Abstract:
The present invention concerns a microscope  1 . The microscope  1  encompasses a microscope stand  2 , an objective  4  having an optical axis  5 , a microscope stage  6  serving to receive a specimen  7 , and a focusing device  20  serving to focus the specimen  7 . With the focusing device  20 , the objective or the microscope stage  6  is positionable relative to the microscope stand  2  in the direction of the optical axis  5  of the objective  4 . The focusing device  20  comprises at least one operating element  8  with which an operator controls the positioning of the objective  4  or of the microscope stage  6 . For adaptation of the spatial arrangement of the operating element  8  to the needs of an operator, the microscope  1  according to the present invention is characterized in that the spatial arrangement of the operating element  8  relative to the microscope stand  2  is modifiable.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority of German patent application 103 40 721.9, filed Sep. 4, 2003, which is incorporated by reference herein.  
       FIELD OF THE INVENTION  
       [0002]     The present invention concerns a microscope.  
       BACKGROUND OF THE INVENTION  
       [0003]     Microscopes of the kind cited above have been known for some time in the existing art. Very generally, in upright and inverted light microscopes, focusing of the specimen is accomplished by way of a corresponding positioning of the specimen relative to the objective, specifically in such a way that a specimen region to be detected is arranged in the focal plane of the objective. This can be achieved on the one hand by the fact that the objective, optionally together with the objective turret receiving the objective, is positioned along the optical axis relative to the specimen. In this case the specimen, for example mounted on a conventional specimen slide, is clamped in a corresponding holder on the microscope stage, this microscope stage then not being moved in the direction of the optical axis of the microscope objective. This type of focusing is usually utilized with inverted light microscopes. On the other hand, the microscope stage can be arranged movably relative to the microscope stand, and positioned in the direction of the optical axis for focusing. In this case the objective does not perform a motion in the direction of its optical axis relative to the microscope stand. The latter type of focusing is usually utilized with upright light microscopes. Focusing with the aid of the microscope stage also exists, for purposes of the present invention, when the microscope stage comprises a mechanism with which a specimen slide performs a positioning relative to the objective with the aid of a linear or pivoting motion controlled by a galvanometer, as is the case, for example, with the assignee&#39;s confocal laser scanning microscopes.  
         [0004]     In both cases, a focusing of the specimen to be investigated is usually performed by the fact that an operator operates an operating element arranged on the microscope stand, as a result of which either the objective or the microscope stage is positioned, as a function of the operator&#39;s operation, relative to the microscope stand in the direction of the optical axis of the objective. The operating element is a rotary knob, but usually two rotary knobs (one rotary knob for fine drive and one rotary knob for coarse drive) which are arranged rotatably about a rotation axis and are directly or indirectly coupled to a shaft. Rotation of the rotary knob by the operator causes rotation of the shaft coupled to the operating element. The rotation of the shaft is in turn transferred, usually in mechanical fashion, into a linear motion of the microscope stage or the objective in the direction of the optical axis.  
         [0005]     The operating element is usually arranged laterally at a certain height on one side wall of the microscope stand, usually a few centimeters away from a support surface on which the microscope stands. This arrangement of the operating element is optimized for an average operator&#39;s hand size, but it is arranged too low for operators with large hands, and too high for operators with small hands. For users with a hand size deviating from the average hand size, microscope operation is therefore fatiguing over the long term and as a result, not ergonomic in that respect.  
       SUMMARY OF THE INVENTION  
       [0006]     It is therefore the object of the present invention to describe and refine a microscope of the kind cited initially with which the aforementioned problems are eliminated. In particular, the arrangement of the operating element is intended to be adaptable to an operator&#39;s needs, so that ergonomic microscope operation is additionally possible for operators irrespective of their hand size.  
         [0007]     The above object is achieved by a microscope, a microscope stand; a microscope stage; at least one objective that, in a working position, defines an optical axis; a focusing device having at least one operating element that is provided on the microscope stand, wherein the operating element generates a relative motion between the objective and the microscope stage in the direction of the optical axis and the operating element sits on a first shaft of the focusing device and a side wall is defined by the microscope, wherein the focusing device is modifiable in terms of its position within the microscope stand in such a way that the spatial arrangement of the at least one operating element on the side wall of the microscope stand is adjustable.  
