Abstract:
An examination apparatus that has a simple structure and that is capable of determining the condition inside the apparatus and improving the ease of use of the apparatus when a specimen is changed is provided. The examination apparatus includes a stage on which a specimen is disposed; an optical system configured to form an enlarged or reduced image of the specimen; a cover configured to cover the stage and the optical system; an opening and closing member provided as part of the cover; a detection unit configured to detect whether the opening and closing member is in a closed state or an open state; and a stage driving unit configured to move the state. Only when the detection unit detects that the opening and closing member is open, the stage is moved by the stage driving unit to the outside of the cover through an opening covered by the opening and closing member.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an examination apparatus configured to display an enlarged or reduced image of a specimen and, more specifically, relates to an examination apparatus having a sealed box-shaped enclosure containing a space for disposing a specimen and an examination optical system. 
   This application is based on Japanese Patent Application No. 2005-294057, the content of which is incorporated herein by reference. 
   2. Description of Related Art 
   For an examination apparatus having a box-shaped enclosure accommodating a specimen and various essential components, such as an optical unit including objective lenses and a camera for capturing an observation image, an access door provided on a part of the box-shaped enclosure is opened and a specimen is manually disposed on a stage inside the box-shaped enclosure when the specimen is to be changed or when a new specimen is to be disposed. 
   In addition, a microscope apparatus allowing specimens to be changed easily has been proposed. 
   For example, the microscope apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2004-21006 has a specimen tray that automatically moves outside the apparatus by a one-touch operation. After a specimen is placed on the tray, the tray can be returned inside the apparatus by a one-touch operation. Therefore, the user can continue their examination without being disturbed by the process of changing the specimen. 
   However, the microscope apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2004-21006 is provided essentially for small specimens, such as prepared slides. When the concept of this invention is applied to an examination apparatus used for examining small animals, such as mice, the size of the tray has to be increased. Moreover, the size of the apparatus is increased because the XYZ driving range of the stage is increased. When the stage is driven, the tray is moved outside the apparatus from a slit provided in the box-shaped enclosure. Since the location of the slit cannot be changed, depending on the orientation of the microscope apparatus, the tray may project from the slit in a position that makes it difficult for the user to operate the apparatus. When a live specimen is to be examined, the user must check whether or not the condition of the specimen has changed during examination. However, for an apparatus that has a cover over the slit from which the tray is projected, the condition inside the apparatus cannot be observed during examination. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention has been conceived in light of the problems described above. Accordingly, it is an object of the present invention to provide an examination apparatus that has a simple structure and that is capable of determining the condition inside the apparatus and improving the ease of use of the apparatus when specimens are changed. 
   To achieve the above-described object, the present invention provides the following solutions. 
   The present invention provides an examination apparatus including a stage on which a specimen is disposed; an optical system configured to form an enlarged and reduced image of the specimen; a cover configured to cover the stage and the optical system; an opening and closing member provided as part of the cover; a detection unit configured to detect whether the opening and closing member is in a closed state or an open state; and a stage driving unit configured to move the stage. Only when the detection unit detects that the opening and closing member is open, the stage is moved by the stage driving unit to the outside of the cover through an opening covered by the opening and closing member. 
   According to the present invention, the stage driving unit may carry out an eject movement in which the stage is carried out from the inside of the cover to a first predetermined position outside the opening and may a return movement in which the stage is carried in from the outside of the opening to a second predetermined position inside the cover. 
   According to the present invention, the examination apparatus may further include a storage unit configured to store at least an eject position of the stage, and, when carrying the stage out to outside the cover, the stage may be carried out to the eject position stored in the storage unit. 
   According to the present invention, the examination apparatus may further include a storage unit configured to store at least a return position of the stage, and, when carrying the stage in to inside the cover, the stage is carried in to the return position stored in the storage unit. 
   According to the present invention, the examination apparatus may further include an anesthetic apparatus configured to anesthetize the specimen; a tube configured to supply anesthetic from the anesthetic apparatus to the specimen; an attachment member configured to attach the tube to the stage; and a holding member configured to hold the tube interposed between the attachment member and the anesthetic apparatus. The tube may be easily held by the holding member even when the eject movement and the return movement of the stage is being carried out. 
   According to the present invention, the holding member may be a rotary wind-up mechanism. 
   According to the present invention, in the examination apparatus according to an embodiment of the present invention, a specimen is disposed in a sealed space and is examined from the outside, and access to the inside of the apparatus is restricted by an access door. The movement range of an XY stage holding the specimen is extended outside an opening that can be left open or covered in the exterior of the apparatus. By automatically moving the XY stage to outside the opening, the user can easily change the specimen, dispose a new specimen, and treat the specimen. Since the XY stage can be quickly returned to the examination position, various different specimens can be examined quickly and easily. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  illustrates the overall structure of an examination apparatus according to a first embodiment of the present invention. 
       FIGS. 2A to 2D  illustrate the structure of an access door and the area therearound of the examination apparatus shown in  FIG. 1 . 
       FIG. 3A  illustrates the structure of an XY stage of the examination apparatus illustrated in  FIG. 1 , and  FIG. 3B  illustrates the XY stage at an eject position. 
       FIG. 4  illustrates the structure of a wind-up mechanism near the XY stage of the examination apparatus illustrated in  FIG. 1 . 
