Abstract:
A lens tube of a microscope comprises a plurality of observation ports, and first and second optical path switching means to be moved relatively to each other for switching an optical path to an arbitrary one of the observation ports upon the relative movement. The first optical path switching means is capable of switching for guiding light from a specimen to the second optical path switching means trough a first optical element owned by the first optical path switching means upon the relative movement or for guiding the light to the second optical path switching means without passing through the first optical element. The second optical path switching means is capable of switching for guiding the light from the first optical path switching means to an arbitrary one of the observation ports through a second optical element owned by the second optical path switching means upon the relative movement, or for guiding the light to an arbitrary one of the observation ports without passing through the second optical element.

Description:
[0001]     This application claims the benefit of Japanese Patent application No. 2003-366236 which is hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a lens tube of a microscope having a plurality of observation ports, and particularly, to optical path switching means to an observation port.  
         [0004]     2. Related Background Art  
         [0005]     Conventionally, a lens tube of a microscope having a plurality of observation ports is secured to the main body of the microscope through a circular dovetail, and an optical path switching unit for switching optical paths for a light coming from the main body of the microscope is provided above the circular dovetail. The optical path switching unit has a slide member which is supported to be movable by a guide, and this slide member is provided with three through holes for passing the light coming from the main body of the microscope therethrough. A prism is secured to each of the through holes. An operational lever for moving the slide member is secured to this slide member. It is arranged such that this operational lever is operated to switch to three observation ports to cause the light from the main body of the microscope to enter (see Japanese Patent No. 3318014, for example,  FIG. 1 ).  
         [0006]     However, the optical path switching unit of the lens tube of a microscope disclosed in Japanese Patent No. 3318014 requires a space for at least five optical paths including a retreat space of optical members only for sliding the slide member in the lateral direction when the optical path is switched to the three observation ports, which disadvantageously results in an increased size of the system.  
         [0007]     In consideration of the above problem, an object of the present invention is to provide a lens tube of a microscope having a small-sized optical path switching means.  
       SUMMARY OF THE INVENTION  
       [0008]     In order to achieve the above object, according to the present invention, there is provided a lens tube of a microscope comprising: a plurality of observation ports; and first and second optical path switching means to be moved relatively to each other for switching an optical path to an arbitrary one of the observation ports upon the relative movement, wherein the first optical path switching means is capable of switching for guiding light from a specimen to the second optical path switching means trough a first optical element owned by the first optical path switching means upon the relative movement or for guiding the light to the second optical path switching means without passing through the first optical element; and wherein the second optical path switching means is capable of switching for guiding light from the first optical path switching means to an arbitrary one of the observation ports through a second optical element owned by the second optical path switching means upon the relative movement, or for guiding the light to an arbitrary one of the observation ports without passing through the second optical element.  
         [0009]     According to the present invention, there is also provided a lens tube of a microscope comprising a plurality of observation ports and optical path switching means having optical elements for switching an optical path to the observation ports, wherein: the optical path switching means comprises: at least one lower holding member for holding the optical elements; a lower guide shaft for supporting the lower holding member to be movable; lower moving means for moving the lower holding member along the lower guide shaft; at least one upper holding member provided above the lower holding member to hold the optical elements; an upper guide shaft for supporting the upper holding member to be movable in the same direction as the lower holding member; upper moving means for moving the upper holding member along the upper guide shaft; and respective driving means for driving the lower moving means and the upper moving means.  
         [0010]     According to the present invention, there is further provided a lens tube of a microscope comprising a plurality of observation ports and optical path switching means having optical elements for switching an optical path to the observation ports, wherein: the optical path switching means comprises: at least one lower holding member for holding the optical elements; a lower guide shaft for supporting the lower holding member to be movable; lower moving means for moving the lower holding member along the lower guide shaft; at least one upper holding member provided above the lower holding member to hold the optical elements; an upper guide shaft for supporting the upper holding member to be movable in the same direction as the lower holding member; upper moving means for moving the upper holding member along the upper guide shaft; interlocking means for interlocking the movements by the lower moving means and the upper moving means along the lower guide shaft and the upper guide shaft with each other; and driving means for driving the lower moving means or the upper moving means, respectively.  