         [0008]     What has been recognized according to the present invention is that for different operators with different hand sizes, microscope operation can be performed, in particular in ergonomic and efficient fashion over longer periods of time, when the arrangement or position of the operating element on the microscope stand can be modified. A microscope operator with a small hand size thus need not assist himself by, for example, placing alongside the microscope stand a book on which he then rests his hand for operation of the operating element and thereby decreases the distance between the operating element and the support surface on which the microscope stands. With an arrangement of the operating element on the microscope stand that is modifiable according to the present invention, the position of the operating element is individually adaptable to an operator&#39;s needs, the very particularly advantageous result being that fatigue of the user&#39;s arm or hand when operating the microscope can be largely prevented, at least with regard to focusing.  
         [0009]     It is conceivable in principle that the operating element can be capable of being modified relative to the microscope stand in the horizontal and/or vertical direction relative to a support surface on which the microscope is arranged. Specifically when an operator has a short arm length, it may be advantageous to modify the arrangement of the operating element in the horizontal direction in such a way that he “brings the operating element closer” to himself.  
         [0010]     Provision is preferably made, however, for the spatial arrangement of the operating element to be modifiable substantially in the vertical direction. A support carriage, with which the operating element is associated and which is movable along a guide provided on the microscope stand, could be provided for that purpose. The guide can be embodied in such a way that the operating element is adjustable on the microscope stand substantially in a direction parallel to the optical axis. In another embodiment, the spatial arrangement of the at least one operating element on at least one side wall of the microscope stand is adjustable substantially in the vertical and horizontal direction by means of a curved elongated hole.  
         [0011]     The support carriage and the associated focus device are usually arranged in the interior of the microscope stand and are thus not visible to the operator. Concretely, an “association” of the operating element with the support carriage is to be understood to mean that the operating element is arranged non-modifiably in terms of its spatial arrangement relative to the support carriage. In this case, the spatial arrangement of the operating element with respect to the microscope stand could thus be varied in the vertical direction by way of a displacement of the support carriage or of the focus device.  
         [0012]     The guide for the support carriage could comprise a ball guide, in particular a crossed roller guide, or a plain guide, in particular a dovetail guide. The support carriage could in that respect be mounted or guided in a manner comparable to an objective turret or microscope stage, those assemblies also being arranged displaceably in the direction of the optical axis of an objective.  
         [0013]     Very generally, the operating element of the focusing device could comprise at least one pushbutton switch with which the objective or the microscope stage can be positioned. This is the case especially for microscope stands of research microscopes, in which motion of the objective or of the microscope stage is accomplished in motor-controlled fashion. The operating elements configured in the form of pushbutton switches are accordingly embodied as transducers for a control device having a corresponding motor. The microscope is then embodied in such a way that the first shaft of the focusing device is equipped with a coding disk that coacts with a sensor element which converts into electrical signals the rotation of the first shaft generated by the operating element. The sensor element is, for example, a light barrier that is immovably connected to the focusing device. At least one motor that effects the relative motion between the objective and microscope stage is provided in the interior of the microscope stand. For the activation thereof, the motor receives the signals generated by the sensor element.  
         [0014]     With simple microscope stands in particular, however, the operating element comprises for focusing at least one rotary knob (operating element), mounted rotatably about a rotation axis, with which focusing is implemented in purely mechanical fashion. This type of focusing has become established not only because of its intuitive operation, and is also used in high-priced microscope stands, if applicable in addition to pushbuttons. In a preferred exemplary embodiment, therefore, the operating element is arranged rotatably about a rotation axis. It is preferably coupled to a shaft that is rotatable as a result of the rotation of the operating element. A configuration of this kind is, considered of itself, known from the existing art.  