       FIG. 5A  illustrates the overall structure of a stage controller of the examination apparatus illustrated in  FIG. 1 , and  FIG. 5B  illustrates parameters corresponding to the movement range of the XY stage. 
       FIG. 6  illustrates a graphical user interface (GUI) of a control application of the examination apparatus illustrated in  FIG. 1 . 
       FIG. 7  is a flow chart showing the operation of the main components of the examination apparatus illustrated in  FIG. 1 . 
       FIG. 8  is a flow chart showing the operation of the main components of the examination apparatus illustrated in  FIG. 1 . 
       FIG. 9  is a flow chart showing the operation of the main components of a first modification of the examination apparatus illustrated in  FIG. 1 . 
       FIG. 10  illustrates an operating unit of the examination apparatus illustrated in  FIG. 1 . 
       FIG. 11  is a flow chart showing the operation of the main components of a second modification of the examination apparatus illustrated in  FIG. 1 . 
       FIGS. 12A to 12D  illustrate a sliding window and the area therearound in an examination apparatus according to a second embodiment of the present invention. 
       FIG. 13  is a flow chart showing the operation of the main components of the examination apparatus illustrated in  FIGS. 12A to 12D . 
       FIG. 14  is a flow chart showing the eject process using the sliding window in the examination apparatus illustrated in  FIGS. 12A to 12D . 
       FIG. 15  is a flow chart continuing from the flow chart in  FIG. 14 . 
       FIG. 16  is a flow chart showing the return process using the sliding window in the examination apparatus illustrated in  FIGS. 12A to 12D . 
       FIG. 17  illustrates a modification of the wind-up mechanism of the examination apparatus illustrated in  FIG. 1 . 
       FIGS. 18A to 18C  illustrate another modification of the wind-up mechanism of the examination apparatus illustrated in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   An examination apparatus according to a first embodiment of the present invention will be described below with reference to  FIGS. 1 to 8 . 
   As shown in  FIG. 1 , the examination apparatus according to this embodiment includes an examination apparatus main body  1 , a system controller  2 , and a stage controller  3  that are connected to the examination apparatus main body  1  via cables  21  and  22 , respectively, and a computer  5  that is connected to the system controller  2  and the stage controller  3  via RS232 cables  23  and  24 , respectively. 
   The examination apparatus includes an illumination device  4  configured to supply illumination light through an optical fiber  25 . The illumination device  4  includes a lamp  101  that is the light source, excitation filters  102  that transmit only light having a wavelength within a predetermined wavelength band, and a shutter  103  for blocking the illumination light. One of the excitation filters  102  can be disposed on the optical axis. The illumination device  4  is connected to the computer  5  via a LAN cable  26  and can be controlled by the computer  5 . A digital camera  9  including a charge-coupled device (CCD) is disposed inside the examination apparatus main body  1  as an examination-image capturing unit. The digital camera  9  is connected to the computer  5  via a cable  27 . 
   The examination apparatus main body  1  is entirely covered with an exterior case  6  so as to shut out light (i.e., outside light). The exterior case  6  has an access door  7 . By opening the access door  7 , the area inside the examination apparatus main body  1  and an XY stage  8  disposed therein can be accessed. On the XY stage  8 , a specimen  11  to be examined is disposed. The XY stage  8  is driven by the system controller  2  in the vertical direction for focusing and is driven by the stage controller  3  in a plane parallel to the stage surface. 
   Excitation light from the illumination device  4  guided through the optical fiber  25  into the examination apparatus main body  1  is collimated by a lens group  12 . The collimated excitation light is reflected downward along the optical axis M by a cube  13 . The cube  13  includes a typical dichroic mirror. The excitation light reflected downward is focused by an objective lens  14  and is incident on the specimen  11 . Fluorescence is generated when the excitation light is incident on the specimen  11 . An imaging lens  15  forms a fluorescent image on the CCD surface of the digital camera  9  through the objective lens  14  and the cube  13 . In this way, the fluorescence image of the specimen  11  formed on the CCD surface is shown on the display of the computer  5 . 
   A plurality of cubes  13  is provided on a rotary turret (not shown in the drawings), and one of these cubes  13  is selectively disposed in the optical path. Similarly, a plurality of objective lenses  14  is provided on a rotary mechanism (not, shown), and one of these objective lenses  14  is selectively disposed in the optical path. The rotary turret for the cubes  13  and the rotary mechanism for the objective lenses  14  are controlled by the system controller  2 . An anesthetic apparatus  10  supplies anesthetic gas, which is a gaseous form of liquid anesthetic, to the specimen  11  through an anesthetic tube  28 . 
   The access door  7  and the area around the access door  7  will be described with reference to  FIGS. 2A to 2D . 
   The access door  7  has a micro switch  201  for detecting whether the access door  7  is open or closed. In  FIG. 2A , the access door  7  is at a closed position, whereas in  FIG. 2B , the access door  7  is at an open position. 
   The micro switch  201  is urged upward with a spring. When the access door  7  is not disposed above the micro switch  201  ( FIG. 2C ), the micro switch  201  projects outward from a hole provided in the exterior case  6 , turning the micro switch  201  off. When the access door  7  gradually closes and comes into contact with the micro switch  201 , the micro switch  201  is pushed into the exterior case  6  by the pressing force receive thereby. When the access door  7  is closed further and reaches a predetermined position, the micro switch  201  is turned on. The closed and open positions of the access door  7  are detected through the on and off states of the micro switch  201 . 
