Patent Publication Number: US-2022221702-A1

Title: Microscope used in multiple microscopies

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2021-002410, filed Jan. 8, 2021, the entire contents of which are incorporated herein by this reference. 
     TECHNICAL FIELD 
     The disclosure of the present specification is related to a microscope used in multiple microscopies. 
     BACKGROUND 
     At present with advancement of late marriage and late birth, the number of patients who receive fertility treatment has been increased year by year, and demands for an assisted reproductive technology (ART) have been further increased. 
     ART is a collective term of technologies for combining an egg and sperm taken out from people with each other in vitro such as micro insemination using intracytoplasmic sperm injection (ICSI), and in vitro fertilization (IVF). ART is distinguished from general artificial insemination for injecting collected sperm into a womb to be combined with an egg in vivo. 
     A technology associated with ART is described, for example, in International Publication No. WO 2012/150689. International Publication No. WO 2012/150689 describes a microscope suitable for intracytoplasmic sperm injection (ICSI) used in the micro insemination which is a type of ART. It is noted that ICSI is a method of piercing an injection pipette containing sperm into an egg held by a holding pipette to directly inject the sperm into the egg. 
     SUMMARY 
     A microscope according to an aspect of the present invention is a microscope used in multiple microscopies, the microscope including an objective used in common in the multiple microscopies, and a magnification adjustment device arranged on an image side of the objective and configured to adjust an optical magnification of the microscope in response to switching of the multiple microscopies. 
     A microscope according to another aspect of the present invention is a microscope used in multiple microscopies, the microscope including an objective used in common in the multiple microscopies, and a magnification adjustment device that includes a plurality of optical units corresponding to the multiple microscopies and is arranged on an image side of the objective, the magnification adjustment device being configured to adjust an optical magnification of the microscope in response to switching of the multiple microscopies, when the optical magnification of the microscope is different from a predetermined magnification for a microscopy after the switching, change the optical magnification of the microscope to the predetermined magnification, and perform the switching of the multiple microscopies and the adjustment of the optical magnification of the microscope by switching the plurality of optical units. Each of the plurality of optical units includes at least one of an optical system having a magnification according to a magnification ratio between a magnification of the objective and a predetermined magnification for the microscopy corresponding to the optical unit, and a modulation optical element according to the microscopy corresponding to the optical unit, and a casing accommodating together at least one of the optical system and the modulation optical element which are included in the optical unit. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram exemplifying a configuration of a microscopic system  1 . 
         FIG. 2  is a diagram exemplifying a configuration of a microscope  10 . 
         FIG. 3  is a diagram exemplifying a configuration of an operation unit of an input device  3 . 
         FIG. 4  is a diagram exemplifying a relationship among a predetermined magnification for each of microscopies, a magnification of an objective, and a magnification of a magnification adjustment device. 
         FIG. 5  is a flowchart illustrating an example of a procedure of micro insemination. 
         FIG. 6  is a diagram exemplifying a configuration of a microscope  100 . 
         FIG. 7  is a diagram exemplifying a configuration of a microscope  200 . 
         FIG. 8  is a diagram exemplifying a configuration of a microscope  300 . 
         FIG. 9  is a diagram exemplifying a configuration of a microscope  400 . 
         FIG. 10  is a diagram exemplifying a configuration of a microscope  500 . 
         FIG. 11  is a diagram exemplifying a configuration of a universal condenser  600 . 
         FIG. 12  is a diagram exemplifying a configuration of a magnification adjustment device  700 . 
         FIG. 13  is a diagram exemplifying a configuration of a microscopic system  1   a.    
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In micro insemination, sperm is selected by an embryologist under a microscope, and sperm suitable for fertilization is injected into an egg. To increase a success rate of the micro insemination, a series of works performed under the microscope is to be skillfully performed in a short period of time by switching microscopies and observation magnifications for various settings. When a microscope described in International Publication No. WO 2012/150689 is used, since the embryologist can change the microscopy and the observation magnification at once by a button operation, microscopic operations are simplified, and as a result, work hours can be shortened. 
     However, in the microscope described in International Publication No. WO 2012/150689, when the observation magnification is changed together with the microscopy, objectives are switched in response to the button operation. For this reason, deviation from accurate focus may occur due to a slight difference of a parfocal distance between the objectives before and after the switching. In addition, the center of the field of view may be deviated due to axial misalignment. When such phenomena occur, since the embryologist takes time to correct these deviations, it is difficult to continue the observation smoothly after the switching of the microscopies. 
     In view of the above described circumstances, hereinafter, embodiments of the present invention will be described. 
