Abstract:
A microscope is disclosed for observing a magnified area. Fade-in means arranged in the path of the rays of the microscope reflect a thin focused beam of light into the path of the rays. The beam of light is deflected or modulated by deflecting means to supply an image that can be recognized by an observer. The image may be projected onto the object either directly or indirectly, for example through a diffusing screen.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a microscope having at least one beam path and an optical system along an optical axis, and having a fade-in element for reflecting in image information for an observer&#39;s eye. Microscopes in the sense of the invention are to be understood principally, but not exclusively, as devices which have a main objective, a tube and an eyepiece for looking into. In the widest understanding of the invention, therefore, all other optically magnifying devices are to be understood which are directed onto an object to be magnified and make visible to the observer&#39;s eye a magnified image of the object observed. Microscopes, in particular stereomicroscopes, for example surgical microscopes, in particular also video (stereo)microscopes which are connected to an electronic data processing unit and/or a display are comfortable for a user when the latter is not exclusively dependent on the image currently seen through the main objective of the microscope, but also obtains when looking into the tube of the microscope additional information which is generally superimposed on the currently seen image. This can be graphic characters, symbolic representations, marks, but also superimposed images of the same object which are obtained, for example, with the aid of image processing software from the currently seen object or by means of other visualizing measures (for example X-ray pictures, CT etc.) from the same object. Microscopes with fade-in possibilities or image superimposition possibilities are also used, inter alia, in technology, for example materials engineering, material analysis, silicon technology criminology, etc., but also, in particular, in medicine for diagnosis, serological examinations, during operations etc. 
     Chiefly in the case of surgical microscopes and, in particular, during an operation, a quantity of information arises which can be of great importance to the surgeon. This is, for example, information on the patient or his state of health or patient parameters such as pulse, blood, pressure, oxygen content of the blood etc. These are in addition to the currently observed superimposing images, for example, information on specific parameters of the microscope, information on the position of the observed operation zone, as well as control data which, for example, the surgeon delivers at will via control elements such as computer mouse or foot switch to the data processing device or to control elements for the microscope, in order to control the latter as required, for example to focus it, etc. 
     The use of the invention in the field of surgical microscopy will be taken up below by way of example. The invention is also applicable in other fields. 
     Surgical microscopes are used by the operating surgeon for optical magnification of the operation zone. Operation technology is so far advanced in this connection that magnifications in the region of 50 fold and above are no rarity. It is important during an operation that the all important information is transmitted to the operating surgeon as quickly and unambiguously as possible, in order for him to be able to conclude the operation in as short a time as possible. Since the operating surgeon preferably removes his eyes as little as possible from the eyepiece of the surgical microscope, and, conversely, difficulties of comprehension can be expected with the spoken word, it is obvious for important information such as, for example, patient data, micoscope control data or positional data to be rendered visible in the tube. 
     This is achieved according to known techniques by representing the relevant information on a display and reflecting the image of this display into the tube via a beam splitter. Because the user always wants a good light yield for the object observed, which can frequently be ensured by high illumination densities at the object, the problem of adequate optical density of the image reflected in or superimposed often arises in the case of reflecting in. In this case, tube displays (CRT) frequently provide no way out. The use of LCDs with strong background illuminations is; attended by disadvantages in the field of resolution and also in attempting to reproduce thin lines, also since the pixel width of the LCDs is relatively large, and therefore relatively wide minimum line thicknesses are prescribed. Moreover, LCD pixels form rasters which can produce problems with edge definition and resolution. 
     If it is now desired, for example, to have edge improvements, image colorings, contrast improvements or other marks which are as thin as possible, and which have been prepared, for example, after prior recording by means of video technology and by means of electronic image processing, it can happen disadvantageously that the known possibilities produce unsatisfactory performance with regard to brightness and/or line thickness. Contouring would be desirable, but not: achievable optimally using the means of the prior art. 
     A special field for the superimposition of images rises, for example, in the application of computer tomography (CT) or magnetic resonance imaging (MRI) in conjunction with stereomicroscopy. Data are obtained from CT and MRI in order to obtain a sectional image of the zone of interest from the patient which, in the final analysis after EDP, permits the representation on a computer monitor (stereo display screen) of a three-dimensional model which is faithful to reality. By using such three-dimensional images, the attending doctors are better able to localize the type and spread of the diseased area. However, it is frequently the case that both the image currently seen and the available three-dimensional representation of X-ray or CT image data are not clear enough for the relevant area to be identified during operation in a marked-off fashion with sufficient clarity from the remaining region. 