   The micro switch  201  is adjusted such that the access door  7  has to be opened by almost 90°, as shown in  FIG. 2C , unlike  FIG. 2A  where the access door  7  is only slightly open, to be detected as being open. The micro switch  201  and the XY stage  8  are electrically connected so that a switch ON/OFF signal is transmitted to the stage controller  3  via the XY stage  8 . 
     FIGS. 3A and 3B  illustrate details of the XY stage  8 . 
     FIG. 3A  illustrates the XY stage  8  positioned near the origin in the Y direction.  FIG. 3B  illustrates the XY stage  8  being moved to a position forward of that illustrated in  FIG. 3A  (i.e., moved in the positive Y direction). In this embodiment, an electrically operated XY stage is provided above a focusing unit (not shown in the drawing). 
   The XY stage  8  is moved in the X direction (i.e., front and back direction when the examination apparatus is viewed from the front) by moving a stage plate  301  on which a specimen is disposed along rails  303  mounted on a base  302 . A stage supporting plate  313  is disposed on the rails  303 . The stage plate  301  is screwed onto the stage supporting plate  313 . 
   To actually move the XY stage  8 , a standard ball screw mechanism (not shown in the drawings) is used to drive the XY stage  8  with an X-axis motor  304 . The movement range in the X direction is controlled by limit sensors  305   a  and  305   b . The movement in the negative X direction in the drawing is limited by the limit sensor  305   a , whereas the movement in the positive X direction is limited by the limit sensor  305   b . A circular region  314  having the same dimensions as the outline of the examination field when the objective lens  14  having the lowest magnifying power is located in the optical path is marked on the stage plate  301 . The center of the circular region  314  is aligned with the center of the examination field obtained when the XY stage  8  is moved to a home position, which is described below. 
   The XY stage  8  is moved in the Y direction (i.e., left and right direction when the examination apparatus is viewed from the front) by moving the entire assembly on the base  302  along rails  307  mounted on a base  306 . To actually move the XY stage  8 , similar to the movement in the X direction, a standard ball screw mechanism (not shown in the drawings) is used to drive the XY stage  8  with a Y-axis motor  308 . 
   For the movement range in the Y direction, the movement in the negative Y direction in the drawing is limited by the limit sensor  309   a , whereas the movement in the positive Y direction is limited by the limit sensor  309   b . The limit sensors  305   a ,  305   b ,  309   a , and  309   b  are photo interrupter sensors and detect the limits in corresponding directions by means of sensor blocking plates (not shown in the drawings) disposed on the stage plate  301  and the base  302 . 
   The detection outputs from the limit sensors  305   a ,  305   b ,  309   a , and  309   b  are sent to the stage controller  3 . When any one of the limit sensors  305   a ,  305   b ,  309   a , and  309   b  is turned on, movement in the direction corresponding to the turned on limit sensor is stopped. A control connector  311  and a switch input connector  312  are provided as interfaces with external equipment and are connected to the stage controller  3  and the micro switch  201 , respectively, for data transmission. 
   A fixing unit  310  for fixing a first end of the anesthetic tube  28  used to anesthetize the specimen  11  is disposed on the stage plate  301 . In this way, anesthetic gas sent from the anesthetic apparatus  10  can be supplied to the XY stage  8 . The anesthetic tube  28  fixed by the fixing unit  310  is wound around a wind-up mechanism, described below, and a second end of the anesthetic tube  28  is connected to the anesthetic apparatus  10 . 
     FIG. 3B  illustrates the XY stage  8  being positioned at the limit position in the positive Y direction (i.e., a state in which the limit sensor  309   a  is turned on). As shown in the drawing, the stage plate  301  is mounted in such a way that it can be moved to a position that is outside the opening of the access door  7  when the access door  7  is opened. 
     FIG. 4  illustrates the wind-up mechanism of the anesthetic tube  28 . 
   A bobbin-shaped reel  333  is rotatably attached to a fixed end  332  inside the examination apparatus main body  1 . The rotary shaft of the reel  333  is hollow, and the anesthetic tube  28  is passed through the rotary shaft toward the anesthetic apparatus  10 . 
   One end of a spring  331  is fixed to the fixed end  332 , and the other end of the spring  331  is fixed to the reel  333 . In this state, by rotating the reel  333  with respect to the fixed end  332 , a repulsive force caused by the spring is applied in the direction opposite to the rotation. By winding the anesthetic tube  28  around the reel  333  at a position where repulsive force of the spring is not applied, when the anesthetic tube  28  is pulled out in the direction of the fixing unit  310 , a force equivalent to force applied when pulling out the anesthetic tube  28  is applied to the reel  333 . In this way, tension is constantly applied to the section of the anesthetic tube  28  between the fixing unit  310  and the wind-up mechanism, preventing the anesthetic tube  28  from becoming slack. 
   The anesthetic tube  28  wound around the reel  333  when the fixing unit  310  is moved closest to the wind-up mechanism, within the movement range of the XY stage  8 , has a length that is sufficient even when the XY stage  8  is pulled out to a position where the distance between the fixing unit  310  and the wind-up mechanism is at the maximum extent within the movement range of the XY stage  8 . 