     First Embodiment 
       FIG. 1  is a diagram exemplifying a configuration of a microscopic system  1 .  FIG. 2  is a diagram exemplifying a configuration of a microscope  10 .  FIG. 3  is a diagram exemplifying a configuration of an operation unit of an input device  3 .  FIG. 4  is a diagram exemplifying a relationship among a predetermined magnification for each of the microscopies, a magnification of an objective, and a magnification (intermediate variable magnification) of a magnification adjustment device. 
     The microscopic system  1  illustrated in  FIG. 1  is a microscopic system used in the micro insemination or the like, and includes the microscope  10  to be used in multiple microscopies. A user of the microscopic system  1  is not particularly limited, but is, for example, an embryologist. Specimens set as observation objects by the microscopic system  1  are, for example, reproductive cells such as sperm and an egg accommodated in a Petri dish which are phase objects. 
     The microscope  10  includes at least an objective  40  used in common in the multiple microscopies, and a magnification adjustment device  70  that is an example of a magnification adjustment unit configured to adjust an optical magnification of the microscope  10  in response to switching of the multiple microscopies. As illustrated in  FIG. 1 , the magnification adjustment device  70  is a device different from a revolver  45  configured to switch the objective  40 , and is arranged on an image side of the objective  40 . It is noted that in the present specification, “to adjust” means that an object to be adjusted is changed when necessary and is not changed when unnecessary. 
     Herein, the microscopy refers to an observation method using the microscope, and is also referred to as a microscopic method. Representative microscopies include a bright field (BF) microscopy, a dark field (DF) microscopy, a polarized light (PO) microscopy, a phase contrast (PC) microscopy, a differential interference contrast (DIC) microscopy, a fluorescence (FL) microscopy, a relief contrast (RC) microscopy, and the like. It is noted that the relief contrast (RC) microscopy is also referred to as a modulation contrast (MC) microscopy. 
     In addition, the optical magnification of the microscope  10  refers to a magnification of an optical image of a specimen which is formed by the microscope  10 , and indicates the number of times the optical image to be formed is as large as the specimen. The optical magnification of the microscope  10  may be, for example, an observation magnification (total magnification) in an eyepiece barrel  80  provided in the microscope  10 , or may be a magnification on an imaging surface of an imaging device  90  provided in the microscope  10 . It is noted that an observation magnification (total magnification) on a monitor of a computer  4  included in the microscopic system  1  is obtained by multiplying the magnification on the imaging surface by the monitor magnification. Therefore, in the microscopic system  1 , when the magnification adjustment device  70  adjusts the optical magnification of the microscope  10 , the observation magnification is also adjusted at the same time. 
     In the micro insemination, as will be described below, an observation object or an observation purpose is different for each of the microscopies to be used. For this reason, in general, when the embryologist switches the microscopies, the observation magnifications are also to be switched. It is noted that the observation magnification used for each of the microscopies is restricted by the observation object and the observation purpose in the microscopy, and is accordingly broadly fixed. Therefore, the optical magnification of the microscope  10  corresponding to the observation magnification is also broadly fixed. Under such a situation, when the microscope  10  according to the present embodiment is used, the magnification adjustment device  70  can appropriately adjust the optical magnification of the microscope  10  in response to the switching of the multiple microscopies. Specifically, for example, when the optical magnification of the microscope  10  is different from a predetermined magnification for the microscopy after the switching, the magnification adjustment device  70  may set the optical magnification of the microscope  10  to be close to the predetermined magnification, or more preferably, may change the optical magnification of the microscope  10  to the predetermined magnification. When the predetermined magnification for each of the microscopies is appropriately set, since the embryologist does not need to switch the observation magnifications by a separate operation from the switching operation of the microscopies, the microscopic operations in the micro insemination can be simplified. 
     Furthermore, in the microscope  10 , the objective  40  is used in common in the multiple microscopies, and the adjustment of the optical magnification of the microscope  10  is performed by the magnification adjustment device  70  on the image side relative to the objective  40 . That is, at the time of the switching of the microscopies, the switching of the objective  40  does not occur. Thus, since the deviation from the accurate focus, shift of the center of the field of view, or the like due to the switching of the objective  40  does not occur, the amount of adjustment work to be performed after the switching of the microscopies and the observation magnifications can be suppressed. 
     In this manner, in the microscope  10 , the work necessary for the switching itself of the microscopies and the observation magnifications can be simplified, and also the adjustment work after the switching can be simplified. Therefore, in accordance with the microscope  10 , the microscopies and the observation magnifications can be promptly switched, and also the observation of the specimen can be promptly started in the microscopy after the switching. 
     Hereinafter, with reference to  FIG. 1  to  FIG. 4 , a specific example of the configuration of the microscopic system  1  will be described in detail. As illustrated in  FIG. 1 , the microscopic system  1  includes the microscope  10 , a microscope controller  2  configured to control the microscope  10 , and the input device  3  configured to switch the microscopies. As illustrated in  FIG. 1 , the microscopic system  1  may further include the computer  4  configured to receive an image obtained by the microscope  10 . 