     As already mentioned, contour reworking or contour representation suffice for this identification to be performed optimally, but these are to be as bright and thin as possible in order not to cover other details. 
     Accomplishing this is one of the main objects on which the invention is based. 
     SUMMARY OF THE INVENTION 
     This object is achieved, for example, by utilizing the method and device describe herein. 
     The problems described are eliminated by superimposing onto a first image, seen through the main objective ( 8 ) of a microscope, such as shown in FIG. 1 at least one second image from a thin, focused light beam, in particular a laser beam which is deflected and/or modulated in a deflecting device and reflected into the beam path of the microscope via a fade-in element in such a way that it visibly represents the second image for an observer&#39;s eye. A thin light beam, in particular a laser beam, can be generated in a virtually arbitrarily thin and bright fashion. 
     It is relatively easy for the components newly required for this in accordance with the invention to be integrated into a microscope. Fade-in elements, suitable light sources, in particular lasers, are known per se to the person skilled in the art. However, despite their favorable properties, they have evidently not been used so far for the effects being sought in the field of microscopy. 
     It is not important here for the purpose of the invention whether the thin light beam or laser beam is projected by the optical system directly onto the retina or onto an interposed diffusing screen, or else directly in the other direction onto the object itself, in order to represent the corresponding marking there on the object surface. 
     Within the scope of the invention, there are both variants in which, in the operating state, the light beam extends in the region of an intermediate image plane of the optical system in a fashion approximately parallel to the optical axis in the direction of the eyepiece, and variants in which a diffusing screen on which the light beam can be scattered is arranged in the intermediate image plane. 
     For the purpose of the invention, a diffusing screen is in this case any optical element on which a thin light beam is scattered upon impingement in such a way that its point of contact can be seen from different points of view. Thus, this could also be an uncoated glass plate. However, it can also be, for example, a beam splitter to which a scattering coating is applied to a surface inside the optical system, or one surface of which is roughened. 
     According to the invention, any desired pictorial information can be fed to the observer by means of a light beam and deflecting device. In accordance with a specific embodiment of the invention, the deflecting device and/or the light source is controlled by an image processing device for contour representation, which is coupled to an image recording device which is coupled to the optical system via a further fade-in element. This permits direct feedback between the image of the object which is seen and the image represented by means of the beam. This variant is advantageous by virtue of the brightness of a focused light beam. Despite a bright operating field of view, the area to be emphasized is seen by the operating surgeon in a clearly highlighted fashion. This is so, of course, even in the case of variants in which not only the image seen optically is the basis for the image representation of the beam, but also the diagnostic data, acting as though at the same object position, from a diagnostic data device (for example a CT, MRI, PE device or the like). 
     In the latter variants, it is preferred to provide in each case at least one beam path per observer&#39;s eye (stereomicroscope), it being the case that in each beam path in each case one left-hand and right-hand item of partial image information, which are offset in terms of perspective in relation to the respective other one can be reflected in from one, or in each case one deflecting device via a fade-in element in each case, the deflecting device(s) being controlled by an image recognition and/or image processing device. An image recognition device is to be understood as a system which is able to recognize the identity of the objects observed through different observation units, and in this way enables image data to be superimposed in the correct position. 
     The preferred method is yielded in this connection when the deflecting device is controlled by image information obtained from the object observed through the microscope, so that, for example, contours of object details are retraced, or object details are represented by means of grid lines or the like at the actual site of the object detail in the visual field area, of course, such grid lines have the ideal effect principally in the case of stereomicroscopes when they are used to retrace a specific object detail (for example a tumor) in three dimens ions or in plastic terms. 
     In accordance with a development of the invention, a continuously controllable light valve is placed in front of the light source, so that a user can regulate the brightness of the image faded in by means of the beam. When conventional lamps are used, it is also possible, of course, for their brightness to be regulated via the power supply. In the case of lasers, in particular, however, the abovementioned variant is to be recommended. Operating convenience is enhanced if the light color of the light source or of the laser can also be adjusted, something which is possible by measures known to experts in light sources or lasers. 
