Patent Publication Number: US-2018045945-A1

Title: Monocular microscope for producing 3d image

Description:
TECHNICAL FIELD 
     The present application claims priority to Korean Patent Application No. 10-2015-0186866, filed Dec. 24, 2015, the entire contents of which is incorporated herein for all purposes by this reference. 
     The present invention relates generally to a monocular microscope for producing a 3D image and, more particularly, to a monocular microscope for producing a 3D image of a target having a fine size. 
     BACKGROUND ART 
     Generally, a microscope is an instrument used to magnify and observe tiny objects or microorganisms that are difficult to see with the naked eye. Nowadays, most conventional microscopes produce and display a 2D image of a target in real time. 
     However, in order to analyze a 3D structure of a detailed target, a microscope for producing a 3D image is required. In recent years, studies on a microscope magnifying and displaying a 3D image of a target have been in progress, thanks to the development of a 3D camera producing a 3D image. 
     Korean Patent No. 10-1476820 describes a conventional microscope producing and displaying an enlarged 3D image of a target. Referring to  FIG. 1 , the conventional microscope includes an achromatic prism  20  receiving incident beams from the target, and includes a pair of zoom lenses  30  adjusting magnification of the 3D image produced by the achromatic prism  20 . The zoom lenses  30  are provided at a rear surface of the achromatic prism  20 . 
     The achromatic prism  20  includes a first prism  21  having an angled structure protruding from the center thereof, and includes a second prism  22  having an angled concave structure at the center thereof. The achromatic prism  20  respectively transmits left-eye and right-eye images to a pair of image sensors  10 . That is, the conventional microscope disclosed in Korean Patent No. 10-1476820 adjusts magnification with the zoom lenses, but easily adjusts a convergence angle and the magnification by using the achromatic prism. 
     The conventional microscope disclosed in Korean Patent No. 10-1476820 easily can adjust the convergence angle and the magnification. However, as a microscope, when viewing a target that is very close, it is limited to secure the convergence angle due to two binocular lenses. 
     Specifically, the 3D camera provided in the microscope simultaneously captures left-eye and right-eye images of a target by using two cameras. A conventional 3D camera includes left-eye and right-eye cameras respectively capturing the left-eye and right-eye images, and further includes a 3D camera rig on which the left-eye and right-eye cameras are mounted. 
     The 3D camera rig is classified according to a parallel method (horizontal method) and an orthogonal method. A 3D camera rig using the parallel method mounts the left-eye and right-eye cameras parallel to each other. The left-eye and right-eye cameras are located to face the target, and are spaced apart from each other. The left-eye and right-eye cameras respectively receive beams reflected by the target. Therefore, 3D effect is expressed by the difference (hereinafter, denoted as binocular disparity) between the images respectively captured by the left-eye and right-eye cameras. 
     That is, in order to produce a 3D image by photographing a target with two cameras, it is required that minimum distances between the target and lenses of the two cameras are maintained due to a distance between the lenses of the two cameras. The minimum distance between the target and the lens is 30 or more times larger than a distance between the centers of the lenses of the two cameras. However, when a distance from the target to an objective lens is far, microscope magnification is limited. Therefore, typically, the microscope is not used for photographing a target that is far from the microscope. However, when the target is very close to lenses, it is impossible to produce a 3D image without a convergence angle. Even though a 3D image is produced, an observer may suffer from eye fatigue due to excessively expressed 3D effect of the 3D image. 
     Accordingly, use of a 3D camera, whereby the 3D image is formed combining the left-eye and right-eye images respectively captured by using two lenses, for a microscope is limited. The present applicant has upgraded the 3D camera using two lenses, and has proposed a monocular camera for producing a 3D image disclosed in Korean Patent No. 10-1255803. The monocular camera proposed by the present applicant can produce a clear 3D image by using one main lens (monocular lens). 
     Referring to  FIG. 2 , the conventional monocular camera for producing a 3D image described in Korean Patent No. 10-1255803 produces the 3D image by redirecting with a reflector  46 , beams separately to a left-eye camera  60  and a right-eye camera  62 , the beams obtained by one first imaging lens assembly  40 . That is, the conventional monocular camera for producing a 3D image uses one main lens (first imaging lens assembly). 