     FIG. 5A  illustrates the structure of the stage controller  3 . 
   As shown in the drawing, motor drivers  401   a  and  401   b  for driving an X-axis motor and a Y-axis motor of the XY stage  8  are connected to a microcomputer  402 . A ROM  403  for storing programs for operating the microcomputer  402 , a RAM  404  used as a work area when a program is executed, and an NVRAM  405  for saving values such as drive parameters while the power is turned off are connected to the microcomputer  402 . 
   A stage connector  406  is provided as an interface for the XY stage  8 . The motor driver  401   a  for the X-axis motor and the motor driver  401   b  for the Y-axis motor are connected to the stage connector  406 . Also, the microcomputer  402  is connected to the stage connector  406  to receive sensor signals from sensors disposed on the XY stage  8 . 
   The microcomputer  402  manages the stage position coordinates and limits the movement range of the XY stage  8  by storing movement-restricting coordinates in the ROM  403  or the NVRAM  405  of the stage controller  3 . In this way, the movement range of the XY stage  8  may be limited according to whether the access door  7  is open or closed. 
   As shown in  FIG. 5B , when the access door  7  is open, coordinates corresponding to the entire movement range of the XY stage  8  are set. When the access door  7  is closed, a movement range that prevents the XY stage  8  from coming into contact with the closed access door  7  is defined by coordinates. 
   An RS232C connector  407  is provided as an interface for connecting the computer  5 , such as a personal computer, to the microcomputer  402 . The RS232C connector  407  enables the microcomputer  402  is capable of communicating with the computer  5  via the RS232C cable  24  so as to receive information on the motor control for the X and Y axes and the coordinates. An HS connector  408  is connected to an operating unit  30  for operating the XY stage  8 . 
     FIG. 6  illustrates a GUI of a control application for the examination apparatus main body  1  displayed on a screen of the computer  5 . 
   A live image display screen  801  constantly displays the examination image captured by the digital camera  9 . Magnification switching buttons  802   a  to  802   e  correspond to the objective lenses  14  and are used to select one of the objective lenses  14  that has a specific magnifying power and that is to be disposed in the optical path. Examination-method switching buttons  803   a  to  803   c  correspond to the cubes  13  and are used to select which examination method (e.g., bright-field examination or fluorescence examination (for fluorescence examination, a dye is selected)) is to be employed for examining the specimen  11 . 
   Focus buttons  806   a  and  806   b  correspond to the movement of the XY stage  8  in the upward and downward direction (i.e., Z direction) and is used to focus the examination image. 
   Stage operating buttons  804   a  to  804   h  are used to move the XY stage  8  in eight different directions within a plane parallel to the surface of the XY stage  8 . An eject/return (E/R) button  805  is used to move the XY stage  8  to predetermined positions. When the E/R button  805  is operated, the XY stage  8  is ejected from the examination position to a position where the specimen  11  can be easily changed, a new specimen  11  can be easily disposed, or an intravenous injection can be easily carried out on the specimen  11 , or the XY stage  8  is returned to the examination position. 
   The eject and return processes are carried out alternately each time the E/R button  805  is operated. When the XY stage  8  is at the eject position, the return process is carried out when the E/R button  805  is operated, whereas when the XY stage  8  is at the examination position, the eject process is carried out when the E/R button  805  is operated. When the return process is carried out, the XY stage  8  is returned to one of two different positions: the position of the XY stage  8  where the eject command was received (full return process); and the position of the XY stage  8  where a predetermined area of the XY stage  8  is positioned at the center of the examination field (hereinafter, this position is referred to as a “home position,” and this operation is referred to as a “home return process”). The commands for a full return process and a home return process are distinguished by clicking the E/R button  805  once or clicking the E/R button  805  twice within a predetermined amount of time (i.e., double-clicking). 
   Fine/coarse movement switching buttons  807  and  808  are disposed near the focus buttons  806   a  and  806   b  and the stage operating buttons  804   a  to  804   h . The fine/coarse movement switching button  807  is used to change the movement speed of the XY stage  8  in the Z direction and is used to switch between a coarse movement mode and a fine movement mode. The fine/coarse movement switching button  808  is used to change the movement speed of the XY stage  8  in the XY directions. 
   Next, the operation of the examination apparatus according to this embodiment, having the above-described structure, will be described with reference to the flow chart in  FIG. 7 . 
   When the E/R button  805  on the application GUI is clicked in Step  601  in  FIG. 7 , in Step  602 , it is determined whether or not the XY stage  8  is currently at a return position (examination position). Here, when it is determined that the XY stage  8  is at the return position, the eject process is started. When it is determined that the XY stage  8  is not at the return position, the return process is started (refer to  FIG. 8 ). 
   In Step  603 , it is determined whether or not the access door  7  is open on the basis of the on or off state of the micro switch  201 . When it determined that the access door  7  is open, in Step  604 , the coordinates for the current position of the XY stage  8  are stored in a storage device (e.g., hard disk or memory) in the computer  5 . Here, the XY coordinates are obtained from the stage controller  3  and the Z coordinate is obtained from the system controller  2 . Next, in Step  605 , the coordinates (X, Y, Z) corresponding to a predetermined eject position are read out. 