         [0015]     According to a very particularly preferred embodiment, the operating element is associated with a focus device, the focus device and thus also the operating element being arranged pivotably about a pivot axis. The focus device could be arranged on a support carriage that can be moved substantially in the vertical direction. As a result of this, the spatial arrangement of the operating element relative to the microscope stand could be modified by way of an upward or downward motion of the entire support carriage. On the other hand, given a specific position of the operating element associated with the focus device, the operating element could be pivoted about the pivot axis that is provided, so that horizontal and vertical modifications of the arrangement of the operating element relative to the microscope stand can thus be accomplished simultaneously. Preferably, however, provision is made for providing only a pivoting of the operating element about a pivot axis, the pivot axis being arranged on the microscope stand. The arrangement of the pivot axis on the microscope stand, the spacing between the operating element and the pivot axis, and the definition of the pivot angle range, enable a modification of the spatial arrangement of the operating element on the microscope stand in such a way that motions of the operating element relative to the microscope stand that have substantially a vertical and a horizontal directional component are possible. In particularly advantageous fashion, this embodiment can be embodied relatively easily in terms of design, so that the manufacturing costs therefor can be kept low.  
         [0016]     For pivotable arrangement of the operating element, a focusing device could be provided which is arranged pivotably about the pivot axis and with which the operating element is associated. The focus device is preferably arranged in the interior of the microscope stand and in a manner not visible to an operator.  
         [0017]     In principle, an operator manipulation of the operating element could be transferred mechanically or in another fashion for generation of a relative motion between the microscope stage and the objective. If the operating element comprises only an electrical transducer, an obvious choice is to transfer the signals generated by the transducer in electrical fashion, for example via a flexible cable connection, and to use them to generate a relative motion between the microscope stage and the objective. A rotatably mounted second shaft arranged substantially coaxially with respect to the pivot axis of the focusing device could be provided, in particular, for mechanical transfer of an operator manipulation of the operating element. The shaft could be embodied in such a way that a rotary motion of a shaft of the operating element is transferable to the second shaft, a prerequisite for this approach being that the operating element be rotatable about a rotation axis and be coupled to a shaft that is rotatable by rotation of the operating element.  
         [0018]     In the context of a mechanical transfer of the manipulation of the operating element to the focusing device, provision is preferably made for transferring the rotary motion between the shaft of the operating element and the second shaft in positively engaged fashion. This could be effected, in particular, using at least two gears, one gear preferably being arranged nonrotatably on each shaft and the gears being in meshing engagement with one another. Teeth could also be provided on one shaft in at least one region, so that no gear need be provided on that shaft.  
         [0019]     In the context of a pivotably mounted focus device, the rotary motion of the second shaft could be transferable in positively engaged fashion to a mechanism that moves the objective or the microscope stage relative to the microscope stand in the direction of the optical axis of the objective. A “positively engaged transfer” is to be understood in particular as the meshing engagement of at least two components configured in complementary fashion to one another. The two components could, for example, comprise two gears or a gear and a toothed rack.  
         [0020]     For the case in which only a relative motion of the focus device (and thus of the operating element) with respect to the microscope stand in the vertical direction is accomplished, the rotary motion of a rotation axis of the operating element associated with the support carriage could be transferable in positively engaged fashion to a mechanism. That mechanism then once again moves the objective or the microscope stage relative to the microscope stand in the direction of the optical axis of the objective.  
         [0021]     Very generally, at least one further intermediate shaft could be provided that serves for positively engaged transfer of the rotary motion of a shaft of the operating element to a mechanism that moves the objective or the microscope stage relative to the microscope stand in the direction of the optical axis of the objective. Corresponding step-down or step-up conversions of the rotary motion of the shaft of the operating element to the mechanism can thereby be attained, for example by way of a suitable selection of different gear diameters. This enables on the one hand rapid positioning of the objective or of the microscope stage along an entire positioning range, and on the other hand sufficient fine positioning of the objective or the microscope stage, so that a specific specimen region can be focused in controlled fashion and with sufficient resolution in terms of positioning motion.  