     The microscope controller  2  is a control device configured to control the microscope  10  according to operations performed by the embryologist using the input device  3  and the computer  4 . The microscope controller  2  may perform, for example, rotation control of a turret of a universal condenser  29  included in the microscope  10  and a turret of the magnification adjustment device  70 , or may perform light emission control of a light source device  21 . The microscope controller  2  may output an image obtained by the microscope  10  to the computer  4 , or may output the image to a monitor provided instead of the computer  4 . 
     The input device  3  is a hand switch device configured to change settings related to the microscopies and the observation magnifications. As illustrated in  FIG. 3 , the input device  3  has five buttons (a button B 1  to a button B 5 ) respectively corresponding to the multiple microscopies, for example. In the microscopic system  1 , when the button of the input device  3  is pressed, the turret of the universal condenser  29  and the turret of the magnification adjustment device  70  rotate, and the settings related to the microscopies and the observation magnifications are switched according to the pressed button. For this reason, when the embryologist simply presses any of these buttons, the settings related to the microscopies and the observation magnifications can be promptly switched. 
     The computer  4  includes at least a processor and a memory. The computer  4  may be a general use device such as a personal computer, or may be a computer dedicated to the microscopic system  1 . As illustrated in  FIG. 1 , the computer  4  may include a monitor, and may display the image obtained by the microscope  10  on the monitor. 
     It is noted that a configuration may be adopted where the microscopic system  1  does not include the computer  4 . The computer  4  is not necessarily needed, and the image obtained by the microscope  10  may be displayed on the monitor connected to the microscope controller  2 . In addition, a configuration may be adopted where the microscopic system  1  does not include the monitor, and the embryologist may perform eye observation of the specimen via the eyepiece barrel  80  described below which is included in the microscope  10 , and operate the input device  3 . In addition, the computer  4  may have a function of the input device  3 , and when the input device  3  described above is operated, an instruction input to the microscope controller  2  may be input from the computer  4  to the microscope controller  2 . 
     As illustrated in  FIG. 1 , the microscopic system  1  may include a manipulator including a pair of pipettes (a pipette  7  and a pipette  8 ) to be operated by left and right handles (a handle  5  and a handle  6 ). The manipulator is used to assist the work of the micro insemination by the embryologist. 
     The microscope  10  is an inverted microscope including a transmitted illumination system  20  above a stage  30 . A plurality of objectives  40  forming the optical image of the specimen by a combination with a tube lens  60  are attached to the revolver  45 . Furthermore, the microscope  10  includes the eyepiece barrel  80  and the imaging device  90 , and can support the eye observation and digital imaging of the specimen. 
     As will be described below, the microscope  10  includes a modulation optical element configured to visualize an unstained phase object which is removably inserted into each of an illumination optical path and an observation optical path. When the modulation optical element according to the microscopy is inserted into and removed from the optical path, the embryologist can observe the phase object by the microscope  10  while switching the multiple microscopies. 
     It is noted that the microscope  10  can support five microscopies including the bright field microscopy, the relief contrast microscopy, the differential interference contrast microscopy, the phase contrast microscopy, and the polarized light microscopy. It is noted however that the microscopies that can be supported by the microscope  10  are not limited to the above described examples, and may include other microscopies such as the fluorescence microscopy and the dark field microscopy. In addition, to be used in the micro insemination, the microscope  10  desirably supports at least the bright field microscopy, the relief contrast microscopy, and the differential interference contrast microscopy or the phase contrast microscopy, and furthermore, the microscope  10  more desirably supports the polarized light microscopy. In the micro insemination, the bright field microscopy is used when positioning of the specimen and positioning of the pipettes are performed by using an objective with a low magnification such as 4× or 10×. In addition, the relief contrast microscopy is used when form observation of the egg and motility check of the sperm (specifically, whether or not the sperm swims fast and straight) are performed by using an objective with a magnification such as 20× or 40×. The differential interference contrast microscopy is used when the observation of the sperm is performed to see whether or not a head part of the sperm has a defect by using an objective with a high magnification such as 60×. The polarized light microscopy is used when a spindle having polarization property which appears in a mature egg is observed by using an objective with a magnification such as 20× or 40×. 
     The transmitted illumination system  20  illuminates the specimen placed on the stage  30  with light from above the stage  30 . As illustrated in  FIG. 1  and  FIG. 2 , the transmitted illumination system  20  includes the light source device  21  and the universal condenser  29 . Furthermore, as illustrated in  FIG. 2 , the transmitted illumination system  20  includes a polarizer  22  and a compensator  23  between the light source device  21  configured to emit illumination light and the universal condenser  29 . 