     However, in order to apply the conventional monocular camera for producing a 3D image to the microscope, the following technologies are required. 
     (1) A technology for close-up work, and (2) a technology for adjusting an angle of view based on magnification and de-magnification of the 3D image to produce a close-up 3D image, and (3) a technology for easily replacing and changing the first imaging lens assembly based on a position and characteristics of the target. 
     DOCUMENTS OF RELATED ART 
     Korean Patent No. 10-1476820 (3D video microscope). 
     Korean Patent No. 10-1255803 (monocular camera for producing 3D image). 
     DISCLOSURE 
     Technical Problem 
     Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and the present invention is intended to propose a monocular microscope for producing a 3D image of a target that is very close to a lens. 
     In addition, the present invention is intended to propose a monocular microscope for adjusting an angle of view based on magnification and de-magnification of an image of the target, the monocular microscope having a first imaging lens assembly easily replaced and changed. 
     Technical Solution 
     In order to achieve the above object, according to one aspect of the present invention, there is provided a monocular microscope including: a first imaging lens assembly  10 ; a half mirror H reflecting some of beams passing through the first imaging lens assembly  10 , and transmitting remaining thereof; second imaging lens assemblies  20 ,  21 , and  22  combined with the third imaging lens assemblies  31  and  41 , and adjusting focal points of the third imaging lens assemblies to be close to the respective third imaging lens assemblies, and magnifying a virtual image formed behind the first imaging lens assembly  10 , and reducing chromatic aberration or field curvature aberration, etc.; a first camera  30  including a third imaging lens assembly  31  forming an image by using the beams reflected by the half mirror H; and a second camera  40  including an additional third imaging lens assembly  41  forming an image by using the beams transmitted through the half mirror H. The third imaging lens assemblies  31  and  41  may be arranged to be spaced apart from each other at a right angle. In addition, the third imaging lens assemblies  31  and  41  may be freely arranged to be spaced apart from each other at an acute angle, which is less than 90 degrees, or at an obtuse angle, which exceeds 90 degrees. 
     The second imaging lens assemblies may be provided between the first imaging lens assembly  10  and the half mirror H, or between the half mirror H and the third imaging lens assemblies  31  and  41 . 
     When the third imaging lens assemblies  31  and  41  are macro lenses for close-up work, the second imaging lens assembly may be provided as an option. That is, when the third imaging lens assemblies  31  and  41  are macro lenses magnifying the virtual image formed behind the first imaging lens assembly enough to prevent vignetting, the second imaging lens assembly may be excluded from the monocular microscope. 
     When the third imaging lens assemblies  31  and  41  are telephoto lenses, the third imaging lens assemblies  31  and  41  may serve as macro lenses by combining the third imaging lens assemblies  31  and  41  with the second imaging lens assembly, thereby magnifying and producing an image passing through the first imaging lens assembly. Here, the magnification may be determined based on the size of the virtual image formed behind the first imaging lens assembly  10 , and on the size of image planes  36  and  46  respectively provided in the cameras  30  and  40 , and on an entire length (entire length of optical path from first imaging lens assembly to image plane) of the system. 
     According to another aspect, there is provided a monocular microscope including: a first imaging lens assembly  10 ; a half mirror H reflecting some of beams passing through the first imaging lens assembly  10 , and transmitting remaining thereof; a reflector reflecting at least one of the beams reflected by the half mirror H and the beams transmitted through the half mirror H, to make the reflected beams and the transmitted beams parallel to each other; a third imaging lens assembly  341  forming an image by using the beams reflected by the half mirror H; an additional third imaging lens assembly  331  forming an image by using the beams transmitted through the half mirror H, and provided to be parallel with the third imaging lens assembly  341 ; and a second imaging lens assembly magnifying and producing an image formed behind the first imaging lens assembly  10  by magnifying an image passing through the first imaging lens assembly  10  and by adjusting focal points of the third imaging lens assemblies to be close to the respective third imaging lens assemblies. 
     The second imaging lens assembly may be provided between the first imaging lens assembly  10  and the half mirror H, or between the half mirror H and the third imaging lens assemblies  331  and  341 . 
     When the third imaging lens assemblies  331  and  341  are macro lenses for close-up work, the second imaging lens assembly may be included in or excluded from the monocular microscope. 