         [0022]     Concretely, the mechanism for moving the objective or the microscope stage relative to the microscope stand in the direction of the optical axis of the objective could comprise a toothed rack. In this case the toothed rack is in meshing engagement with the second shaft or with a rotation axis of the operating element associated with the support carriage. Since the microscope stage or the microscope objective must be moved, for focusing, in the direction of the optical axis of the microscope objective, and that axis is usually oriented vertically, an obvious choice is also to align the toothed rack with its longitudinal axis vertical, so that the rotary motion of a shaft in meshing engagement with the toothed rack is converted directly into a linear motion in the vertical direction.  
         [0023]     Once the operating element has then been arranged by an operator, in operator-specific fashion, in its spatial positions relative to the microscope stand, provision must be made for immobilizing the operating element in a specific position selected by the operator. Means with which the support carriage or the focus device can be immobilized on the microscope stand are provided for that purpose. This immobilization is preferably accomplished nonpositively, for example by wedging a part of the operating element with respect to the microscope stand.  
         [0024]     In very particularly preferred fashion, the at least one operating element comprises a coarse drive and/or a fine drive. It is thus possible for a microscope operator to adjust the microscope stage or the objective, in a familiar manner, over a larger displacement range using the coarse drive and/or over a small displacement range using the fine drive. The coarse drive or fine drive can be embodied, in a manner known from the existing art, in motorized or mechanical fashion, a mechanical embodiment preferably being achievable by way of a recirculating ball drive system.  
         [0025]     For a motorized embodiment of the focusing device, at least one motor could be provided with which a shaft of the focusing device is rotatable or drivable. A shaft associated with the operating element could preferably be rotated by the motor. The motor could comprise a stepping motor and, if applicable, a step-down gear drive.  
         [0026]     In a preferred embodiment, a guide, on which the microscope stage or an objective turret receiving the objective is movable, is provided on the microscope stand. This guide could be a ball guide, in particular a crossed roller guide, or a plain guide, in particular a dovetail guide. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]     There are various ways of advantageously embodying and refining the teaching of the present invention. In conjunction with the explanation of the preferred exemplary embodiments of the invention with reference to the drawings, an explanation is also given of generally preferred embodiments and refinements of the teaching. In the drawings:  
         [0028]      FIG. 1  is a side view of a microscope in which the teaching of the present invention is implemented;  
         [0029]      FIG. 2  is a perspective view of the microscope, in which several elements are removed so as to obtain a better impression of the microscope stand;  
         [0030]      FIG. 3  is a perspective view of the microscope from the front;  
         [0031]      FIG. 4  is a three-dimensional view of a microscope stand according to the present invention from below, looking into the interior of the microscope stand;  
         [0032]      FIG. 5  is a three-dimensional view of an exemplary embodiment of a focusing device in accordance with an exemplary embodiment of the microscope according to the present invention;  
         [0033]      FIG. 6  is a detail view of the focus device along section line F-F of  FIG. 1 ;  
         [0034]      FIG. 7  is a sectioned view of a first exemplary embodiment of the present invention, only a vertical displacement of the focus device being possible;  
         [0035]      FIG. 8  is a sectioned view of a second exemplary embodiment of the present invention, a displacement of the focus device with a horizontal and a vertical component being possible; and  
         [0036]      FIG. 9  is a sectioned view of a further embodiment of the invention in which an electronic coding of the rotary motion of the operating elements of the microscope is performed. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]      FIG. 1  is a side view of a microscope  1  in which the teaching of the present invention is implemented. Microscope  1  encompasses a microscope stand  2 . Microscope  1  stands on a support surface  10 . Also provided on microscope stand  2  is a turret  3  that carries at least one objective  4 . Objective  4  can be pivoted by means of turret  3  into a working position. Objective  4  possesses an optical axis  5  that, in the working position of objective  4 , runs perpendicular to a microscope stage  6 . A specimen  7  to be investigated can be placed on microscope stage  6 . Microscope  1  comprises a focusing device  20  (see  FIG. 5 ) serving to focus specimen  7 , focusing device  20  being installed in the interior of microscope stand  2 . With this focusing device  20 , microscope stage  6  is positionable relative to microscope stand  2  in the direction of optical axis  5  of objective  4 . Focusing device  20  carries two operating elements  8  (only one operating element  8  is depicted in the side view of  FIG. 1 ). Operating elements  8  are provided on the two side walls  2   a  and  2   b  of microscope stand  2 . With these operating elements  8 , a user can enable the displacement of microscope stage  6  in the direction of optical axis  5 . The displacement of microscope stage  6  results in a focusing of specimen  7  present on microscope stage  6 . A displacement element  9  for microscope stage  6  is positioned directly in front of operating element  8 . Displacement element  9  is connected to microscope stage  6  and enables a displacement of microscope stage  6  perpendicular to optical axis  5 , by which means specimen  7  can be positioned in the image field of objective  4 . Displacement element  9  encompasses an X element  9   a  that enables displacement of microscope stage  6  in the X direction. Displacement element  9  further encompasses a Y element  9   b  that enables displacement of microscope stage  6  in the Y direction.  
