Abstract:
A comparison optical system ( 1 ) having an illumination system for specimens is disclosed, the comparison optical system ( 1 ) being equipped with several macroscopes ( 2   a   , 2   b ). The macroscopes ( 2   a   , 2   b ) are connected to one another via a bridge ( 3 ). Each macroscope ( 2   a   , 2   b ) is connected to an attachment device ( 25   a   , 25   b ) for the illumination system. The attachment device ( 25   a   , 25   b ) is constructed from several movable arms ( 30, 32, 35 ) and an adjustable holder ( 37 ) for a light source.

Description:
RELATED APPLICATIONS  
         [0001]    This application claims priority of the European patent application 02 102 520.0 which is incorporated by reference herein.  
         FIELD OF THE INVENTION  
         [0002]    The invention concerns a comparison macroscope having an illumination system for specimens. The invention concerns, in particular, a comparison optical system having an illumination system for specimens, the comparison optical system being equipped with several macroscopes that are connected to one another via a bridge and thereby coupled mechanically and optically to one another.  
         BACKGROUND OF THE INVENTION  
         [0003]    German Patent DE 30 06 379 discloses a defect inspection system for comparative inspection of a standard specimen and a test item. The test item and the standard specimen are on a common support, and both the standard specimen and the test item are imaged via optical means and combined so that a comparison is possible. A transmitted-light illumination system is provided for illumination of the sample.  
           [0004]    U.S. Pat. No. 4,403,839 describes a comparison optical device that is embodied for simultaneous observation of two specimens. A bridge encompasses the optical means for combining the beam paths that are generated by the microscope or macroscope. Illuminating light is introduced into the system by means of the photo tube. The document does not mention how the individual specimens must be arranged on one or more stages.  
           [0005]    These macroscopes described above are used in corresponding systems, which are embodied as comparison macroscopes, for performing forensic comparative examinations. In a very well-known embodiment, two individual macroscopes, connected to one another by a bridge, are used. The bridge contains an apparatus for combining the two individual images generated by the individual macroscopes. Through a common tube arranged on the bridge, the operator of the comparison macroscope can view in superimposed fashion the images of specimens arranged on two different stages. Respective blocking of portions of the two samples corresponding to one another yields a composite image which makes possible a direct comparison, for example, of one sample half to the other sample half.  
           [0006]    In forensic investigations, crime-solving often requires that an image of a first sample be compared to the image of a second sample in order to obtain more detailed information about the circumstances of a crime.  
           [0007]    The specimens compared to one another are, for example, the impressions produced on cartridge cases by the firing pin of a weapon, in order to determine whether the same firearm was used in two or more crimes.  
           [0008]    A further known application of optical comparison investigations consists in checking the authenticity of documents, especially banknotes, in order to determine whether they are counterfeit.  
           [0009]    Lastly, crime-solving often requires comparing, for example, clothing fibers found at the crime scene to fibers of known articles of clothing, in order to obtain information about how a perpetrator was dressed at the time of a crime.  
         SUMMARY OF THE INVENTION  
         [0010]    It is the object of the invention to create a comparison optical system which allows a user to establish reproducible conditions. The object of the invention is, in particular, to achieve reproducible illumination conditions for a specimen.  
           [0011]    This object is achieved by way of a comparative optical system comprising:  
           [0012]    two macroscopes,  
           [0013]    a bridge which couples the macroscopes mechanically and optically to one another,  
           [0014]    an XYZ stage associated to each macroscope for placing a sample thereon,  
           [0015]    an illumination system for specimens placed on the XYZ stage, and  
           [0016]    an attachment device for the illumination system is connected to each macroscope, wherein each attachment device has several movable arms and an adjustable holder for a light source.  
           [0017]    The invention has the advantage that the user of the comparison optical system can reproducibly examine specimens that were already examined some time ago. The comparison optical system comprises several macroscopes that are connected to one another via a bridge. The macroscopes are thereby mechanically and optically coupled to one another. Each macroscope is connected to an attachment device for an illumination system, the attachment device comprising several movable arms and an adjustable holder for a light source. Each macroscope is equipped with a rotatable ring to which a first arm is attached. The rotatable ring is equipped with a scale and can be immobilized using a locking screw. Provided at the end of the first arm opposite the rotatable ring is a first clamping apparatus on which a second arm, equipped with a scale, is guided. Provided on the second arm, opposite the first clamping apparatus, is a second clamping apparatus in which the second arm and a third arm are guidable perpendicular to one another, and that a holder for an illumination system is mounted opposite the second clamping apparatus. It is particularly advantageous if the illumination system or light source is embodied as a light guide. The light exit surface of the light guide is clamped in the holder, and directed onto the particular specimens to be examined.  