     When the third imaging lens assemblies  331  and  341  are telephoto lenses, the third imaging lens assemblies  331  and  341  may serve as macro lenses by combining the third imaging lens assemblies  331  and  341  with the second imaging lens assembly, thereby magnifying and producing an image passing through the first imaging lens assembly. 
     In addition, the monocular microscope may use the monocular horizontal rig such that the beams reflected by the half mirror H are parallel to the beams transmitted through the half mirror H. However, the monocular microscope of the present invention may change the optical axes to be not parallel to each other by adjusting angles of the half mirror H and the reflectors. Consequently, it is possible to freely arrange the second imaging lens assemblies  21  and  22  to be not parallel to each other, as well as the third imaging lens assemblies  331  and  341  to be not parallel to each other. 
     In addition, the third imaging lens assemblies  331  and  341  may be provided in a single camera body  350 , or in respective camera bodies. 
     Advantageous Effects 
     The monocular microscope can realize various effects as follows. 
     First, the monocular microscope can produce a 3D image of a target that is very close to the first imaging lens assembly. 
     Second, the monocular microscope can adjust the angle of view based on the magnification and de-magnification of an image of the target that is very close to the first imaging lens assembly. 
     Third, the monocular microscope can provide a plurality of the first imaging lens assemblies that can be replaced and combined with the barrel such that it is easy to change and select the first imaging lens assemblies. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view showing the internal structure of a conventional microscope for producing a 3D image, and  FIG. 2  is a view showing the internal structure of a conventional monocular camera for producing a 3D image. 
         FIG. 3  is a view showing the internal structure of optical components of a monocular microscope according to a first exemplary embodiment of the present invention. 
         FIGS. 4 to 6  are views for explaining the role of a second imaging lens assembly of the monocular microscope of the present invention. 
         FIG. 7  is a view showing the internal structure of optical components of a monocular microscope according to a second exemplary embodiment of the present invention. 
         FIG. 8  is a view showing the internal structure of optical components of a monocular microscope according to a third exemplary embodiment of the present invention. 
         FIG. 9  is a view showing the internal structure of optical components of a monocular microscope according to a fourth exemplary embodiment of the present invention. 
         FIG. 10  is a cross-sectional view of a monocular microscope holding the optical components of  FIG. 3 , according to a fifth exemplary embodiment of the present invention. 
         FIG. 11  is a cross-sectional view of a monocular microscope holding the optical components of  FIG. 7 , according to a sixth embodiment of the present invention. 
     
    
    
     DESCRIPTION OF MAIN REFERENCE NUMERALS OF DRAWINGS 
     
         
         
           
               10 ,  50 ,  60 : First imaging lens assembly 
               20 ,  21 ,  22 : Second imaging lens assembly 
               30 : First camera 
               40 : Second camera 
               31 ,  41 : Third imaging lens assembly 
               35 ,  45 : Camera body 
               70 : Guide 
               100 ,  200 ,  300 ,  400 ,  500 ,  600 : Monocular microscope 
               510 ,  610 : Barrel 
               520 ,  620 : Support arm 
               530 ,  630 : Stage 
             H: Half mirror 
           
         
       
    
     MODE FOR INVENTION 
     Hereinbelow, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to the description, the terms and words used in the present specification and claims should not be interpreted as being limited to typical meanings or dictionary definitions, but should be interpreted as having meanings and concepts relevant to the technical scope of the present invention based on the rule according to which an inventor can appropriately define the concept of the term to describe most appropriately the best method he or she knows for carrying out the invention. Specific structural and functional descriptions of embodiments of the present invention disclosed herein are only for illustrative purposes of the exemplary embodiments of the present invention, and the present description is not intended to represent all of the technical spirit of the present invention. On the contrary, the present invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments that may be included within the spirit and scope of the present invention as defined by the appended claims. 
     According to the present invention, in order to produce a close-up 3D image, a monocular microscope includes a first imaging lens assembly  10 , a half mirror H, a first camera  30 , and a second camera  40 . After describing a structure of optical components provided at the inside of the monocular microscope, a mechanical configuration of the monocular microscope will be described. 