         [0011]     In the lens tube according to the present invention, it is preferable that the lower moving means comprises a lower cam follower which is disposed on the lower holding member and a lower cylindrical cam having a lower cam groove which is engaged with the lower cam follower and that the upper moving means comprises an upper cam follower which is disposed on the upper holding member and an upper cylindrical cam having an upper cam groove which is engaged with the upper cam follower.  
         [0012]     Also in the lens tube according to the present invention, it is preferable that the driving means is coupled to the lower cylindrical cam or the upper cylindrical cam.  
         [0013]     Also in the lens tube according to the present invention, it is preferable that the interlocking means comprises rotation transmitting means for interlocking a rotation of the lower cylindrical cam with a rotation of the upper cylindrical cam.  
         [0014]     Also in the lens tube according to the present invention, it is preferable that the driving means is a motor.  
         [0015]     According to the present invention, there is provided a microscope comprising the lens tube described above.  
         [0016]     According to the present invention, it is possible to provide a lens tube of a microscope having small-sized optical path switching means. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a schematic structural view of a microscope on which a lens tube for a microscope according to the present invention is mounted;  
         [0018]      FIG. 2  is a cross-sectional view of the lens tube of the microscope having optical path switching means according to a first embodiment of the present embodiment;  
         [0019]      FIGS. 3A, 3B  and  3 C are schematic structural perspective views of the optical path switching means according to the first embodiment of the present invention, for respectively showing optical path switched states;  
         [0020]      FIGS. 4A and 4B  are views for showing cross-sections taken along the line X-X in  FIG. 2 , in which  FIG. 4A  shows manual driving means and  FIG. 4B  shows driving means employing an electric motor;  
         [0021]      FIGS. 5A  to  5 C are schematic structural perspective views of the optical path switching means according to a second embodiment of the present invention, for respectively showing optical path switched states; and  
         [0022]      FIGS. 6A  to  6 C are schematic structural perspective views of the optical path switching means according to a third embodiment of the present invention, for respectively showing optical path switched states. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     Description will be made on an embodiment of a lens tube of a microscope according to the present invention, with reference to drawings.  
         [0024]      FIG. 1  is a schematic structural view of a microscope on which a lens tube of for a microscope according to the present invention is mounted.  FIG. 2  is a cross-sectional view of the lens tube for a microscope having optical path switching means according to the first embodiment of the present embodiment.  FIGS. 3A, 3B  and  3 C are schematic structural perspective views of the optical path switching means according to the first embodiment of the present invention, for respectively showing optical path switched states.  FIGS. 4A and 4B  are views for showing cross-sections taken along the line X-X in  FIG. 2 , in which  FIG. 4A  shows manual driving means and  FIG. 4B  shows driving means employing an electric motor.  FIGS. 5A  to  5 C are schematic structural perspective views of the optical path switching means according to the second embodiment of the present invention, for respectively showing optical path switched states.  FIGS. 6A  to  6 C are schematic structural perspective views of the optical path switching means according to the third embodiment of the present invention, for respectively showing optical path switched states.  
         [0025]     In  FIG. 1 , a lens tube  1  of a microscope having an optical path switching means according to an embodiment of the present invention is provided in an upper part of the main body  3  of a microscope. The lens tube  1  of the microscope is provided with an eyepiece observation unit  5 , and observation ports  9  and  11  each connected to a camera  7 .  
         [0026]     An illumination light beam from a lamp light source  13  enters a condenser lens  15  through an unrepresented illumination optical system, so as to illuminate an unrepresented specimen mounted on a stage  17 . The light beam from the specimen is condensed by an objective lens  20  which is attached to a revolving nosepiece  19  and then enters the lens tube  1 . The direction of the light beam entering the lens tube  1  is switched by the optical switching means which will be described later, so that the light beam can be observed by the eyepiece observation unit  5  or by an unrepresented monitor through the cameras  7  which are attached to the first observation port  9  and the second observation port  11 . In this manner, a microscope on which the lens tube  1  having the optical path switching means according to the embodiment of the present invention is constituted.  
         [0000]     (First Embodiment)  
         [0027]     Next, description will be made on the optical path switching means of the lens tube of a microscope according to the first embodiment of the present invention.  