           [0018]    Further advantageous embodiments of the invention are evident from the dependent claims.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    The subject matter of the invention is depicted schematically in the drawings and will be described below with reference to the Figures, in which:  
         [0020]    [0020]FIG. 1 is a perspective view of an embodiment of a comparison macroscope having a device for attaching an illumination system for a specimen;  
         [0021]    [0021]FIG. 2 is a perspective detail view of the device for attaching an illumination system, and of the installation of the device on the macroscope;  
         [0022]    [0022]FIG. 3 is a detail view of an adjustable attachment apparatus having a holder for a light source; and  
         [0023]    [0023]FIG. 4 is a detail view of the attachment device of FIG. 3 along line A-A. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]    [0024]FIG. 1 shows a comparison optical system  1 . In this embodiment, comparison optical system  1  comprises a first and a second macroscope  2   a  and  2   b  that are configured as image-acquiring optical subsystems. First and second macroscope  2   a  and  2   b  are mechanically and optically connected to one another via a bridge  3 . Bridge  3  possesses a viewing port  4  for a user, and a tube  5  having a connection  6  for a camera (not depicted). Viewing port  4  for the user can be configured pivotably in order to maintain an ergonomic working position for the user. Tube  5  can additionally possess a further connection  7  with which, for example, a second camera (not depicted) can be attached. A first XYZ stage  8   a  is associated with first macroscope  2   a . A second XYZ stage  8   b  is associated with second macroscope  2   b . A specimen to be compared  9   a  and  9   b  is placed respectively on first and on second XYZ stage  8   a  and  8   b . In comparison macroscopy, both bullets and tools are assessed as specimens, and the traces left thereby are optically compared to one another and evaluated. This is done, in most cases, by splitting the image in the middle so that specimen  9   a  positioned on first XYZ stage  8   a  is visible in the left half, and the specimen  9   b  positioned on second XYZ stage  8   b  is visible in the right half.  
         [0025]    Bridge  3 , together with first and second XYZ stage  8   a  and  8   b , is mounted on a column  10  via a dovetail guide  11 . By way of dovetail guide  11 , bridge  3  attaches. Column  10  is displaceable in the Z direction, or vertically, relative to the surface of XYZ stages  8   a  and  8   b . The movement of bridge  3  allows coarse focusing of the specimens, present on the two stages  8   a  and  8   b , whose structures are to be compared. Column  10  itself is joined to a base  12  which is substantially wider than column  10  in order to achieve sufficient stability and steadiness for comparison optical system  1 . Arranged between the first and on the second XYZ stage  8   a  and  8   b  is a control and adjustment apparatus  14  with which various functions of comparison optical system  1  can be adjusted or modified. Control and adjustment apparatus  14  possesses several actuation elements with which various functions of comparison optical system  1  can be actuated. It is self-evident that control and adjustment apparatus  14  depicted in FIG. 1 can be variously embodied.  
         [0026]    The two XYZ stages  8   a  and  8   b  are displaceable in the X direction, Y direction, and Z direction by way of several motors  16 . A first and a second remote control device  18   a  and  18   b  can moreover also be associated with comparison optical system  1 . In this embodiment, the first and a second remote control device  18   a  and  18   b  are each connected to comparison optical system  1  via a cable  19 . It is self-evident that the connection can assume any technical configuration, for example radio, infrared, etc. Comparison optical system  1  can additionally have associated with it a PC  20  that, via an RS232 cable or USB cable  21 , supplies control signals to comparison optical system  1  and receives image data or settings data from comparison optical system  1 . The image data are displayed to the user on a monitor  22  that is connected to PC  20 . The current settings data of comparison optical system  1  can also be displayed to the user on monitor  22 . Each macroscope  2   a  and  2   b  is moreover connected to an attachment device  25   a  and  25   b  for specimen illumination (see FIG. 3).  