     Hereinafter, ‘an imaging lens assembly’ denotes an assembly combined with one or two or more lenses. 
     (1) First Exemplary Embodiment 
       FIG. 3  is a view showing the internal structure of optical components of a monocular microscope according to a first exemplary embodiment of the present invention. 
     Referring to  FIG. 3 , the monocular microscope  100  uses a monocular orthogonal rig. Therefore, the first camera  30  and the second camera  40  may be arranged to be spaced apart from each other at a right angle. Here, the right angle, without being limited to 90 degrees, includes a range of about 90 degrees. 
     Specifically, the monocular microscope  100  includes a first imaging lens assembly  10 , a second imaging lens assembly  20  provided behind the first imaging lens assembly  10 , a half mirror H, a first camera  30  provided on an optical axis reflected by the half mirror H, and a second camera  40  provided on an optical axis transmitted through the half mirror H. 
     Incident beams from a target  8  converge in the first imaging lens assembly  10 . The first imaging lens assembly  10  may be replaced with a suitable lens based on the purpose of use, the type of the target, a distance from the target to the first imaging lens assembly  10 , etc. In addition, the first imaging lens assembly  10  includes a zoom lens adjusting magnification. 
     The monocular microscope  100  may further include a second imaging lens assembly  20 . The second imaging lens assembly  20  adjusts focal points to be close to the respective third imaging lens assemblies by combining with third imaging lens assemblies  31  and  41 , and reduces both chromatic aberration and field curvature aberration. In addition, the second imaging lens assembly  20  is provided to move forward and backward on an optical axis between the half mirror H and the first imaging lens assembly  10 . Therefore, when producing a 3D image, the second imaging lens assembly  20  can assist the first imaging lens assembly  10  to focus on a target located beyond a focus range of the first imaging lens assembly  10 . When a main target is located slightly beyond the focus range of the first imaging lens assembly  10 , the main target can be focused by moving the second imaging lens assembly  20  toward the third imaging lens assemblies  31  and  41 . When the main target is located far beyond the focus range of the first imaging lens assembly  10 , the main target can be focused by moving the second imaging lens assembly  20  toward the first imaging lens assembly  10 . 
     The second imaging lens assembly  20  enables the monocular microscope  100  to produce a 3D image of the target that is very close to the first imaging lens assembly  10 . In addition, the second imaging lens assembly  20  enables the first imaging lens assembly  10  to precisely adjust an angle of view based on magnification and de-magnification of an image of the target regardless of the focus range. Here, when the distance between the target and the first imaging lens assembly  10  is less than 1 m, the target is very close to the first imaging lens assembly  10 . Even if the distance is less than 10 cm, the monocular microscope  100  can produce a clear 3D image. 
     The first camera  30  includes a third imaging lens assembly  31  and a camera body  35 . In addition, the second camera  40  includes an additional third imaging lens assembly  41  and an additional camera body  45 . The camera bodies  35  and  45  respectively include image planes  36  and  46  therein. 
     The third imaging lens assembly  31  forms an image by using the beams reflected by the half mirror H, and the additional third imaging lens assembly  41  forms an image by using the beams transmitted through the half mirror H. 
     The third imaging lens assemblies  31  and  41  serve as base lenses, and macro lenses may be used as the third imaging lens assemblies  31  and  41  for close-up work. In addition, when using the macro lenses as the third imaging lens assemblies  31  and  41  and enough magnification is obtained, the second imaging lens assembly  20  may be excluded from the monocular microscope. When using the macro lenses as the third imaging lens assemblies  31  and  41 , the monocular microscope can produce a 3D image of the organs, etc. that are very close to the first imaging lens assembly  10 . Furthermore, the monocular microscope can precisely adjust the angle of view based on the magnification and de-magnification of an image of the target that is located beyond the focus range of the first imaging lens assembly  10 . 
     When using telephoto lenses as the third imaging lens assemblies  31  and  41 , the third imaging lens assemblies  31  and  41  serve as macro lenses by being combined with the second imaging lens assembly  20 . With the combination, the monocular microscope can magnify and de-magnify an image of the detailed target, and enhances clarity of the 3D image by securing the convergence angle. 