     Further advantages follow in accordance with further special embodiments of the invention in which the image observed (background image) exerts a reaction on the superimposed image. According to the invention, the procedure here is based on two points of view: relative brightness of individual pixels with respect to one another, and total brightness of the image, limited by possible adaptation behavior. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further details and embodiments of the invention as well as variants thereof follow from the drawing. Of the figures represented there, by way of example: 
     FIG. 1 shows a design principle of a microscope according to the invention, without diffusing screen; 
     FIG. 2 shows a variant of FIG. 1 with diffusing screen and a system for reflecting in patient data; 
     FIG. 3 shows a variant with a system for reflecting in and out additional image data and feedback therebetween; 
     FIG. 4 shows a stereomicroscope with 3-D image super-imposition, and 
     FIG. 5 shows a design with a small movable mirror in the beam path. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The figures are described together and inclusively. The same reference symbols denote identical components. The same reference symbols with different indices denote similar or functionally similar components. The invention is not restricted to the exemplary embodiments represented. Further arbitrary variants can be represented in combination. 
     One the principles of the invention is illustrated in FIG.  1 : 
     A beam path  1  having a magnifying optical system  33 , of which only two lenses, specifically a main objective  8  and an eyepiece  18 , are represented symbolically, has an obliquely positioned beam splitter  32   a  by means of which both the image information is directed to the eyepiece  18  through the main objective  8 , and image information reflected in from the side is directed to the eyepiece  18 . The beam splitter can be a semireflecting mirror or the like. It can also possibly be constructed in a miniaturized fashion as a small mirror which is bonded on a glass plate perpendicular to the optical axis  7 , such a latter design always functioning with divergence of the beams  101 , which, if appropriate, requires additional computational outlay for the beam deflection. According to the invention, the image information reflected in from the side comprises an image of a thin, focused light beam  101 , in particular a laser beam, which follows the lines to be represented pictorially in a repeated fashion at the required speed, thus rendering a coherent image, for example lines, numbers, letters, symbols, areas etc., visible to an observer. These are scattered on diffusing screen  108   a  and are distinguished there by a good brightness (virtually unlimited, depending on the laser power) and thus by a distinct contrast with respect to the image seen through the main objective  8 . The image of the scattered laser beam is projected onto an intermediate image plane  103  of the tube by means of a lens  31  via the beam-splitting mirror  32   a.  The beam is deflected or moved by a deflecting device  102 , known per se which has mirrors or the like which can move under control, and in this way can deflect a beam  101  irradiated into it. It goes without saying that a plurality of beams with, if appropriate, a plurality of deflecting devices as well, could also be provided simultaneously. It is also conceivable, if required, for a plurality of laser beams to be run together on the diffusing surface, in order to increase the energy density and thus the brightness. The movement of the beam  101  is represented symbolically by a dashed arrow of rotation. The beam  101  is obtained from a light source  64 , in particular from a laser, which could, of course, also be integrated into the deflecting device. 
     Also represented in the exemplary embodiment shown is a light valve  107  which makes the brightness of the beam  101  controllable. The deflecting device  102 , light valve  107  and light source  64  can preferably be controlled arbitrarily from outside, in order for the image to be represented by the beam  101  to be configured optimally in terms of beam quality for the observer, whose eye  100  is represented. 
     In the exemplary embodiments in accordance with FIG.  1  and FIG. 3, the beam  101  is deflected in such a way that, via the eyepiece  18 , it projects the image it produces directly into the observer&#39;s eye  100  or onto the retina thereof. The light source  64  used can thus be relatively weak optically. In the region of an intermediate image plane  103  of the optical system  33 , the beams  101  are thus preferably parallel to the optical axis  7  of the optical system  33 . However, it is not essential for the beam  101  to be faded in at the point shown. A variant is also conceivable in which the beam is directed into the observer&#39;s eye  100  only after the eyepiece  18 . This variant is expedient particularly since it does not unnecessarily increase the required distance of the eye from the eyepiece. 
     The object observed is represented symbolically with  22 , the purpose of this design being, for example, to draw a high-contrast, bright line around an object detail  22   a.  The scope of the invention therefore also covers that variant in which the beam  101  is projected not directly into the observer&#39;s eye  100 , but directly onto the object  22 , the beam splitter  32   a  then having, of course, to act inversely. 
     The beam can be used to represent, for example, patient information data such as blood pressure, heart rate etc. in graphic form, as indicated in FIG.  2 . 
