of central receiving plate  7 , is configured as a tube lens slider  17 . By displacement of tube lens slider  17 , either first tube lens  15  or second tube lens  16  can selectably be introduced into the beam path. The sliding motion of tube lens slider  17  is depicted in the Figure by a double arrow. After first tube lens  15 , the light reaches tube  18 . The image of specimen  11  can be viewed by a user of the microscope through eyepieces  19 . 
   Tube lenses  15  and  16  are arranged on the tube lens slider so that after the displacement of tube lens slider  17 , they are each aligned in optically exact fashion in the predefined positions in the beam path of the microscope. Fluorescence cubes  3  and  4  are likewise prealigned on the rotatable fluorescence assembly  5  so exactly that after fluorescence assembly  5  is pivoted into predefined positions, fluorescence cubes  3  and  4  are respectively aligned exactly in the beam path of the microscope. This alignment is guaranteed by the fact that the rotatable fluorescence assembly  5  is arranged on the lower side of central receiving plate  7 , and the displaceable tube lens assembly (in the form of tube lens slider  17 ) on the upper side of central receiving plate  7 , in precisely aligned fashion. In order to ensure optimal installation of central receiving plate  7  with the assemblies located thereon, central receiving plate  7  comprises several high-precision stop surfaces  20 . Embodied on the microscope stand (not depicted) are high-precision countermembers  21  against which stop surfaces  20  of central receiving plate  7  are pushed upon installation of central receiving plate  7 . Contact of stop surfaces  20  against countermembers  21  thus ensures that simultaneously, in a single working step, all the assemblies and therefore all the optical components arranged thereon—i.e. in this case tube lenses  15  and  16  as well as fluorescence cubes  3  and  4 —are precisely mechanically and optically aligned. This is advantageous both during manufacture and in the event of a service operation. 
   The present invention has been depicted with reference to  FIG. 1   a  using the example of an upright fluorescence microscope. It is clear to one skilled in the art that the invention can also be integrated, in entirely analogous fashion, into an inverted microscope. Such an inverted microscope is shown in  FIG. 1   b.  It comprises substantially the same components as in  FIG. 1   a,  with the addition only of two beam deflection means  40 . Identical components are always identified with the same reference numbers. For example, here a fluorescence assembly  5  is arranged on the upper side of the common central receiving plate  7 , and the displaceable tube lens assembly (in the form of a tube lens slider  17 ) on the lower side of central receiving plate  7 . 
   The optical components on the assemblies to be indexed can be very different depending on the application. For example, in addition to the fluorescence cubes and tube lenses and tube-lens systems already described, color filters, modulators such as Hoffmann modulators, side ports out of the beam path, broad-band protection filters for the infrared or ultraviolet radiation region, light stops (“shutters”), mirror scanners, etc., can be arranged on the indexable assemblies. It is even conceivable in this context for optical components of completely different functionality to be arranged on one indexable assembly. Because the assembly or assemblies on the upper side and on the lower side of the common central receiving plate are switchable independently of one another, it is thereby possible to introduce into the beam path any desired combinations of optical components that the user may consider necessary for a particular application. 
   Because of the arrangement of the indexable assemblies on the upper side and lower side of the central receiving plate, there is no absolute necessity to select assemblies, e.g. rotary disks, having the same size and the same number of optical components. Instead, the combination of the upper and lower assembly can be selected entirely without restriction. For example, an indexable assembly arranged on the upper side of the central receiving plate can have eight receptacles for eight optical components, one of which is to be introduced respectively into the beam path of the microscope. The assembly that is arranged on the lower side of the central receiving plate can have, for example, only two or three receptacles for two or three optical components, respectively. If one position on the assemblies is left unoccupied or cannot be occupied, this then serves as an open passage with no optical component. Two additional examples of possible configurations will be described with reference to the Figures described below. 
     FIG. 2  is a sectioned view of a central receiving plate  7  having an opening  14 . The exact arrangement is evident from  FIG. 3 , which is a view from above of central receiving plate  7  with the assemblies of  FIG. 2  located on it. The line labeled AB in  FIG. 3  indicates the section line shown in the sectioned view of  FIG. 2 . 
   Arranged on the lower side of central receiving plate  7  is a rotatable tube lens assembly  25  embodied as a rotary disk. A tube lens  22 , here clearly recognizable as an entire lens system, is pivoted into the beam path of the microscope (not depicted here). The beam path is represented schematically by an optical axis  23 . In this view, rotation axis  24  of rotatable tube lens assembly  25  aligns with optical axis  23  and is located, in this depiction, in front of the section plane. The arrangement of optical axis  23  and rotation axis  24  of rotatable tube lens assembly  25  is evident from  FIG. 3 . In  FIG. 3 , tube lens  22  is concealed by central receiving plate  7 . 