     In order to use various lenses as a first imaging lens assembly  10 , it is desirable that a virtual image formed behind the first imaging lens assembly  10  is magnified by using the second imaging lens assembly  20  and the third imaging lens assemblies  31  and  41 . 
     To this end, when having a difficulty in adjusting both a distance between the third imaging lens assembly  31  and an image plane  36 , and another distance between the additional third imaging lens assembly  41  and an additional image plane  46 , the telephoto lenses are used as the third imaging lens assemblies  31  and  41 . In addition, the third imaging lens assemblies  31  and  41  are combined with the second imaging lens assembly  20  for close-up work. Therefore, it is possible to magnify the image formed by the first imaging lens assembly  10 . Alternatively, in order to adjust a focal point to be close to the respective third imaging lens assemblies, the macro lenses (close-up work lens) are used as the third imaging lens assemblies  31  and  41 , and additionally the second imaging lens assembly  20  is used. In addition, the second imaging lens assembly  20  reduces both chromatic aberration and field curvature aberration. Therefore, it is finally possible to magnify the virtual image formed behind the first imaging lens assembly  10  and produce the virtual image. 
     Particularly, when the sizes of the image planes  36  and  46  are larger than the size of a virtual image  9  of a first focal plane formed by the first imaging lens assembly  10 , the macro lenses are used as the third imaging lens assemblies  31  and  41  for close-up work. Therefore, it is possible to reduce vignetting. In addition, it is possible to provide a wide range of choices for the first imaging lens assembly  10 . 
     Moreover, in comparison with using telephoto lenses as the third imaging lens assemblies  31  and  41 , when using the macro lenses for close-up work as the third imaging lens assemblies  31  and  41 , the distance between the first imaging lens assembly  10  and the imaging planes  36  and  46  is shorter, thereby reducing the size of the monocular microscope. 
     In the meantime, in order to reduce the size of the monocular microscope, the second imaging lens assembly  20  may use a high magnification lens (lens having a short focal length). However, a high-definition image having low distortion can be produced by using a close-up work lens as the third imaging lens assemblies  31  and  41 , rather than using the high magnification lens as the second imaging lens assembly  20 . 
     In the meantime, the monocular microscope may further include apertures  32  and  42 . 
     The apertures  32  and  42  may be respectively provided in the third imaging lens assemblies  31  and  41 , without being provided in the first imaging lens assembly  10 . Even though a lens having an aperture is used as the first imaging lens assembly  10 , the aperture of the first imaging lens assembly  10  should stay open during photographing. The apertures  32  and  42  of the third imaging lens assemblies  31  and  41  prevent vignetting. 
     In the meantime, as described above, when using the macro lenses as the third imaging lens assemblies  31  and  41  and thus providing enough magnification, the second imaging lens assembly  20  may be excluded from the monocular microscope. When using the telephoto lenses as the third imaging lens assemblies  31  and  41 , the third imaging lens assemblies  31  and  41  serve as the macro lenses by being combined with the second imaging lens assembly  20 . In association with the above, the role of the second imaging lens assembly  20  will be described with reference to  FIGS. 4 to 6 . 
       FIGS. 4 to 6  are views showing the internal structure of the monocular microscope for explaining in detail the difference between using the monocular microscope with the second imaging lens assembly  20  and without, when the half mirror H and the first camera  30  are absent. 
       FIG. 4  is a view showing the case with the second imaging lens assembly  20 .  FIG. 5  is a view showing the case without the second imaging lens assembly  20 . The second imaging lens assembly  20  adjusts the focal point of the additional third imaging lens assembly  41  forward. Namely, the second imaging lens assembly  20  moves the focal point of the additional third imaging lens assembly  41  rightward in the drawing. Therefore, it is possible to reduce the length (length from first imaging lens assembly  10  to additional image plane  46 ) of the entire system (move the location of the first imaging lens assembly rightward in the drawing). 
     In other words, the focal point of the additional third imaging lens assembly  41  should be located at the position of the virtual image  9  of the first imaging lens assembly  10 . Therefore, the close-up work lens (for example, macro lens) is used as the additional third imaging lens assembly  41 . Alternatively, when a normal telephoto lens (lens having typical focal point control value) is used as the additional third imaging lens assembly  41 , the second imaging lens assembly  20  is also used, thereby adjusting the focal point of the additional third imaging lens assembly  41  forward. 