   The coordinates for the eject position are stored in the storage device of the computer  5 . When the access door  7  is not open, in Step  616 , a dialog instructing the user to open the access door  7  so that the XY stage  8  can be ejected is displayed. When the user opens the access door  7  at this point (“yes”, in Step  651 ), the process proceeds to Step  604  to continue the eject process. 
   When the user does not open the access door  7  and issues a cancel command (“yes”, in Step  652 ), the process is terminated without carrying out the eject movement. 
   In Step  606 , the XY stage  8  is moved in the XY directions toward the eject position. While the XY stage  8  is moving, in Step  607 , the XY stage  8  is constantly checked to determine whether or not it has reached the eject position. In Step  609 , when a button on the application GUI is operated, in Step  610 , the movement of the XY stage  8  is stopped, and the eject process is aborted. 
   When the XY stage  8  reaches the eject position in Step  607 , the movement of the XY stage  8  is stopped in Step  608 , and the eject movement in the XY directions is completed. Next, the eject movement in the Z direction is carried out. In Step  611 , the XY stage  8  is moved in the Z direction on the basis of a command sent via the system controller  2 . Similar to the eject movement in the XY directions, while the XY stage  8  is moving, in Step  612 , the XY stage  8  is constantly checked to determine whether or not it has reached the eject position. 
   In Step  614 , when a button on the application GUI is operated, in Step  615 , the movement of the XY stage  8  in the Z direction is stopped, and the eject process is aborted. When the XY stage  8  reaches the eject position in Step  612 , the movement of the XY stage  8  in the Z direction is stopped in Step  613 , and the eject process in the Z direction is completed. This completes the entire eject process. 
   Only when the entire eject process is completed, is the current condition of the XY stage  8  (i.e., return or eject position of the XY stage  8 ) changed to “ejected state.” In other words, when the eject process is aborted in Step  609  or  614  by operating a button, the current stage condition will remain in “return state,” which is the condition the XY stage  8  was in when the eject process was started. 
   Next, the return process will be described with reference to  FIG. 8 . 
   In Step  621 , it is determined whether or not the E/R button  805  was double-clicked in Step  601 . When it is determined that the E/R button  805  was double-clicked, in Step  622 , the predetermined home position coordinates (stored in the storage device of the computer  5 ) are read out. Here, the read-out X and Y coordinates are the coordinates for the predetermined home position, and the Z coordinate is the coordinate for an eject position stored when the XY stage  8  was last ejected. 
   In Step  621 , when it is determined that the E/R button  805  was not double-clicked (i.e., the E/R button  805  was clicked only once), in Step  623 , the stored coordinates (X, Y, Z) for the position of the XY stage  8  at the point when the eject process is instructed are read out. 
   Next, in Step  624 , the XY stage  8  is moved toward the return position in the Z direction. While the XY stage  8  is moving, in Step  625 , the XY stage  8  is constantly checked to determine whether or not it has reached the return position in the same manner as in the eject process. When a button on the application GUI is operated in Step  627 , the movement of the XY stage  8  in the Z direction is stopped in Step  628 , and the return process is aborted. In Step  625 , when the XY stage  8  reaches the return position, the movement of the XY stage  8  in the Z direction is stopped in Step  626 , and the return movement in the Z direction is completed. 
   Next, the return movement in the XY directions will be described. 
   In Step  629 , the XY stage  8  is moved in the XY directions toward the return position. In the same way as in the eject process, while the XY stage  8  is moving, in Step  630 , the XY stage  8  is constantly checked to determine whether or not it has reached the return position. When a button on the application GUI is operated in Step  632 , the movement of the XY stage  8  in the XY directions is stopped in Step  633 , and the return process is aborted. 
   In Step  630 , when the XY stage  8  reaches the return position, the movement of the XY stage  8  in the XY directions is stopped in Step  631 , and the return movement in the XY directions is completed. In this way, the entire return process is completed. Only when the entire return process is completed, the current condition of the XY stage  8  (i.e., return or eject position of the XY stage  8 ) is changed to the “return state.” In other words, when the return process is aborted by operating a button in Step  627  or  632 , the current stage condition will remain in the “ejected state,” which is the condition the XY stage  8  was in when the return process was started. 
   In the examination apparatus according to the first embodiment, the specimen  11  is disposed in a sealed space and is examined from the outside. Access to the specimen  11  is limited by the access door  7 . The movement range of the XY stage  8  on which the specimen  11  is disposed is extended outside the opening of the access door  7  when the access door  7  is open. Whether the access door  7  is open or closed is detected to automatically move the XY stage  8  outside through the opening. In this way, the user can easily change the specimen  11 , dispose a new specimen, and treat the specimen  11 . Since the XY stage  8  can be quickly returned to the examination position, various different specimens can be examined quickly and easily. 
   According to this embodiment, the access door  7  limiting access to the specimen  11  is a door that can be pulled open. However, the access door  7  may be a shutter that is slid open. In the above, the access door  7  is a door that opens from the left side. However, the same advantages are achieved regardless of the direction (left, right, up, or down) from which the access door  7  is opened. 
   In the above, the eject position is a predetermined fixed position. Instead, however, the eject position may be changed. This is possible by modifying the return process in  FIG. 8  to the process shown in  FIG. 9 . 