   In this position pivoted into the beam path, tube lens  22  is aligned on optical axis  23  and is arranged directly beneath an opening  14  in central receiving plate  7 . As is apparent from both  FIG. 2  and  FIG. 3 , in the example depicted here, in order to make the drawing clearer, no further tube lenses are arranged on rotatable tube lens assembly  25 . Arranged on the upper side of central receiving plate  7  is a rotatable fluorescence assembly  26  embodied as a rotatable disk. It comprises several receptacles  27  onto which fluorescence cubes can be mounted. For example, a fluorescence cube  28  having an excitation filter  29 , a beam splitter  30 , and a barrier filter  31  is mounted on receptacle  27  depicted to the right in  FIG. 2 . 
   Fluorescence assembly  26  is mounted rotatably about a rotation axis  32 . As is apparent from  FIG. 3 , fluorescence assembly  26  comprises six receptacles  27  for fluorescence cubes. As depicted here, fluorescence assembly  26  is rotated into a position such that fluorescence cube  28  is arranged in the beam path of the microscope, i.e. centered on the optical axis. Fluorescence cube  28 , as well as unoccupied opening  14  of central receiving plate and tube lens  22 , are thus arranged one above another and positioned on optical axis  23 . 
   Rotation axis  32  of fluorescence assembly  26  is located on center line AB of central receiving plate  7 . Arranged at the edge of the rotary disk of fluorescence assembly  26  is a ring gear  33  into which pinion  34  on the shaft of motor  35  engages. Fluorescence assembly  26  can thus be shifted into any desired positions by appropriate electrical activation of motor  35 , so that the fluorescence cubes mounted on receptacles  27  can be arranged centeredly on optical axis  23 . 
   Rotation axis  24  of tube lens assembly  25  is arranged at a distance from center line AB of central receiving plate  7 . The edge of the rotary disk of tube lens assembly  25  thus protrudes for some distance beneath central receiving plate  7 . Microscope housing  36  has a housing opening  37  through which a microscope user can reach the edge of the rotary disk of tube lens assembly with his or her hand, and thereby bring about manual displacement of tube lens assembly  25 . 
   In  FIG. 3 , central receiving plate  7  comprises mounting holes  38  with which it can be bolted onto the microscope stand (not depicted). To allow exact alignment and positioning of central receiving plate  7  and thus of the optical components in the beam path of the microscope, central receiving plate  7  comprises stop surfaces  39  machined with high precision which are pushed against countermembers (not depicted here) on the microscope stand, as already explained with reference to  FIG. 1   a.    
     FIGS. 4 and 5  show a further exemplifying embodiment of the present invention in which all the assemblies are operated in motorized fashion, as will be explained below. Arranged on a central receiving plate  7  having an opening  14  are, on its lower side, a tube lens assembly  25  embodied as a rotary disk and, on its upper side, a fluorescence assembly  26  embodied as a rotary disk. Tube lens assembly  25  is mounted rotatably about a rotation axis  24 . Fluorescence assembly  26  is likewise mounted rotatably about a rotation axis  32 . Fluorescence assembly  26  is pivoted into a position such that a fluorescence cube  28  attached to its receptacle  27  is arranged in aligned fashion in the region of optical axis  23 . Optical axis  23  proceeds centrally through opening  14  of central receiving plate  7 . Tube lens assembly  25  is rotated into a position such that a tube  22  is likewise aligned on optical axis  23 . 
   Rotation axis  24  of tube lens assembly  25  and rotation axis  32  of fluorescence assembly  26  are located, together with optical axis  23 , on center line AB of central receiving plate  7 . A very compact configuration for the entire unit comprising central receiving plate  7 , tube lens assembly  25 , and fluorescence assembly  26  is thereby achieved. This refers both to the width of the entire arrangement in plan view as shown in  FIG. 5 , and to the height of the assemblage as shown in  FIG. 4 . Tube lens assembly  25  and fluorescence assembly  26  are displaced in motorized fashion. For that purpose, the rotary disks of tube lens assembly  25  and of fluorescence assembly  26  each have a ring gear  33  at their outer edge. Associated with both tube lens assembly  25  and fluorescence assembly  26  is a respective motor  35  on whose shaft is mounted a pinion  34  that engages into the respective ring gear  33  of the associated assembly. As a result of the rotation of pinion  34  on the motor, both tube lens assembly  25  and fluorescence assembly  26  can thus be rotated into the desired position. The arrangement of displaceable assemblies on the upper side and the lower side of a central receiving plate  7  thus allows a very compact configuration to be achieved, requiring little installation space even when the assemblies are driven in completely motorized fashion. 
   In  FIG. 5  as well, mounting holes  38  are provided on central receiving plate  7  and allow it to be bolted to the microscope stand (not depicted). To allow exact alignment and positioning of central receiving plate  7  and thus of the optical components in the beam path of the microscope, high-precision stop surfaces  39  are provided on central receiving plate  7  and are pushed against countermembers (not depicted here) on the microscope stand, as already explained with reference to  FIG. 1   a . 
   