     In the case of  FIG. 4 , a normal image is formed. However, in the case of  FIG. 5 , an abnormal image is formed because the focal point of the additional third imaging lens assembly  41  is not located at the position of the virtual image  9  of the first imaging lens assembly  10 . In this case, as shown in  FIG. 6 , the first imaging lens assembly  10  is required to be located farther from the additional third imaging lens assembly  41 . When the first imaging lens assembly  10  is located farther from the additional third imaging lens assembly  41 , vignetting, which is a darkening at the periphery of an image caused by a reduced brightness around a camera lens, occurs. 
     (2) Second Exemplary Embodiment 
       FIG. 7  is a view showing the internal structure of optical components of a monocular microscope according to the second exemplary embodiment of the present invention. 
     Hereinafter, the same names are used throughout the monocular microscopes of the first and second exemplary embodiments to refer to the same components. Therefore, all same names have the same meanings, except for relationships between the components. 
     Referring to  FIG. 7 , a monocular microscope  200  uses a monocular orthogonal rig. Therefore, the first camera  30  and the second camera  40  may be arranged to be spaced apart from each other at a right angle. In addition, the first camera  30  and the second camera  40  may be freely arranged to be spaced apart from each other at an acute angle, which is less than 90 degrees, or at an obtuse angle, which exceeds 90 degrees. 
     Specifically, the monocular microscope  200  includes a first imaging lens assembly  10 , second imaging lens assemblies  21  and  22  provided behind the first imaging lens assembly  10 , a half mirror H, the first camera  30  provided on the optical axis reflected by the half mirror H, and the second camera  40  provided on the optical axis transmitted through the half mirror H. 
     In description of the difference between the monocular microscope  100  of the first exemplary embodiment and the monocular microscope  200  of the second exemplary embodiment, the second imaging lens assemblies  21  and  22  are respectively provided between the half mirror H and the third imaging lens assemblies  31  and  41 . Therefore, in the monocular microscope  200  of the second exemplary embodiment, the beams reflected by the half mirror H are incident to the third imaging lens assembly  31  via the second imaging lens assembly  21 . In addition, the beams transmitted through the half mirror H are incident to the additional third imaging lens assembly  41  via the second imaging lens assembly  22 . 
     In the meantime, according to the second exemplary embodiment of the present invention, the macro lenses or the telephoto lenses may be used as the third imaging lens assemblies  31  and  41 . In addition, when the macro lenses are used as the third imaging lens assemblies  31  and  41 , the second imaging lens assemblies  21  and  22  may be excluded from the monocular microscope. When the telephoto lenses are used as the third imaging lens assemblies  31  and  41 , the focal points can be adjusted to be close to the respective third imaging lens assemblies by combining the third imaging lens assemblies  31  and  41  with the second imaging lens assemblies  21  and  22 . Such descriptions of the monocular microscope  200  of the second exemplary embodiment are the same as those of the monocular microscope  100  of the first exemplary embodiment. 
     However, unlike the monocular microscope  100  of the first exemplary embodiment, it is desirable that the monocular microscope  200  of the second exemplary embodiment does not use devices frequently moving the second imaging lens assemblies  21  and  22  forward and backward on respective optical axes. The reason is that the loss of time for individually adjusting the focal points is greater than the benefit of focus range extension obtained by frequently moving the second imaging lens assemblies  21  and  22 . 
     (3) Third Exemplary Embodiment 
       FIG. 8  is a view showing the internal structure of optical components of a monocular microscope according to the third exemplary embodiment of the present invention. 
     Hereinafter, the same names are used throughout the monocular microscopes of the first and third exemplary embodiments to refer to the same components. Therefore, all same names have the same meanings, except for relationships between the components. 
     Referring to  FIG. 8 , according to the third exemplary embodiment, the monocular microscope  300  uses a monocular horizontal rig. In addition, the monocular microscope  300  includes the first imaging lens assembly  10 , and the half mirror H, the second imaging lens assemblies  21  and  22 , reflectors  361 ,  363  and  365  that are provided behind the first imaging lens assembly  10 . 
