Abstract:
An optical module for increasing magnification of a microscope includes an objective and an eyepiece between which is an optical path for light to travel. The optical includes light diverging elements for dividing the optical path into two parallel light paths after leaving the objective; and several orthonormally-arranged reflective elements including at least a first and a last reflective element, each reflective element having a reflective surface diagonal relative to the orthonormal arrangement of the elements, and also arranged to successively reflect the parallel light paths, from element to element, from the objective when the module is inserted in the optical microscope, beneath the eyepiece. Also included are light converging elements for converging the parallel paths into a single path before producing an image at the eyepiece.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to the field of optical microscopy, and more specifically to an apparatus for enhancing magnification. 
         [0003]    2. Prior Art 
         [0004]    The prior art in the area of optical microscopes that entails the use of prisms as reflectors to achieve an enhanced capability are, on the one hand, limited to systems seeking to create a dual objective as, for example, to view a specimen at either two different magnifications or from two different directions at the same time, and other hand, microscopes seeking to achieve a stereoscopic effect at the eyepiece thereof, that is, a three-dimensional viewing of a specimen. The prior art which reflects one or more of these goals is represented by U.S. Pat. No. 5,146,363 (1992) to Nagano; U.S. Pat. No. 5,701,198 (1997) to Schoppe; U.S. Pat. No. 5,764,408 (1998) to Otaki; and U.S. Pat. No. 6,134,01 (2000) to Zavislan. 
         [0005]    The present invention is also an improvement of the microscope module set forth in my application, now abandoned, of US. 2002/0181094 A1. 
         [0006]    Of the above, only the reference to Otaki exhibits any awareness of the capability of the use of reflecting and deflecting prisms to effect a change of the external size or geometry of the microscope itself. Also, none of these references, or others known to the inventor, suggests the use of selectable combinations and positioning of wedge or triangular prisms to effectively increase the length of the optical path between the eyepiece and the objective to thereby increase the magnification of the optical microscope. Further, Otaki employs a three-dimensional path, which is not employed herewith. 
         [0007]    Other prior art is U.S. Pat. No. 3,645,602 (1972) to Clave. It does not utilize an optical path of orthonormal rows and columns of mirrors or prisms, as taught herein, makes use of a Barlow amplifier, and does not employ a dual beam light path within the magnification module. 
         [0008]    The present invention meets a long felt need in the art for a conventional microscope of enhanced modification but without significant increase in cost, size or complexity. 
       SUMMARY OF THE INVENTION 
       [0009]    An optical module for increasing magnification of a microscope includes an objective and an eyepiece between which is an optical path for light to be magnified to travel. The optical module comprises light diverging means for dividing said optical path into two parallel light paths after leaving the objective; and a plurality of orthonormally-arranged reflective elements including at least a first and a last reflective element, each reflective element having a reflective surface diagonal relative to the orthonormal axes of arrangement of said elements, and also arranged to successively reflect said parallel light paths, from element to element, from said objective, when said module is inserted in said optical microscope beneath said eyepiece. Also included is a light converging means for converging said parallel paths into a single path before producing an image at said eyepiece. 
         [0010]    It is accordingly an object of the invention to provide a module for the enhancement of the magnification of an optical microscope. 
         [0011]    It is another object to provide a system, inclusive of such a module which, by folding of the optical path, increases the effective length thereof and, with it, the magnification of the microscope. 
         [0012]    It is a still further object of the invention to provide a method of increasing magnification of an optical microscope by providing a plurality of orthonormal reflective elements, in the nature of prisms, between the objective and the eyepiece of the microscope, to effectively fold and, thereby, increase the optical path between the objective and the eyepiece of the system. 
         [0013]    The above and yet other objects and advantages of the present invention will become apparent from the hereinafter set forth Brief Description of the Drawings, Detailed Description of the Invention and Claims appended herewith. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a schematic view that shows a magnification module inserted into an optical microscope. 
           [0015]      FIG. 2  is a schematic view of the lensing arrangement and optical path and geometry of the module input. 
           [0016]      FIG. 3  is a schematic view of a first and embodiment of the magnification module, each including a plurality of reflectors; 
           [0017]      FIG. 4  is a schematic view of the optical path and lensing arrangement geometry of the output of the module to the eyepiece. 
           [0018]      FIG. 5  is a schematic view of a second embodiment of the invention. 