         [0028]     In  FIG. 2  through  FIG. 4B , the lens tube  1  is connected to the microscope main body  3  through a circular dovetail coupling  21 . A first imaging lens  22  is secured to an upper part of the circular dovetail  21 , and the optical path switching means  23  which will be described later is provided above the first imaging lens  22 . A light beam which has passed through the first imaging lens  22  from the microscope main body  3  and has been deflected leftward in  FIG. 2  by the optical path switching means  23  passes through the second imaging lens  25  to advance to the eyepiece observation unit  5 . The light beam passing through the optical path switching means  23  progresses upward in  FIG. 2 , and passes through the third imaging lens  27  to advances to the first observation port  9 . The light beam deflected rightward in  FIG. 2  by the optical path switching means  23  passes through a zooming optical system  29  to advance to the second observation port  11 .  
         [0029]     As shown in  FIGS. 3A, 3B  and  3 C, the optical path switching means  23  is provided with a first holding member  33 , which is one of lower holding members, for holding an optical element constituted by a prism  31  and a prism  31   a  for discoloration and for adjustment of an optical path length bonded to each other and a second holding member  37  serving as the other of the lower holding members for holding a cylindrical glass  35  for adjusting the optical path length. The first and second holding members  33  and  37  are independently supported to be movable by guide shafts  40   a  and  40   b , respectively, so as to be movable in a range of the length of the guide shaft  40   a  or  40   b . Above the lower holding members, a third holding member  43  serving as an upper holding member for holding a mirror  41  is supported to be movable by the guide shafts  40   c ,  40   d  which are provided substantially parallel to the guide shafts  40   a ,  40   b . The guide shafts  40   a ,  40   b  and the guide shafts  40   c ,  40   d  are respectively secured to the lens tube  1  to be parallel to each other, and the length of each of the guide shafts is not greater than the width of the lens tube in the lateral direction, seen from the front of the lens tube  1 .  
         [0030]     A cam follower  45   a  is provided at an end of the first holding member  33 , a cam follower  45   b  (not shown) at an end of the second holding member  37 , and a cam follower  45   c  at an end of the third holding member  43 , respectively. Cam grooves  49   a ,  49   b  are formed on a first cylindrical cam  46 . The cam follower  45   a  is engaged with the cam groove  49   a , the cam follower  45   b  with the cam groove  49   b , and the cam follower  45   c  with a cam groove  49   c  formed on a second cylindrical cam  47 , respectively.  
         [0031]     As shown in  FIGS. 4A and 4B , the first cylindrical cam  46  and the second cylindrical cam  47  are coupled to each other by a timing belt  51  for interlocking rotations of the both cams. A switch dial  53  of driving means for driving the cylindrical cams  46 ,  47  is provided at one end of the second cylindrical cam  47 . When the switch dial  53  is rotated, the second cylindrical cam  47  rotates, and the first cylindrical cam  46  also rotates in an interlocking manner with a rotation of the second cylindrical cam  47  through the timing belt  51 .  
         [0032]     Upon rotations of the first cylindrical cam  46  and the second cylindrical cam  47 , the first to third holding members  33 ,  37  and  43  are moved along the guide shafts  40   a  to  40   d , respectively, through the cam followers  45   a ,  45   b  and  45   c  respectively engaged with the corresponding cam grooves  49   a ,  49   b  and  49   c , whereby the optical elements provided on the respective holding members are moved. The moving positions of the optical elements are controlled by the cam grooves  49   a ,  49   b  and  49   c . The optical path switching means is thus constituted.  
         [0033]     Note that the means for interlocking rotations of the first cylindrical cam  46  and the second cylindrical cam  47  is not limited to the timing belt  51 , but may be another member such as a gear. Also, as the driving means for driving each of the cylindrical cams, an electric motor  55  as shown in  FIG. 4B  may be employed, instead of the switch dial  53 . By the use of the electric motor  55 , switching of the optical paths to each observation port can be performed easily by operating an unrepresented switch. It is also possible to provide the driving means on the side of the first cylindrical cam  46 .  
         [0034]     According to the first embodiment, it is rendered possible to provide the respective optical elements at the predetermined positions by rotating the switch dial  53  or the electric motor  55  which serves as the driving means.  
         [0035]     Description will be made below on the layout of the optical elements (holding members) and an optical path switch state.  