   The steps in the process shown in  FIG. 9  that are the same as those in  FIG. 8  are indicated by the same reference numbers, and descriptions thereof are not repeated. When the E/R button  805  is operated to start the return process, in Step  641 , it is determined whether or not the coordinates (X, Y, Z) for the current position of the XY stage  8  match the coordinates for the predetermined eject position. In other words, it is determined whether the user has already executed the eject process and the XY stage  8  has been moved from the eject position. Here, when it is determined that the current position and the predetermined eject position match, the process proceeds to Step  621 , and the subsequent steps are carried out in the same manner as the steps in  FIG. 8 . 
   In Step  641 , when it is determined that the current position does not match the predetermined eject position, in Step  642 , a message is displayed to ask the user to decide whether or not to set the current position as the eject position. In Step  643 , when the user decides not to set the current position as the eject position, the process proceeds to Step  621 . When the user decides to set the current position as the eject position, the process proceeds to Step  644  so as to store the coordinates (X, Y, Z) for the current position as coordinates for the eject position. The subsequent steps are the same as those in  FIG. 8 , and descriptions thereof are not repeated. 
   According to this embodiment, the eject and return positions are set three-dimensionally. However, the XY stage  8  may be moved two-dimensionally, and the eject and return positions may be set two-dimensionally. The XY stage  8  can be moved two-dimensionally and the eject and return positions can be set two-dimensionally by carrying out the same process as in  FIGS. 7 and 8 , except for the steps related to the movement in the Z direction (which are Steps  611  to  615  in  FIG. 7  and Steps  624  to  628  in  FIG. 8 ). 
   When the eject and return positions are set two-dimensionally, the XY stage  8  can be operated through the operating unit  30  connected to the stage controller  3 . In this way, the same advantages as described above are achieved without using an application GUI of the computer  5 . 
     FIG. 10  illustrates the structure of the operating unit  30 . 
   A joystick  501  and directional keys  502   a ,  502   b ,  502   c , and  502   d  are used to move the XY stage  8  in the X and Y directions. When the joystick  501  is used for operation, the speed of the stage movement can be changed in accordance with the tilt of the stick. The larger the tilt of the joystick  501  is with respect to its vertical position, the greater the speed of the stage movement is. When the XY stage  8  is operated with the directional keys  502   a ,  502   b ,  502   c , and  502   d , the speed of the stage movement is constant. 
   A fine/coarse movement switching button  503  switches the speed of the stage movement (i.e., switches between a coarse movement mode and a fine movement mode) controlled by the joystick  501  and the directional keys  502   a ,  502   b ,  502   c , and  502   d . In the coarse movement mode, the speed of the stage movement is, for example, ten times greater than the speed of the stage movement in the fine movement mode. An E/R button  504  has the same configuration as the E/R button  805  on the application GUI. A display unit  505  displays information on the coordinates of the XY stage  8 , the speed of the XY stage  8 , and the movement (i.e., return movement or eject movement) being carried out. A connector  506  is connected to the stage controller  3  via a cable  31 . 
   By employing the above-described structure and using the following modifications in the processes shown in  FIGS. 7 and 8 , return and eject processes can be carried out with the operating unit  30 . 
   1. In Step  604 , the destination for storing the current position is the RAM  404  or the NVRAM  405  in the stage controller  3 . 
   2. In Steps  605 ,  622 , and  623 , the position coordinates are read out from the RAM  404  or the NVRAM  405  in the stage controller  3 . 
   3. In Step  616 , the dialog display is changed to a dialog displayed on the display unit  505  of the operating unit  30  or a warning sound. 
   4. In Steps  609  and  632 , instead of operating the buttons on the application GUI, buttons or a joystick on the operating unit  30  are operated. 
   The E/R button  504  may be disposed not only on the operating unit  30  but also on the XY stage  8  or inside the examination apparatus main body  1  near the XY stage  8 . 
   According to this embodiment, the speed of the XY stage  8  during the return and eject processes is constant. However, the return and eject movements may be carried out at any speed selected by the user by sending a command from the computer  5  via the RS232 cable  24  and storing information on the selected speed in the NVRAM  405  of the stage controller  3 . 
   According to this embodiment, the return position of the XY stage  8 , i.e., the home position or the position of the XY stage  8  immediately before eject was carried out, is distinguished by double-clicking or single-clicking the E/R button  805 . Instead, however, a home eject button may be added so that when the E/R button  805  is operated, the XY stage  8  returns to the position immediately before ejected and when the home return button is operated, the XY stage  8  returns to the home position. 
   The return process carried out when the E/R button  805  is operated is shown in  FIG. 11 . This process is the same as that shown in  FIG. 8 , except that Steps  621  and  622  are not included. Since the steps included in this process have already been described above, descriptions thereof are not repeated. The process carried out when the home return button is operated is the same as that shown in  FIG. 11 , except that Step  623  is replaced by Step  622  in  FIG. 8 . 
   According to this embodiment, the open or closed state of the access door  7  is detected by the micro switch  201 . Instead, however, the open or closed state of the access door  7  may be detected using a detection unit such as a magnetic sensor or an optical sensor. 