           [0019]      FIG. 6  depicts a plurality of magnification modules cascaded together and inserted into the optical microscope. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    As shown in  FIG. 1 , an optical module  10  can be inserted into a microscope  12 , or similar optical magnification system, to enhance its magnification. The microscope  12  shown in  FIG. 1  comprises a standard light microscope having , e.g., between about 1000× and 4000× magnification. As is conventional, said microscope  12  comprises an objective  14 , an eyepiece  16 , and an optical path  18  extending therebetween. This optical path has a standard length of between about 160 to 190 millimeters (mm), conventionally referred to as the tube length. The optical module  10  is inserted between the objective  14  and eyepiece  16 . An X, Y, Z coordinate which is also shown in  FIG. 1 . 
         [0021]    Shown in  FIG. 2  is the optical path  18  from objective  14  and the beam separation or divergence strategy provided to provide input beams  41 A and  41 B to the optical module  10 , below described. More particularly, light from objective  14  is provided along optical path  18  and axis  19  to a plano-concave lens  15  or equivalent diverging or beam splitting optical element. The curvature at the right side of lens  15  diverges the optical path into parts  17 A and  17 B which thereafter enter plano-convex lens  21  which convergently refracts each of the paths  17 A and  17 B by an angulation equal to the divergent refraction of lens  15 , resulting in parallel output beams  41 A and  41 B. 
         [0022]    As may be noted in  FIG. 3 , these optical outputs of lens  21  are directed into module  10  shown in  FIG. 3  which shows one embodiment of said optical module  10  comprising a plurality of reflective elements supported upon a frame  20  for use within an optical magnification system. The frame  20  comprises a front plate  28  and a rear plate (not shown) with the plurality of reflective elements sandwiched therebetween. Said frame  20  and, therefore, the module  10  as well, are rectangular, having four sides, including an oppositely situated eyepiece side  24  and objective side  26 . The module  10  is inserted into the optical microscope  12  such that the side  26  is adjacent the objective  14  and the side  24  is near the eyepiece  16  of the microscope. The module  10  has a length  28  spanning from side  24  to side  26 . This length  28  is small sufficient that the module  10  can fit between the objective  14  and the eyepiece  16  of the microscope  12 . 
         [0023]    To enhance the magnification, said module  10  is inserted into said microscope  12  and aligned such that light from object  14  passes, in two parallel paths, through said lens  15  and  21  to module  10  and eventually to eyepiece  16  following lens  23 . The reflective elements in the module  10  are arranged to direct light through the optical path  18 . See  FIG. 3 . For example, the light from the objective  14  preferably reflects off of a first reflective element  30  mounted on the frame  20  of the module  10 . This first reflective element reflects both beams  41 A and  41 B to a second reflective element  32  which will deflect the beam to a third reflective element  34 , to a fourth element  36 , to a fifth element  38 , until the beam reaches a final reflective element  40  mounted near the upper side  24  of the module  10 . The last reflective element  410  preferably directs the beam to the plano-convex lens of  FIG. 4  which results in convergence of the beams at point  43  from which the resultant image may be viewed at eyepiece  16 . 
         [0024]    Rays of light from an object below the objective  14  will therefore transverse a path  18  (see  FIG. 2 ) between the objective  14  and the eyepiece  16  that is longer than would exist if the optical module  10  were removed. In effect, module  10  increases, by a factor of at least two, the optical path length between the objective  14  and the eyepiece  16  beyond that of a standard tube length. As such, the optical path  18  between the objective  14  and the eyepiece  16  may be said to be folded such that the space separating the objective from the eyepiece can accommodate a longer optical path length or path  18  or optical axis  19 . The longer optical path is thereby folded to fit into the small region between the objective  14  and the eyepiece  16 . 
         [0025]    Various arrangements of the reflective elements can be employed to fold the optical path between the objective  14  and the eyepiece  16 , as is shown in  FIGS. 3 and 5 . For example, in the embodiment depicted in  FIG. 3  above described, six reflective elements, said first element  30 , said second element  32 , said third element  34 , said fourth element  36 , said fifth element  38 , and said element sixth  40 , are positioned on the frame  20  in two columns, each column comprising three reflective elements. These columns define a Y direction, shown in  FIG. 3 . The three elements may be equally spaced in columns along the Y direction  44 , but need not be equidistantly spaced. In addition, each element  30 ,  36 ,  38  in the first column is aligned with a corresponding element  32 ,  34 ,  40  in the second column. The plurality of reflective elements  30 - 40  therefore comprises three rows, each row comprising two optical elements arranged along an X direction  46  which is orthonormal to said Y direction  44 . The optical elements in each row are preferably, but not necessarily, spaced apart by a same distance as that separating adjacent elements in each Y column. 