         [0036]      FIG. 3A  shows a state in which the switch dial  53  is operated so that the first holding member  33  and the third holding member  43  are disposed on an optical path while the second holding member  37  is outside the optical path, and the prisms  31  and  31   a  and the mirror  41  are disposed on the optical path. A light beam from the first imaging lens  22  is divided by the prisms  31  and  31   a  into a leftward one and an upward one in the drawing. The light beam deflected leftward advances to the eyepiece observation unit  5  shown in  FIG. 2 , so as to be observed by an observer. The light beam advancing upward is deflected rightward in the drawing by the mirror  41  and passes through the zooming optical system  29  shown in  FIG. 2  to enter the second observation port  11  at which the light beam is subjected to image pickup by the camera  7  ( FIG. 1 ) to be observed by an unrepresented monitor or the like. In this manner, it becomes possible to observe an image both by the eyepiece observation unit  5  and the second observation port  11  at the same time.  
         [0037]      FIG. 3B  shows a state in which the switch dial  53  is operated so that all of the first to third holding members  33 ,  37  and  43  are retracted from the optical path. A light beam from the first imaging lens  22  progresses upward as it is without passing any prism or mirror of the optical path switching means  23  to enter the first observation port  9  shown in  FIG. 2 , at which the light beam is image-picked up by the camera  7  ( FIG. 1 ) and then is observed by the unrepresented monitor or the like.  
         [0038]      FIG. 3C  shows a state in which the switch dial  53  is operated so that the first holding member  33  is retracted from the optical path, and the second and third holding members  37  and  43  are disposed on the optical path. A light beam from the first imaging lens  22  is transmitted through the cylindrical glass  35  for adjusting the optical path length, is deflected rightward in the drawing by the mirror  41 , and is passed through the zooming optical system  29  shown in  FIG. 2  to enter the second observation port  11  at which the light beam is image-picked up by the camera  7  ( FIG. 1 ) and then observed by the unrepresented monitor or the like. Differing from the state in  FIG. 3A , all of the light beams from the first imaging lens  22  is reflected by the mirror  41  and then enter the second observation port  11  so that a brighter image can be picked up by the camera  7 .  
         [0039]     In the first embodiment, the second cylindrical cam  47  is rotated by the use of the switch dial  53  or the electric motor  5  provided on the optical path switching means  23 , the first cylindrical cam  46  is rotated through the timing belt  51 , and the first to third holding members  33 ,  37  and  43  are moved onto or retracted from the optical path through the cam followers  45   a ,  45   b  and  45   c  engaged with the cam grooves  49   a ,  49   b  and  49   c , respectively, whereby light beam entering from the microscope main body  3  through the first imaging lens  22  can be switched to the eyepiece observation unit  5 , the first observation port  9  and the second observation port  11 . A space required for the optical path switching means may include the spaces for the first and second holding members  33  and  37  and a retreat space, so that the optical path switching means  23  can be formed with a smaller space in the moving direction of the optical path switching means, compared with the conventional switching means.  
         [0000]     (Second Embodiment)  
         [0040]     Next, description will be made on an optical path switching means of a lens tube of a microscope according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in that a bonding surface between the prism  31  and the prism  31   a  is replaced by a mirror  131   a  and the prism  31   a  is removed. Other arrangements are the same as those in the first embodiment and are given the same referential numerals and symbols, and the description thereof will be omitted.  
         [0041]      FIG. 5A  shows a state in which the switch dial  53  is operated so that the first holding member  33  and the third holding member  43  are disposed on the optical path while the second holding member  37  is outside the optical path, and a prism  131  is disposed on the optical path. In an optical path switching means  123  according to the second embodiment, a light beam from the first imaging lens  22  enters the mirror  131   a  of the prism  131  and is totally reflected by the mirror  131   a  so as to be deflected leftward in the drawing to enter the eyepiece observation unit  5  shown in  FIG. 2 , at which the light beam is observed by the observant.  
         [0042]      FIG. 5B  shows a state in which the switch dial  53  is operated so that all of the first to third holding members  33 ,  37  and  43  are retracted from the optical path. A light beam from the first imaging lens  22  passes through the optical path switching means  123  as it is to progress upward to enter the first observation port  9  shown in  FIG. 2 , at which the light beam is image-picked up by the camera  7  ( FIG. 1 ) to be observed by the unrepresented monitor or the like.  