     
       
             
           
             
             
           
         
             
                 
             
             
               PARTS LIST 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               1 
               Light source 
             
             
               2 
               Illumination beam path 
             
             
               3 
               First fluorescence cube 
             
             
               4 
               Second fluorescence cube 
             
             
               5 
               Rotatable fluorescence assembly 
             
             
               6 
               Rotation axis 
             
             
               7 
               Central receiving plate 
             
             
               8 
               Excitation filter 
             
             
               9 
               Beam splitter 
             
             
               10 
               Objective 
             
             
               11 
               Specimen 
             
             
               12 
               Microscope stage 
             
             
               13 
               Fluorescence barrier filter 
             
             
               14 
               Opening 
             
             
               15 
               First tube lens 
             
             
               16 
               Second tube lens 
             
             
               17 
               Tube lens slider 
             
             
               18 
               Tube 
             
             
               19 
               Eyepieces 
             
             
               20 
               Stop surfaces 
             
             
               21 
               Countermembers 
             
             
               22 
               Tube lens 
             
             
               23 
               Optical axis 
             
             
               24 
               Rotation axis of 25 
             
             
               25 
               Tube lens assembly 
             
             
               26 
               Fluorescence assembly 
             
             
               27 
               Receptacles 
             
             
               28 
               Fluorescence cube 
             
             
               29 
               Excitation filter 
             
             
               30 
               Beam splitter 
             
             
               31 
               Barrier filter 
             
             
               32 
               Rotation axis of 26 
             
             
               33 
               Ring gear 
             
             
               34 
               Pinion 
             
             
               35 
               Motor 
             
             
               36 
               Microscope housing 
             
             
               37 
               Housing opening 
             
             
               38 
               Mounting holes 
             
             
               39 
               Stop surfaces 
             
             
               40 
               Beam deflection means