   According to this embodiment, the circular region  314  having the same shape as the outline of the examination field of the objective lens  14  having the lowest magnifying power is marked on the stage plate  301 . By marking the outlines of the examination fields of the other objective lenses  14  concentrically with the circular region  314 , the specimen  11  can be disposed even more easily. 
   According to this embodiment, the communication interfaces between the computer  5  and the system controller  2 , the stage controller  3 , and the illumination device  4  conform to a specific standard. These communication interfaces may conform to well-known communication standards, such as IEEE1394, USB, RS232C, Ethernet, and standards for wireless LAN. 
   In this embodiment, a process may be added so that when a command for terminating the control application of the computer  5  is issued, the current condition of the XY stage  8  is determined. Then, when the XY stage  8  is at the eject position, the return process is automatically started, and after the return process is completed, the control application is terminated. This process is the same as that shown in  FIG. 7 , except that Step  601  is changed to a step in which the termination of the application is instructed, and Steps  603  to  616  are omitted. In  FIG. 8 , Step  621  is changed to “display selected dialog?” The subsequent steps are the same. The application is terminated only when the complete return process is carried out. 
   According to this embodiment, the mechanism for preventing the anesthetic tube  28  from slacking is a wind-up mechanism including the spring  331 . Instead, however, as shown in  FIG. 17 , a wind-up mechanism including a weight  1401  may be employed. Moreover, as shown in  FIGS. 18A to 18C , a mechanism for constantly pulling the anesthetic tube  28  includes a rod  1501  with a known torsion coil spring  1503 . This mechanism has a through-hole  1502  formed in the chassis. 
   An examination apparatus according to a second embodiment of the present invention will be described below with reference to  FIGS. 12A to 16 . 
   The examination apparatus according to this embodiment has the same structure as the examination apparatus according to the first embodiment ( FIG. 1 ), except that a small window for changing the specimen  11  is provided in the access door  7 . The stage plate  301  is projected through this small window to enable a user to change the specimen  11 . 
   In the second embodiment, the components that are the same as those according to the first embodiment are represented by the same reference numerals, and descriptions thereof are not repeated. 
     FIGS. 12A and 12C  illustrate an access door  1201  included in the examination apparatus according to this embodiment and the area around the access door  1201 . Near the center of the access door  1201 , a sliding window  1202  slidable in the horizontal direction is provided. When the sliding window  1202  is slid toward the left in the drawings, a sliding opening  1204  is formed to allow access to the inside of the examination apparatus main body  1 . 
   Near the sliding window  1202 , a photo interrupter  1203  for detecting the open or closed state of the sliding window  1202  is provided. When the sliding window  1202  is slid to the left by a predetermined amount, a light-blocking plate  1205  attached to the sliding window  1202  blocks the light incident on the photo interrupter  1203 . The width of the sliding opening  1204  that enables light incident on the photo interrupter  1203  to be blocked is sufficiently greater than the total width of the stage plate  301  and the fixing unit  310  on the XY stage  8 . 
     FIGS. 12B and 12D  illustrate the stage plate  301  of the XY stage  8  being projected outside from the sliding opening  1204 . The position of the XY stage  8  in the vertical direction is set to a height so that the lower surface of the stage plate  301  does not come into contact with the lower edge of the sliding opening  1204 , for example, 5 mm upward. In this way, even when the specimen  11  disposed on the stage plate  301  is thick, the specimen  11  will not come into contact with an edge of the sliding opening  1204 . 
   Next, the operation of the examination apparatus according to this embodiment will be described with reference to the flow chart in  FIG. 13 . 
   In Step  1301 , when the E/R button  805  is operated, in Step  1302 , it is determined whether the current position of the XY stage  8  is the return position (examination position). Here, when it is determined that the XY stage  8  is at the return position, the eject process is started. When it is determined that the XY stage  8  is not at the return position, the return process is started in Step  1317  (refer to  FIG. 16 ). 
   In Step  1303 , it is determined whether or not the access door  1201  is open on the basis of the on or off state of the micro switch  201  provided near the access door  1201 . When it is determined that the access door  1201  is open, the eject process starts in Step  1304 . Since Steps  1304  to  1315  of the eject process are the same as Steps  604  to  615  shown in  FIG. 7 , descriptions thereof are not repeated. 
   The process returns to Step  1303 . When the access door  1201  is not open, in Step  1318 , it is determined whether or not the sliding window  1202  is open. When it is determined that the sliding window  1202  is not open, in Step  1319 , a dialog indicating that the eject process cannot be carried out because the access door and the sliding window are closed is displayed. Then, the eject process is completed. On the other hand, when it is determined that the sliding window  1202  is open, coordinates (X, Y, Z) for the current position of the XY stage  8  are stored in the storage device (Step  1316 ), and the eject process using the sliding window  1202  is started (Step  1320 ,  FIGS. 14 and 15 ). 
   The eject process using the sliding window  1202  is to move the stage plate  301  of the XY stage  8  in a manner such that the stage plate  301  protrudes out from the opening that is formed by opening the sliding window  1202 . 
   As shown in  FIG. 15 , first, the Z coordinate of the eject position is read out, and it is determined whether or not the current Z coordinate matches the read-out Z coordinate (Steps  1321  and  1322 ). Here, when it is determined that both Z coordinates match, the process proceeds to Step  1335 . 