         [0026]    The first reflective element  30 , mounted on the frame  20  of the module  10 , comprises a cube having a reflective surface  48  therein oriented at about 45° to the X axis and Y axis, such that incident light will be reflected toward the second reflective element  32  in the X direction, which is the same row as the first reflective element  30 . 
         [0027]    The second element  32  comprises a triangular prism having a triangular cross-section and a reflective surface  50  also oriented at about  450  to the X direction  46  and Y direction  44  such that light will be reflected in the Y direction toward the third reflective element  34  which is situated in the next row. 
         [0028]    The third reflective element  34  is similar to the second element  32 , however the reflective surface  52  is oriented to direct light in a negative X direction  47  toward the fourth reflective element  36  which is in the same row as the third optical element  34 . Accordingly, it has a reflective surface  54  at an approximately 45° angle with respect to the X direction and Y direction, but that is orthonormal to the reflective surface  50  in the second reflective element  32 . 
         [0029]    The fourth reflective element  36  is similar to the third element  32 , however the reflective surface  54  is oriented to direct light in the Y direction  44  toward the fifth reflective element  38  which is the next row. Thus, the reflective surface  54  in the fourth reflective element  28  is parallel to the reflective surface  52  in the third reflective element  34 . 
         [0030]    The fifth reflective element  38  is similar to the fourth element  34 , however the reflective surface  56  is perpendicular to that of the fourth element  54  to direct light in the X direction toward the sixth reflective element  40 , which is in that same row as the fifth reflective element  38 . 
         [0031]    The sixth reflective element  40  also comprises a cube having a reflective surface  60  therein oriented at about 45° to the X direction and Y. Light directed from the fifth reflective element  38  will be deflected from the sixth reflective element  40  in the Y direction  44  and will exit the optical module  10  and propagate toward lens  23  converge at point  43  and to produce an image at the eyepiece  16 . (See  FIG. 4 ). As discussed above, the resulting configuration of elements creates a folded optical path wherein and inputs  41 A/ 41 B of light at the first element  30  will traverse a greater distance through each of the six optical elements  30  to  40  than they would otherwise, directly from the objective  14  to the eyepiece  16 , had the optical module  10  not been inserted therein. 
         [0032]    Note also that although six reflective elements  30  to  40  are employed in the embodiment of  FIG. 3 , the design of the optical module  10  is not so limited. Fewer or greater numbers of optical elements may be employed to increase the optical path length. At least part of this system of reflectors, such as for example the combination of elements  32 ,  34 ,  36 , and  38 , may be repeated one or multiple times to generate increasingly long optical path lengths in one apparatus. In other embodiments, the optical path may span several layers of the optical module, for example in the vertical direction, to further increase path length without increasing overall length and width of the module. 
         [0033]    As shown in  FIG. 5 , the first  102  and sixth  104  optical elements are similar in this embodiment. In preferred embodiments of the invention, one or more elements may comprise a prism, having a reflective interface therein. The elements may comprise a transparent media with a reflective surface formed therein; in such cases, the media provides efficient transmission of light with low attenuation, and preferably minimal chromatic aberration. 
         [0034]    The second  106 , third  108 , fourth  114 , and fifth  116  optical elements are all similar as well, each generally comprising a prism having a triangular shape. These elements may be configured such that the dual light paths are incident on a flat surface of the prism, and subsequently propagate through the prism toward another reflective surface that is angled, e.g., at approximately 45° with respect to the direction of propagation, where the beams of light are reflected and propagated through the prism before emission from another surface in direction which are at approximately 90° to the initial direction of the incoming beams. 
         [0035]    In other embodiments, the reflective surfaces of the elements may be coated with a particularly reflective material, such as aluminum to enhance the reflective capabilities of the element. The elements are preferably made from an optically clear material which provides efficient transmission for light and low chromatic aberration. 