         [0043]      FIG. 5C  shows a state in which the switch dial  53  is operated so that the first holding member  33  is retracted from the optical path, and the second and third holding members  37  and  43  are disposed on the optical path. A light beam from the first imaging lens  22  is transmitted through the cylindrical glass  35  for adjusting the optical path length, is deflected rightward in the drawing by the mirror  41  to pass through the zooming optical system  29  shown in  FIG. 2 , and then enters the second observation port  11 , at which the light beam is image-picked up by the camera  7  ( FIG. 1 ) and then observed by the unrepresented monitor or the like.  
         [0044]     The optical path switching means  123  according to the second embodiment of the present invention can switch the light beam from the first imaging lens  22  to the eyepiece observation unit  5 , the first observation port  9  and the second observation port  11  so that all of the incident light beam can be directed to the corresponding ports. Other arrangements and effects are the same as those in the first embodiment and the description thereof will be omitted.  
         [0000]     (Third Embodiment)  
         [0045]     Next, description will be made on an optical path switching means of a lens tube of a microscope according to the third embodiment of the present invention. The third embodiment is different from the second embodiment in that the cylindrical glass  35  and the second holding member  37  with the cylindrical glass  35  mounted thereon are removed.  
         [0046]     Other arrangements are the same as those in the second embodiment and are given the same referential numerals and symbols, and the description thereof will be omitted.  
         [0047]      FIG. 6A  shows a state in which the switch dial  53  is operated so that the first holding member  33  and the third holding member  43  are disposed on the optical path and a prism  131  is disposed on the optical path. In an optical path switching means  223  according to the third embodiment, a light beam from the first imaging lens  22  enters the mirror  131   a  of the prism  131  and is totally reflected by the mirror  131   a  to be deflected leftward in the drawing to enter the eyepiece observation unit  5  shown in  FIG. 2 , at which the light beam is observed by the observant.  
         [0048]      FIG. 6B  shows a state in which the switch dial  53  is operated so that all of the first holding member  33  and the third holding members  43  are retracted from the optical path. A light beam from the first imaging lens  22  passes through the optical path switching means  223  as it is and progresses upward to enter the first observation port  9  shown in  FIG. 2 , at which the light beam is image-picked up by the camera  7  ( FIG. 1 ) and is observed by the unrepresented monitor or the like.  
         [0049]      FIG. 6C  shows a state in which the switch dial  53  is operated so that the first holding member  33  is retracted from the optical path and the third holding member  43  is disposed on the optical path. A light beam from the first imaging lens  22  is deflected rightward in the drawing by the mirror  41  to pass through the zooming optical system  29  shown in  FIG. 2 , and then enters the second observation port  11 , at which the light beam is image-picked up by the camera  7  ( FIG. 1 ) and then observed by the unrepresented monitor or the like.  
         [0050]     Since requiring no cylindrical glass for adjusting the optical path length, the optical path switching means  223  according to the third embodiment of the present invention can be manufactured at a lower cost because of the reduced constituted parts thereof. Other arrangements and effects are the same as those in the second embodiment and the description thereof will be omitted.  
         [0051]     In all of the foregoing embodiments, it is arranged such that the upper moving means and the lower moving means are interlocked with each other by the timing belt to be moved relatively to each other. However, it may be arranged such that the upper and lower moving means are moved independently of each other. In this case, no interlocking member is required, and the upper and lower moving means may be respectively provided with members such as a switch dial.  
         [0052]     In the present embodiment, the switch dial  53  is manually operated, as shown in  FIG. 4A  so as to move the respective holding members relative to each other. However, means for manual relative movement according to the present invention is not limited to this. Levers may be provided on the first and second optical path switching means, respectively, so as to move the respective optical path switching means along the lower and upper guide shafts independently of each other. In this case, it is effective if each lever is provided on an outer side surface of each of the first to third holding members so that the tip end portions of these levers are protruded outward from the lens tube and the protruded portions can be gripped by the user so that the user can insert or pull the levers into or out the lens tube. In this case, it is preferable that an indicative portion which indicates the positions of the levers and the layout of the optical elements is provided, for example, in the vicinity of the lever mounting portion on the outer wall of the lens tube so that the user can easily understand an inserting level or a pulling level of each lever into or from the lens tube and the positional relation among the respective optical elements. With such an indicative portion, the user can properly determine the layout of the optical elements when operating the levers by watching this indicative portion. As a result, the optical elements can be easily switched.  
         [0053]     Note that the foregoing embodiments are merely exemplary. The present invention is not limited to the structures and configurations described above. They can be properly altered or modified within the spirit and scope of the present invention.