         [0038]      FIG. 2  is a perspective view of microscope  1  in which some elements are removed in order to obtain a better impression of microscope stand  2  and its configuration. Microscope stand  2  possesses a flange  11 , e.g. for attaching a binocular eyepiece (not depicted). This is not, however, to be construed in any way as a limitation. Microscope stand  2  further comprises a holding element  12  for microscope stage  6  (see  FIG. 1 ). Holding element  12  is movable by focus device  20  parallel to optical axis  5  of objective  4  that is located in the working position. Focusing device  20  installed in the interior of microscope stand  2  possesses a first end  14   a  and a second end  14   b  (see  FIG. 5 ). First end  14   a  and second end  14   b  engage through an opening  15  on first and on second side wall  2   a  and  2   b , respectively, of microscope stand  2 . As already explained in the description relating to  FIG. 1 , an operating element  8  can be attached respectively onto first and second ends  14   a  and  14   b  of focusing device  20 . In the exemplary embodiment depicted in  FIG. 2 , opening  15  possesses the shape of a curved elongated hole  13  that is embodied on the oppositely located side walls  2   a  and  2   b  of microscope stand  2 . In the embodiment depicted in  FIG. 7 , focusing device  20  installed in the interior of microscope stand  2  likewise engages with first end  14   a  and with second end  14   b  (see  FIG. 5 ) through opening  15  on first and on second side wall  2   a  and  2   b , respectively, of microscope stand  2 . In this embodiment, opening  15  is configured as longitudinal opening  51  in first and in second side wall  2   a  and  2   b.    
         [0039]      FIG. 3  is a perspective view of microscope  1  from the front. In the interior, microscope  2  is constructed in part from multiple struts  16 . This results on the one hand in a savings of material, and on the other hand in a stiffening of microscope stand  2 . Several installation positions  17  are likewise configured in the interior of holding element  12  of microscope stage  2 . Each of installation positions  17  comprises a first stop surface  17   a  and a second stop surface  17   b . First and second stop surface  17   a  and  17   b  run perpendicular to one another and are configured in such a way that a component (not depicted) to be attached at that position can be attached with screws in the position without further alignment. In  FIG. 3 , second end  14   b  of focusing device  20  provided in the interior of microscope stand  2  is visible on second side wall  2   b . A rotation axis  18  of focusing device  20  is likewise accessible via first and second side wall  2   a  and  2   b.    
         [0040]      FIG. 4  is a three-dimensional view from below microscope stand  2  according to the present invention, and thus offers a view into interior  2   c  of microscope stand  2 . Focusing device  20  shown in  FIG. 5  can be immobilized in interior  2   c  of microscope stand  2 . For that purpose, the two ends  14   a  and  14   b  of focusing device  20  project out beyond the two side walls  2   a  and  2   b  of microscope stand  2  (see  FIG. 2 ). Focusing device  20  encompasses one of several gears  22 . One of the gears  22  of focusing device  20  is in meshing engagement with a mechanism  24  that transfers the rotary motion of one of the gears in positively engaged fashion to mechanism  24 , which moves microscope stage  3  relative to microscope stand  2  in the direction of optical axis  5  of an objective  4 .  