         [0036]    In the embodiment of  FIG. 5 , a module  100  comprises six optical elements defining three columns. The first  102  and the sixth  104  elements are positioned in the column oriented in the Y direction. The second  106  and third  108  elements are positioned in a second column  110  parallel to the first column  112  of the module  100  and the fourth  114  and fifth  116  optional elements are positioned in a third column  118  also parallel to the first  112  and second columns  110  The first column  112  is located centrally on the apparatus  10 , flanked by the second column  110  and third column  118  which are parallel to the first column  112 . The first element  102  and sixth optical element  104  are of the quartz prism type described above, but may be or another preferable reflective type; such as a mirror. The second  106 , third  108 , fourth  114 , and fifth  116  elements may all be of the prism type, described above having reflective surfaces oriented at about 45° to their respective optical axis, or of the mirror type described above, or any combination of the many different types of reflectors which may be used to accomplish the same object. In  FIG. 5 , the overall apparatus maybe for example about 60 mm in length, and width ______? The elements of module  100  may vary in spacing from about 20 to 35 mm, or in arrangement thereof, while not interfering with the effectiveness of the system. However, at spacing of about 33 mm has been found to be optimal for modules with many elements therein avoid convergence. The system  100  of optical elements, such as the combination of the second  106 , third  108 , fourth  114 , and fifth  116  elements, is used to create a folded optical path which may be repeated one, or multiple times, to generate increasingly long optical path lengths in one apparatus. 
         [0037]    In  FIG. 5 , the dual light paths  41 A and  41 B are incident on the first optical element  102  in the Y direction where it is reflected orthonormally toward the second optical element  106  in the X direction. The second optical element  106  will reflect incident light along the second column in the Y direction, towards the third optical element  108 . The third element  108  will reflect incident light from the second element  106  orthonormally toward the fourth element  114 , in the negative X direction. The fourth element  114  will reflect incident light along the third column  118  in the Y direction toward the fifth optical element  116 . The fifth optical element  116  will reflect light from the fourth element  114  in the X direction toward the sixth element  104 . The sixth element will reflect light from the fifth element  116 , in the Y direction for emission  16 / 23  from the module  100  to the eyepiece. 
         [0038]    In other embodiments, any number of elements may comprise other types of reflective elements such as mirrors, more preferably of the first-surface reflective type. For example, a first-surface reflector, oriented at approximately 45° to the direction of the light path, would reflect light in a desired direction within the module eliminating the phase transition of the light associated with prism type optical elements. In combination with one or more reflective or refractive elements, these reflectors may create a desired folded optical path for the module. 
         [0039]    In the preferred embodiment, which is  FIG. 3 , the elements  30  to  40  are approximately one inch in height, width and length. As such, they define an aperture one inch square which limits or stops down the beam of light transversing from the objective  14  to the eyepiece  16 . The optical elements  30  to  40  are located equally spaced apart in each column  41 ,  42  and, in each row, by 33 mm or less, but may be spaced otherwise than equi-distantly. It has bee found that a separation of about 33 mm between elements optimizes resolution of the image. The module  10  is therefore approximately 130 cm long by 105 cm wide. The elements  30  to  42  are mounted on a said frame  20  which is capable of supporting the elements, and are fastened to the frame  20  in a way which will retain the position of the elements, and preferably prevent any vibrations, or other mechanical disturbances of the elements. 
         [0040]    As described above, the optical module  10  or  100  are intended for use within an optical microscope  12 . The invention is inserted between an objective  14  and an eyepiece  16 . In a typical microscope  12 , light gathered from the sample by the objective  14 , would be propagated to the eyepiece  16  directly, in the embodiments described above, such light gathered by the objective, according to the strategy shown in  FIG. 2 , would be incident onto the first elements  30 / 102  of the module. The eyepiece  16  is then positioned to gather light emitted from the final elements  40 / 104  in the modules. In a preferred embodiment, the eyepiece  16  is in close proximity to the final elements  40 / 104 , while the objective  14  is located adjacent the first elements  30 / 102 . In other embodiments, for example, the light is projected from the objective  14  no more than 30 mm before it is incident on the first optical element  30 / 102  in the module  10  or  100 . The light beam is then bent at right angles, as set forth above. 
         [0041]    The configurations described above greatly enhance magnification [RW: By how much?] beyond what is provided by the objective  14  and eyepiece  16  as arranged in the optical microscope  12  without the module inserted therein. The optical microscope  12  can be used with microscopes that employ other specialized microscopy techniques such as fluorescent and polarization microscopy. 
         [0042]    Additionally, many of these modules  10  or  100  may be used in series to increase the magnification further. This series may comprise many modules, or a single module with, for example, a very long optical path.  FIG. 6  depicts a plurality of optical modules  10 / 100 , such as those described with reference to  FIGS. 3 and 5 , that are cascaded to provide a longer folded optical path between the objective  14  and the eyepiece  16 . 
         [0043]    Although described above in connection with particular embodiments of the present invention, it should be understood that the description to the embodiments are illustrative of the invention and are not intended to be limiting. Accordingly, various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the invention.