     By contrast with the first variant, a laser beam  101  is directed there straight into the eye, as indicated symbolically. The optician knows the measures required to project the beam  101  correctly straight onto the retina. A diffusing screen can thereby be eliminated, and the beam can apply a high brightness and level of contrast with the correspondingly lower amount of energy. The image prescribed by the deflecting device  102   a  is thus produced directly on the retina and is superimposed precisely there on the image seen through the main objective  8 . In this design, it is immaterial which angle the beams make with the optical axis  7 , to the extent that they impinge only at the desired site on the retina. As an alternative to this design, it would be possible to use in the intermediate image plane  103  a diffusing grating at which only the wavelength region of the laser light is scattered, while the other light wavelength regions pass unimpeded, with the result that despite the diffusing screen there is no appreciable darkening of the image seen below the main objective  8 . 
     In the example represented, blood pressure and heart rate are represented in the area of the object detail  22   a  which is seen. This patient information is obtained by known measuring instruments and, if appropriate, conditioned via a data conditioning unit  89  in such a way that suitable control data can be fed to the deflecting device  102   a  in order to permit quick real-time operation. 
     The example represented in FIG. 3 concerns an image-processing (video) evaluation of an image seen through the main objective, for example object detail  22   a  through an image processing device  104   a  which is coupled to an image recording device  9   a  (for example CCD). The image recording device  9   a  is coupled to the beam path  1  via an imaging optical system and via a beam splitter  32   b,  with the result that the image processing device  104   a  recognizes the object detail  22   a  being observed. Represented by dashes are the image recording device  9   b  and image processing device  104   b,  which can be provided in addition to or as an alternative to  9   a  and  104   a . In the variant drawn with full lines ( 9   a ,  104   a ), in addition to the image of the object detail  22   a , the image processing device  104   a  also has available the image from the deflecting device  102   b  which is projected inversely by the device  104   a . Subsequent correction is therefore easily possible. The present example is concerned with detecting contours on the object detail  22   a  and enhancing them by means of beam superimposition ( 101 ). This makes it easier for an operating surgeon, for example, to make out the areas involved more quickly and more clearly. 
     The beam splitter  32   a  is arranged in this example approximately centrally about an intermediate image plane  103 , and is itself provided with a surface  108   b  which scatters to a slight extent, with the result that an additional diffusing screen is eliminated. 
     In the exemplary stereomicroscope in accordance with FIG. 4, diffusing screens  108   a  are again provided, on which partial images offset by the parallax are represented per beam path  1   a,    1   b  relative to the respective optical axis  7   a, b;  said partial images are combined in the observer&#39;s brain to form a 3-D image. The deflecting devices  102   c, d  are driven for this purpose by an image recognition device  105 , possibly with an image processing device  104 , which receives its image information—possibly via a data conditioning unit ( 89 ) (not represented) and/or via an image memory—from a 3-D image data recording unit or diagnostic data device  106 . The latter preferably operate not in the visible wavelength region as do the microscope beam paths, but by means of X-rays, alternating magnetic fields, positron beams, ultrasound or the like. 
     Thus, for example, it is possible using this design to superimpose three-dimensional grid lines calculated from the abovementioned patient data on an object detail  22   a  which is seen three-dimensionally or is to be seen theoretically, with the result that an operating surgeon again obtains an area of interest to him in a clear and bright fashion and highlighted with thin lines. 
     Of course, arbitrary combinations of superimposed images are also contained within the scope of the invention, such as alphanumeric data, contour enhancement and encirclements of areas. 
     The variant in accordance with FIG. 5 operates with a micromirror deflecting unit having a drive in the tube  33 , which directs a laser beam  101  in the correct position against the observer&#39;s eye  100 . 
     Not shown in more detail, but familiar to the person skilled in the art as being within the scope of the invention are variants with colored lasers or with electron beams which cause suitable fluorescent screens or the like to light up with patterns. Such designs also comprise, if appropriate, vector display screens, where lines are frequently retraced in each case by the beam. The invention also covers variants in which instead of being fed directly to the eye the light beams are firstly led to the object being observed and scattered thereon. 
     List of Reference Symbols 
     This list of reference symbols also contains reference symbols of Figures which are contained in the above- mentioned applications since, as mentioned, these count as also having been disclosed for combination purposes within the framework of this invention. This applies, in particular, to the microscopes with special beam paths and beam splitters, and to the devices for measuring the magnification and the distance from the microscope to the object as well as to microscopes for stereotactic operations etc. 