   On the other hand, when it is determined that the Z coordinates do not match, in Step  1323 , the XY coordinates of an intermediate point are read out. The intermediate point is a point substantially in the middle of a first point corresponding to XY coordinates (Y coordinate in particular) of the stage plate  301  when the stage plate  301  is disposed directly below the objective lens  14 , i.e., when the stage plate  301  is in the optical axis of the objective lens  14 , and a second point corresponding to XY coordinates (Y coordinate in particular) of the stage plate  301  when the stage plate  301  is moved in the Y direction to a position near the access door  1201  but not in contact with the access door  1201 . When the stage plate  313  is at the second point, the stage supporting plate  313  is disposed directly below the objective lens  14  and the stage plate  301  is not disposed orthogonal to the objective lens  14 . 
   In Step  1324 , it is determined whether or not the read-out XY coordinates and the coordinates for the intermediate point match. When it is determined that both coordinates match, the process proceeds to Step  1330 . 
   On the other hand, when it is determined that the coordinates do not match, in Step  1325 , the stage plate  301  of the XY stage  8  starts moving in the XY directions toward the intermediate point. 
   When the XY stage  8  starts moving toward the intermediate point, in Step  1326 , the XY stage  8  is constantly checked to determine whether or not it has reached the intermediate point. In Step  1328 , when a button on the application GUI is operated, in Step  1329 , the XY stage  8  is stopped, and the eject process is aborted (proceed to A in  FIG. 13 ). In Step  1326 , when the XY stage  8  reaches the intermediate point, in Step  1327 , the XY stage  8  is stopped, and the movement of the XY stage  8  to the intermediate point is complete. 
   Next, the eject movement in the Z direction is carried out. In Step  1330 , a command is sent through the system controller  2  to start moving the XY stage  8  in the Z direction. While the XY stage  8  is moving, in Step  1331 , the XY stage  8  is constantly checked to determine whether or not it has reached the eject position. In Step  1333 , when a button on the application GUI is operated, in Step  1334 , the movement of the XY stage  8  in the Z direction is stopped, and the eject process is aborted (proceed to A in  FIG. 13 ). When the XY stage  8  reaches the eject position in Step  1331 , the movement of the XY stage  8  in the Z direction is stopped in Step  1332 , and the eject process in the Z direction is completed. 
   Next, as shown in  FIG. 15 , the eject movement in the XY directions is carried out. In Step  1335 , the XY coordinates of the eject position are read out, and the XY stage  8  is moved (Step  1336 ). 
   While the XY stage  8  is moving, in Step  1337 , the XY stage  8  is constantly checked to determine whether or not it has reached the eject position. In Step  1339 , when a button on the application GUI is operated, in Step  1340 , the movement of the XY stage  8  in the Z direction is stopped, and the eject process is aborted (proceed to A in  FIG. 13 ). When the XY stage  8  reaches the eject position in Step  1337 , the movement of the XY stage  8  in the Z direction is stopped in Step  1338 , and the eject movement in the Z direction is completed. 
   The above-described steps complete the eject process. When the eject process is completed (i.e., the process is completed after carrying out Step  1338 ), the current state of the XY stage  8  (i.e., disposed at the return or eject position) is changed to the “ejected state.” In other words, when the eject process is aborted because of a button being operated in Step  1339 ,  1328 , or  1333 , the current state of the XY stage  8  remains in the “return state,” in which the XY stage  8  is at the position where it was when the eject process was started. 
   The return process will be described with reference to  FIG. 16 . 
   In Step  1351 , it is determined whether or not the access door  1201  is open. When it is determined that the access door  1201  is open, the return process according to the first embodiment shown in  FIG. 8  is carried out. When it is determined that the access door  1201  is not open, the process proceeds to Step  1352 , and it is determined whether or not the E/R button  805  was double-clicked in Step  1301 . When it is determined that the E/R button  805  was double-clicked, the coordinates for a predetermined home position are read out from the storage device of the computer  5  in Step  1353 . However, at this time, the X and Y coordinates of the read-out coordinates are the coordinates for the predetermined home position, and the Z coordinate is the coordinate for the value stored the last time the eject process was carried out. 
   In Step  1352 , when it is determined that the E/R button  805  was not double-clicked (i.e., clicked only once), in Step  1354 , the coordinates (X, Y, Z) for the position of the XY stage  8  stored when a command for carrying out the eject process was received are read out. Since the subsequent steps are the same as the steps in the eject process using the sliding window shown in  FIG. 13  except that “eject” is changed to “return”, detailed descriptions of these steps are not repeated. The return position determination in Step  1355  corresponds to Steps  1322 ; the intermediate point determination in Step  1356  corresponds to Steps  1323  and  1324 ; moving the intermediate point in Step  1357  corresponds to Steps  1325  to  1329 ; moving the return position in Step  1358  corresponds to Steps  1330  to  1334 ; and moving the return position in Step  1359  corresponds to Steps  1336  to  1340 . 
   According to the second embodiment of the present invention, an opening that allows the specimen  11  to be changed is formed in the access door  1201  that is provided to limit access to the inside of the examination apparatus having the same configuration as that according to the first embodiment. Since the stage plate  301  on which the specimen  11  is disposed can be automatically moved in and out through the opening, the specimen  11  can be changed easily, and, moreover, the specimen  11  can be treated easily.