         [0041]      FIG. 5  is a three-dimensional view of an exemplary embodiment of focusing device  20  in accordance with an exemplary embodiment of microscope  1  according to the present invention. According to this exemplary embodiment, focusing device  20  possesses a pivot axis  23  about which focusing device  20  is pivotably arranged. Pivot axis  23  is mounted pivotably on microscope stand  2  or in interior  2   c  of microscope stand  2 .  
         [0042]     Focusing device  20  encompasses two elongated orifices  25  through which can be introduced a pin or a second shaft (not shown in  FIG. 5 ) with which focusing device  20  can be pivotably mounted on microscope stand  2 . Pivot axis  23  of focusing device  20  of  FIG. 5  accordingly extends centeredly through the two orifices  25 , this being indicated in  FIG. 5  with dashed lines. These orifices  25  carry a second shaft  21 . Focusing device  20  possesses a further, first shaft  26  that is arranged parallel to pivot axis  23 . First shaft  26  is arranged rotatably about an axis  27  and comprises first end  14   a  and second end  14   b  to which operating elements  8  for focusing device  20  are attached. Rotary motion is transferable between first shaft  26 , focusing device  20 , and second shaft  21  in positively engaged fashion. A gear  22  arranged nonrotatably on second shaft  26  is provided for that purpose. Teeth  21   a  that are in meshing engagement with the teeth of gear  22  are configured in a central region of first shaft  26 .  
         [0043]     The rotary motion of second shaft  21  is transferable in positively engaged fashion to mechanism  24  (see  FIG. 4 ), which moves microscope stage  6  relative to microscope stand  2  in the direction of optical axis  5  of an objective  4 . A second gear  28 , joined nonrotatably to second shaft  21 , is provided for that purpose on second shaft  21 . Second gear  28  is in meshing engagement with toothed rack  30 , which represents a part of mechanism  24  with which microscope stage  3  is movable relative to microscope stand  2  in the direction of optical axis  5  of an objective  4 . Focusing device  20  is equipped on one side with a flange  32  with which focus device  20  is immobilized on or pressed against a side wall  2   a  or  2   b  of microscope stand  2 . A clamping immobilization of focus device  20  on microscope stand  2  thus occurs.  
         [0044]      FIG. 6  is a detail view of focus device  20  along section line F-F of  FIG. 1 .  FIG. 3  shows that operating elements  8  comprise a coarse drive  8   a  and a fine drive  8   b . Coarse drive  8   a  of operating element  8  is operable by the operator via rotary knobs  35 . Rotary knobs  35  of coarse drive  8   a  are nonrotatably connected to first shaft  26 , so that a rotation of rotary knob  35  directly brings about rotation of first shaft  26 . Two rotary knobs  35  are provided for coarse drive  8   a , namely one on left side wall  2   a  and another on right side wall  2   b  of microscope stand  2 . First shaft  26  associated with focus device  20  correspondingly extends transversely through interior  2   c  of microscope stand  2 . At least one further rotary knob  36  that is arranged nonrotatably on a shaft  40  is additionally provided. Rotation of rotary knob  36  causes rotation of shaft  40  which, as a result of a nonpositive connection, rotates a ball  38  of a recirculating ball drive  39 . This in turn transfers its rotation to first shaft  26  of operating element  8 . Because of the step-down conversion ratio between shaft  40 , ball  38 , and housing  34  (see  FIG. 4 ) of recirculating ball drive  39 , shaft  26  is rotated with a large step-down ratio upon actuation of rotary knob  36 , ultimately enabling fine positioning of specimen  7  relative to objective  4 .  
         [0045]     In  FIG. 7 , focus device  20  is immobilized on a support carriage  41  as shown, and not on microscope stand  2 . Downward motion of support carriage  41  is prevented by a spring  42  arranged on microscope stand  2 . Shaft  21  mounted on support carriage  41  can project laterally out of microscope stand  2  through elongated opening or hole  13  indicated with dashed lines in  FIG. 8 . In the second exemplary embodiment, opening  15  provided in microscope stand  2  is embodied in the form of a circle segment or as curved elongated hole  13 , the circle-segment shape being adapted to the distance between axis  27  of focus device  20  and axis  9  or first shaft  26  of operating element  8 .  