       1  a, b First beam path 
       2  a, b Second beam path (first beam paths laid geometrically one above another) 
       3  Mechano-optical switching element 
       3   a,    3   b,    3   c  Opaque and preferably silvered stop 
       3   d  LCD shutter element 
       3   e  Micromechanical leaf mirror design 
       3   f  LCD exchangeable shutter element 
       4  Beam splitters 
       4   a ,  4   b  Beam splitters 
       4   c  Beam splitter for cutting out the measuring beam 
       5  Screen 
       5   a  Semicircular surface 
       5   b  Residual surface of the screen  5   
       5   c  Circular segment surfaces 
     
       5 
       d  
     
       6  Spindle for screen 
       7  Central axis 
       7   a,    7   b  Central axis 
       8  Main objective 
       9   a  Electronic image recording device 
       10  Display 
       10   a  Display 
       11  a, b Mirror 
       12  a, b, c Adjusting device 
       13  Zoom 
       14  a,b Motor 
       15  Reciprocal drive 
       16  Supply lead 
       17  Light source 
       18  Eyepiece 
       19  Deflecting mirror 
       20  Push rod 
       21  Rigid mirror 
       22  Object 
       22   a  Object detail 
       23  a, b, a′, b′, c, d Plane plate 
       24  Rotary actuator 
       25  Linkage 
     
       26 
     
     
       27 
     
     
       28 
     
     
       29 
     
       30  Leaf mirror of  3   e    
       31  Tube lens 
       32  Fade-in element 
       32   a  Beam splitter 
       32   b  Mirror 
       32   c  Second fade-in element 
       33  Magnifying optics 
       34  Arrows 
       35  Further mirror 
       36  Actuator 
       37  Bar 
       38  a, b Deflecting mirrors 
       39  Retroprism 
       40  Balance weight 
       41  Backing plate a, b, c: prismatic with integrated mirror 
       42  Color filter 
       43  Interval switch 
       44  Microprocessor 
       45  Measuring array a 
       46  Reference array a 
       47  Module for image data transmission 
       48  Extraneous image data input 
       49  Positioning motor for zoom  13 : a, b 
       50  Connecting lines a-g 
       51  Magnification display a, b, c 
       42  Cam disk 
       53  Coupling 
       53   a  Between positioning motor  49  and zoom  13   
       53   b  Between cam disk  52  and magnification-d [sic] display  51   b    
       54  Mechanical tap 
       55  a, b Pointers 
       56  Laser 
       57  Measuring beam a, b, c, c 1   
       58  Reference beam 
       59  Arrows for displaceability of the fade-in element  32   
       60  Microscope beam path a-e 
       61  First deflecting element a 
       62  Focusing element a, b 
       63  Optical conductor end piece a, b 
       64  Light source a 
       65  Second deflecting element 
       66  Sensor 
       67  Distance range a 
       68  Connecting line 
       69  Distance measuring system 
       70  Connection 
       71  Magnification measuring unit 
       72  Position determining system a, b 
       73  Interferometer 
       74  Semireflecting mirror 
       75  Reflector 
       76  Detector 
       77  Electromechanical adjusting element 
       78  Interferometer control 
       79  Grating 
       80  Detector CCD 
       81  Stages 
       82  Microscope 
       83  Arrangement for measuring the magnification of the microscope 
       84  Arrangement for measuring the object/microscope distance 
       85  Position-measuring system for determining the absolute position of the microscope in space, and also for the purpose of being able to reach a conclusion upon the position of the visual field at the object from knowledge of the object/microscope distance 
       86  Toolbox for different user programs 
       87  Command control element (computer mouse) 
       88  Command control element for controlling the movement of the microscope (for example foot switch) 
       89  Data conditioning unit 
       90  Computer (workstation), 
       91  Control switch for microscope 
       92  Electromechanical control unit for microscope (zoom, focus, etc.) 
       93  Object 
       94  Second device (for example MRI unit or CT unit) 
       95  Superimposing device 
       96  Joint on the stand 
       97  Adaptive control device 
       98  a, b Detection system 
       99  Memory 
       100  a, b Observer&#39;s eye 
       101  a, b, c Beams 
       102  a, b, c, d Deflecting device 
       103  a, b Intermediate image plane 
       104  Image processing device 
       105  Image recognition device 
       105  Diagnostic device 
       107  Light valve 
       108  a, b Diffusing screen 
       109  Test object 
       111  Coordinate system 
       112  Enhanced contour line 
       113  Micromirror deflecting unit 
     b Spacing of the measuring beams  57   a  and  57   b    
     b ′ Spacing of the measuring beams  57   a  and  57   b  at the measuring array 
     d  1 ,  2  Stereobasis