     The reflectors  361 ,  363  and  365  reflect at least one of the beams reflected by the half mirror H and the beams transmitted through the half mirror H, to make the reflected beams and the transmitted beams parallel to each other. 
       FIG. 8  shows an example of the reflectors. The reflectors  363  and  365  reflect the beams transmitted through the half mirror H toward an additional third imaging lens assembly  331 . In addition, the reflector  361  reflects the beams reflected by the half mirror H toward a third imaging lens assembly  341 . Here, the reflectors  361 ,  363  and  365  adjusting optical axes by reflecting the beams, without being limited to, may be mirrors. 
     According to the third exemplary embodiment, the monocular microscope  300  of  FIG. 8  uses the monocular horizontal rig such that the beams reflected by the half mirror H are parallel to the beams transmitted through the half mirror H. However, the monocular microscope of the present invention can change the optical axes to be not parallel to each other by adjusting angles of the half mirror H and the reflectors. Consequently, it is possible to freely arrange the second imaging lens assemblies  21  and  22  to be not parallel to each other, as well as the third imaging lens assemblies  331  and  341  to be not parallel to each other. 
     According to the third exemplary embodiment, some of beams passing through the first imaging lens assembly  10  pass through the half mirror H, and are incident to the second imaging lens assembly  21  by being reflected by the reflectors  363  and  365 . The remaining of the beams passing through the first imaging lens assembly  10  are reflected by the half mirror H and the reflector  361  in sequence, and are incident to the second imaging lens assembly  22 . 
     The beams incident to the second imaging lens assembly  21  are incident to the additional third imaging lens assembly  331  via the second imaging lens assembly  21 . The beams incident to the second imaging lens assembly  22  are incident to the third imaging lens assembly  341  via the second imaging lens assembly  22 . 
     In the meantime, according to the third exemplary embodiment of the present invention, the macro lenses or the telephoto lenses may be used as the third imaging lens assemblies  331  and  341 . In addition, when using the macro lenses as the third imaging lens assemblies  331  and  341 , the second imaging lens assemblies  21  and  22  may be excluded from the monocular microscope. When using the telephoto lenses as the third imaging lens assemblies  331  and  341 , the focal points can be adjusted to be close to the respective third imaging lens assemblies by combining the third imaging lens assemblies  331  and  341  with the second imaging lens assemblies  21  and  22 . Such descriptions of the monocular microscope  300  of the third exemplary embodiment are the same as those of the monocular microscope  100  of the first exemplary embodiment. 
     In the meantime,  FIG. 8  shows the monocular microscope using an integral binocular disparity type. Alternatively, using two cameras for the monocular microscope is well known to those of ordinary skill in the art. 
     (4) Fourth Exemplary Embodiment 
       FIG. 9  is a view showing the internal structure of optical components of a monocular microscope according to the fourth exemplary embodiment of the present invention. 
     Hereinafter, the same names are used throughout the monocular microscopes of the third and fourth exemplary embodiments to refer to the same components. Therefore, all same names have the same meanings, except for relationships between the components. 
     Referring to  FIG. 9 , a monocular microscope  400  of the forth exemplary embodiment is the same as a monocular microscope  300  of the third exemplary embodiment, except that the second imaging lens assembly  20  is provided in front of the half mirror H. Therefore, some of beams passing through the first imaging lens assembly  10  are reflected by the half mirror H and the mirror  361  in sequence, and are incident to the third imaging lens assembly  341 . The remaining of the beams passing through the first imaging lens assembly  10  pass through the half mirror H, and are reflected by the reflectors  363  and  365  in sequence, and are incident to the additional third imaging lens assembly  331 . 
     According to the fourth exemplary embodiment, the monocular microscope  400  of  FIG. 9  uses the monocular horizontal rig, such that the beams reflected by the half mirror H are parallel to the beams transmitted through the half mirror H. However, the monocular microscope of the present invention can change the optical axes to be not parallel to each other by adjusting angles of the half mirror H and the reflectors. Consequently, it is possible to freely arrange the third imaging lens assemblies  331  and  341  to be not parallel to each other. 