         [0046]     According to the exemplary embodiment of  FIG. 7 , the rotary motion of shaft  26 , associated with support carriage  41 , of operating element  8  is transferable in positively engaged fashion to mechanism  24  that moves microscope stage  6  relative to microscope stand  2  in the direction of optical axis  5  of objective  4 . For positively engaged energy transfer, at least one further intermediate shaft  19  (see also  FIG. 8 ) can be provided that serves for positively engaged transfer of the rotary motion of first shaft  26  to mechanism  24  that generates the relative motion between objective  4  and microscope stage  6  in the direction of optical axis  5  of objective  4 . According to this exemplary embodiment, shaft  26  of operating element  8  that is in meshing engagement with gear  22  is embodied on support carriage  41  in rotatably mounted fashion, gear  22  being mounted nonrotatably on second shaft  21 . Second shaft  21  is likewise rotatably mounted on support carriage  41 . Second shaft  21  thus has the function of a further intermediate shaft that serves for positively engaged transfer of the rotary motion of first shaft  26  of operating element  8  to mechanism  24  that moves microscope stage  6  relative to microscope stand  2  in the direction of optical axis  5  of objective  4 . The rotary motion of operating element  8  would thus (leaving aside the attainment of a predefined step-down conversion ratio) likewise be transferable directly from first shaft  26  to toothed rack  44  of mechanism  24 .  
         [0047]     According to the exemplary embodiment of  FIG. 7 , operating element  8  (not shown for simplicity&#39;s sake) is arranged movably substantially in the vertical direction, the vertical motion direction being indicated with double arrow  46 . Support carriage  41 , with which operating element  8  is associated, is provided for this purpose. Support carriage  41  is arranged movably along a guide  47  provided on microscope stand  2 , guide  47  comprising a crossed-roller guide that is indicated schematically by way of individually depicted balls. In the event support carriage  41  shown in  FIG. 7  is not immobilized on microscope stand  2 , a downward motion of support carriage  41  is prevented by spring  42  arranged on microscope stand  2 . Shaft  26  mounted on support carriage  41  can project laterally out of microscope stand  2  through longitudinal opening  51  indicated with dashed lines.  
         [0048]     In the second exemplary embodiment, opening  15  provided in microscope stand  2  is embodied as a curved elongated hole  13  or as a circle segment, the circle-segment shape being adapted to the distance between pivot axis  21  of focusing device  20  and rotation axis  27  or shaft  26  of operating element  8 . The circle-segment-shaped opening  15  of  FIG. 8  corresponds to curved elongated hole  13  shown in  FIGS. 2 and 3 . The pivoting motion of focus device  20  is indicated here by curved double arrows  55 .  
         [0049]      FIG. 9  is a sectioned view of a further embodiment of the invention in which an electronic coding of the rotary motion of operating elements  8   a  and  8   b  of microscope  1  is performed. Operating elements  8  provided on microscope stand  2  encompass a coarse drive  8   a  and fine drive  8   b . Coarse drive  8   a  of operating element  8  is operable by the operator via rotary knobs  35 . Rotary knobs  35  of coarse drive  8   a  are nonrotatably connected to first shaft  26 , so that a rotation of a rotary knob  35  directly effects rotation of shaft  26 . In the exemplary embodiment described here, shaft  26  is connected to a coding disk  60 . Upon rotation of shaft  26  with operating elements  8 , coding disk  60  is thus also rotated, and the rotation of the coding disk is detected with a sensor element  61  and converted into corresponding electrical signals that are used to activate a motor  62 . Motor  62  serves to move microscope stage  3  in the direction of optical axis  5 , thereby resulting in focusing of specimen  7  present on microscope stage  3 . A displacement of operating elements  8  in terms of their position on microscope stand  2  is accomplished in accordance with the exemplary embodiments described in  FIG. 7  and  FIG. 8 .