         [0027]    [0027]FIG. 2 is a perspective detail view of attachment device  25   b  that is associated with second macroscope  2   b . Attachment device  25   b  serves to hold an illumination system for the respective specimen  9   a  or  9   b  present on XYZ stage  8   a  or  8   b . Elements that correspond to the elements of FIG. 1 are labeled with the same reference characters. Attachment device  25   b  is attached to macroscope  2   b  on a rotatable ring  26   b  that is equipped with a scale  27 . Rotatable ring  26   a  or  26   b  is rotatable about an axis  23 . Attachment device  25   b  encompasses a first arm  30  that is bolted onto rotatable ring  26   b . Associated with scale  27  is a read-off mark  28  that is used to read off the scale on rotatable ring  26   a ,  26   b . Rotatable ring  26   a ,  26   b  can be immobilized by means of a locking screw  29 . Provided on an end of first arm  30  located opposite rotatable ring  26   a ,  26   b  is a first clamping apparatus  31  in which a second arm  32 , also equipped with a scale  33 , is guided. Provided on second arm  32  opposite first clamping apparatus  31  is a second clamping apparatus  34  in which second arm  32  and a third arm  35  are guidable perpendicular to one another. Third arm  35  is also equipped with a scale  36 . A holder  37 , which has a scale  38  on the periphery, is mounted on third arm  35  opposite second clamping apparatus  34 . Holder  37  is rotatable about an axis  24 . Holder  37  moreover possesses an opening  39  in which the illumination system for the specimen can be attached. Additionally mounted on macroscope  2   b  is a nosepiece  17  with which various objectives (not depicted) can be brought into the beam path of macroscope  2   b.    
         [0028]    [0028]FIG. 3 is a detail view of attachment device  25   b . First arm  30  carries first clamping apparatus  31 ; and on first arm  30  opposite first clamping apparatus  31 , a shoe  40  is connected to first arm  30 . With shoe  40 , first arm  30  can be attached to rotatable ring  26   b  of second macroscope  2   b . On first macroscope  2   a , an attachment device  25   a  is of course attached to rotatable ring  26   a . Attachment of shoe  40  to rotatable ring  26   b  is accomplished via at least one screw  41 . First clamping apparatus  31  possesses a thumbscrew  42  which clamps second arm  32  that is guided in first clamping apparatus  31 . Second clamping apparatus  34 , in which second arm  32  is also guided, is provided opposite first clamping apparatus  31 . The ends of second arm  32  are each equipped with a screw  43  whose head has a greater diameter than second arm  32 , in order thereby to prevent second arm  32  from sliding out of first clamping apparatus  31  and second clamping apparatus  34 . Third arm  35 , which carries holder  37  opposite second clamping apparatus  34 , is guided in second clamping apparatus  34  perpendicular to second arm  32 . A light guide  44 , which transports illuminating light from a light source  52  to the specimen, is secured in holder  37 . Light exit end  45  of light guide  44  is secured in the holder. Holder  37  is rotatable so that illuminating light can be optimally directed onto the specimen. Light source  52  is also connected to PC  20 , and receives therefrom corresponding control signals for adjusting the intensity.  
         [0029]    [0029]FIG. 4 is a sectioned depiction of attachment device  25   a  or  25   b  along the section line depicted in FIG. 3 and labeled A-A. First clamping apparatus  31  is attached to first arm  30  with a screw  50 . Shoe  40  is permanently attached to first arm  30  opposite first clamping apparatus  31 . Shoe  40  possesses the curvature of rotatable ring  26   a , and is attached thereon using two screws  41 . Second arm  32  is guided in first clamping apparatus  31  and can be clamped with thumbscrew  42 .  
         [0030]    Rotatable ring  26   a  and  26   b  possesses a scale  27 , second arm  32  possesses a scale  33 , third arm  35  possesses a scale  36 , and holder  37  also possesses a scale  38 . When specimens are examined, the illumination is adjusted, using attachment device  25   a  and  25   b , in such a way that the illumination conditions which are established ensure optimum detection of the features to be examined. A read-off mark (not depicted) can likewise be provided respectively on clamping apparatus  31 , clamping apparatus  34 , and holder  37  in order to inform the user as to the read-off point for the respective scales. The values for optimum illumination situations can be read off from the various scales  27 ,  33 ,  36 ,  38 . The values are recorded, for example in order to obtain the same illumination conditions for later examinations. These values can be recorded and stored in a table in PC  20 , for example together with the image file and the electrically detectable macroscope settings, e.g. position of the semi-apertures, objective magnification, lamp intensity, etc.,. When specimens  9   a  and  9   b  are once again comparatively examined, the file in PC  20  pertaining to the specimens can be retrieved. The values are set on attachment device  25   a  and  25   b  so that the same illumination conditions can be reproduced. By analogy with the values that are read off from scales  27 ,  33 ,  36 ,  38  and stored in the file in PC  20 , further settings data, for example the position of XYZ stages  8   a ,  8   b , the objective used, illumination intensity, etc. can automatically be saved in the file when the image is acquired. When another examination is made, these values can then be automatically traveled to or set. A prerequisite for this is appropriate motorization of macroscopes  2   a ,  2   b.