     In the meantime, according to the fourth exemplary embodiment of the present invention, the macro lenses or the telephoto lenses may be used as the third imaging lens assemblies  331  and  341 . In addition, when using the macro lenses as the third imaging lens assemblies  331  and  341 , the second imaging lens assembly  20  may be excluded from the monocular microscope. When using the telephoto lenses as the third imaging lens assemblies  331  and  341 , the focal points can be adjusted to be close to the respective third imaging lens assemblies by combining the third imaging lens assemblies  331  and  341  with the second imaging lens assembly  20 . Such descriptions of the monocular microscope  400  of the fourth exemplary embodiment are the same as those of the monocular microscope  100  of the first exemplary embodiment. 
     In the meantime, the monocular microscope  400  may use a binocular disparity type 3D camera (that is, integral binocular disparity type or two cameras) or a monocular horizontal rig. 
     (5) Fifth Exemplary Embodiment 
     Hereinafter, a mechanical configuration of the monocular microscope holding the above-mentioned structure of the optical components, will be described in detail by describing exemplary embodiments of the present invention. 
       FIG. 10  is a cross-sectional view of a monocular microscope holding the optical components of  FIG. 3 , according to the fifth exemplary embodiment of the present invention. 
     Referring to  FIG. 10 , according to the fifth exemplary embodiment of the present invention, the monocular microscope  500  includes first imaging lens assemblies  10 ,  50 , and  60 , a barrel  510 , a support arm  520 , and a stage  530 . 
     The first imaging lens assemblies  10 ,  50 , and  60  may be a plurality of the first imaging lens assemblies that are arranged to be spaced apart from each other. The barrel  510  may hold the half mirror H, the first camera  30 , and the second camera  40  therein. The barrel  510  may further hold the second imaging lens assembly  20  therein. The first imaging lens assemblies  10 ,  50 , and  60  may be provided at a lower part of the barrel  510 . Specifically, the first imaging lens assembly  10 , the second imaging lens assembly  20 , and the half mirror H may be arranged in sequence, along an optical axis of incident beams from the target  8 . 
     The support arm  520  may be connected to the barrel  510  to fix the position of the barrel  510  on the ground. A specimen of the target is placed on the stage  530 . The stage  530  may move in a horizontal direction, or may tilt by a method widely known in the art. 
     The monocular microscope may further include a guide  70 . The guide  70  moves the plurality of the first imaging lens assemblies  10 ,  50 , and  60  to alternately arrange one of the first imaging lens assemblies  10 ,  50 , and  60  to the lower part of the barrel  510 . A method of moving the first imaging lens assemblies  10 ,  50 , and  60  by the guide  70  includes a method of rotating a revolver. 
     The monocular microscope may further include a lighting device (not shown) provided at an outer surface of the first imaging lens assemblies  10 ,  50 , and  60 , the lighting device emitting beams to the target. The monocular microscope may further include another lighting device provided under the stage  530 , and emitting beams to the target. The lighting devices include lighting devices using a transmission method and a reflection method. 
     The 3D image produced by the first camera  30  and the second camera  40  that are provided in the barrel  510 , may be displayed on a display (not shown). 
     The structure of optical components of the monocular microscope  500  of the fifth exemplary embodiment is the same as those of the monocular microscope  100  of the first exemplary embodiment. 
     (6) Sixth Exemplary Embodiment 
       FIG. 11  is a cross-sectional view of a monocular microscope holding the optical components of  FIG. 7 , according to the sixth exemplary embodiment of the present invention. 
     Referring to  FIG. 11 , a monocular microscope  600  of the sixth exemplary embodiment is the same as a monocular microscope  500  of the fifth exemplary embodiment, except that the second imaging lens assemblies  21  and  22  are respectively provided between the half mirror H and the third imaging lens assemblies  31  and  41 . 
     In addition, it is apparent that the structures of optical components of the monocular microscopes  300  and  400  of the third and fourth exemplary embodiments can be applied to those of the monocular microscopes  500  and  600  of the fifth and sixth exemplary embodiments. 
     As described above, the monocular microscope of the present invention (1) can produce the 3D image of the target that is very close to the first imaging lens assembly, and (2) can adjust the angle of view based on magnification and de-magnification of the 3D image of the target that is very close to the first imaging lens assembly, and (3) can provide a plurality of the first imaging lens assemblies that can be replaced and combined with the barrel such that it is easy to change and select the first imaging lens assemblies.