     The light source device  21  may include, for example, a light emitting diode (LED) light source, or may include a halogen lamp. The polarizer  22  is a modulation optical element configured to take out linear polarized light having a particular oscillation direction, and is mainly used in the relief contrast microscopy, the differential interference contrast microscopy, and the polarized light microscopy in the microscope  10 . In the bright field microscopy (and the phase contrast microscopy), the polarizer  22  may be removed from the optical path. It is noted that the polarizer  22  is rotatably arranged in the microscope  10  such that an oscillation direction that the polarizer  22  itself has is changed relative to an oscillation direction that an analyzer  61  described below (see  FIG. 2 ) or a polarization plate  25   a  described below (see  FIG. 2 ) has. 
     The compensator  23  is a modulation optical element used for measuring retardation due to birefringence of the specimen. The compensator  23  is, for example, a Senarmont compensator, a liquid crystal modulation element, or a Broce-Kohler compensator. In the microscope  10 , the compensator  23  is used in the polarized light microscopy for adjusting a contrast of the image by changing the retardation caused in the compensator  23 . In the bright field microscopy, the relief contrast microscopy, and the differential interference contrast microscopy (and the phase contrast microscopy), the compensator  23  may be removed from the optical path. 
     As illustrated in  FIG. 2 , the universal condenser  29  includes a plurality of modulation optical elements accommodated in the turret and a condenser lens  28 . The plurality of modulation optical elements include a modulator  25  for the relief contrast microscopy, a differential interference contrast (DIC) prism  26 , and a ring slit plate  27 . The plurality of these modulation optical elements and an apertured plate  24  are used by being switched by the rotation of the turret according to the microscopy. 
     It is noted that the apertured plate  24  is a so-called hollow hole of the turret, and represents a slot of the turret where the modulation optical element is not arranged. The apertured plate  24  is used in the bright field microscopy and the polarized light microscopy. The modulator  25  is obtained by combining a rectangular slit plate  25   b  in which a rectangular slit is formed with the polarization plate  25   a  arranged to cover a part of the slit. The modulator  25  is used in the relief contrast microscopy. The DIC prism  26  is used in the differential interference contrast microscopy. The ring slit plate  27  in which a ring shaped slit is formed is used in the phase contrast microscopy. It is noted that the modulator  25 , the DIC prism  26 , and the ring slit plate  27  are inserted into and removed from a pupil surface (entrance pupil, front focal position) of the condenser lens  28 , for example, by the rotation of the turret. 
     As illustrated in  FIG. 2 , a plurality of the objectives  40  (an objective  41 , an objective  42 , and an objective  43 ) are provided below the stage  30  to be switchable by the revolver  45 . The objectives  40  form the optical image of the specimen by a combination with the tube lens  60 . Furthermore, a relay lens  62  and the analyzer  61  are provided on the optical path on the image side of the tube lens  60 . 
     It is noted that the analyzer  61  is the modulation optical element configured to take out linear polarized light having a particular oscillation direction similarly as in the polarizer  22 , and is mainly used in the differential interference contrast microscopy and the polarized light microscopy in the microscope  10 . In the bright field microscopy and the relief contrast microscopy (and the phase contrast microscopy), the analyzer  61  may be removed from the optical path, or an orientation of the polarizer  22  or the analyzer  61  may be adjusted such that the polarizer  22  and the analyzer  61  have a parallel Nicol relationship. It is noted that similarly as in the polarizer  22 , the analyzer  61  may be rotatably arranged in the microscope  10  to change the oscillation direction that the analyzer  61  itself has relative to the oscillation direction that the polarizer  22  has. In addition, the analyzer  61  may be provided in an optical unit included in the magnification adjustment device  70  which will be described below. For example, the analyzer  61  may be provided in an optical unit  71  which is an optical unit corresponding to the polarized light microscopy and an optical unit  74  which is an optical unit corresponding to the differential interference contrast microscopy. 
     At least one of the plurality of objectives  40  is used in common in the multiple microscopies. The objective used in common in the multiple microscopies is not particularly limited. Hereinafter, a case will be described as an example in which an objective with the magnification of 20× (for example, the objective  41 ) is used in common in the multiple microscopies, but a plurality of objectives used in common may be attached to the revolver  45 . It is noted that in this example, the objective  41  is an objective at 20× with a numerical aperture of 0.7, but instead of the objective  41 , for example, the objective  42  that is an objective at 10× with the numerical aperture of 0.7 may be used in common in the multiple microscopies. The numerical aperture of 0.7 is a numerical aperture having a sufficient resolution even when a form of the sperm (for example, an internal section of the head part of the sperm) is observed at the observation magnification that is higher than or equal to 60×. 
     As illustrated in  FIG. 2 , the magnification adjustment device  70  includes a plurality of optical units (the optical unit  71 , an optical unit  72 , an optical unit  73 , the optical unit  74 , and an optical unit  75 ) corresponding to the multiple microscopies, and the turret that is a switching device configured to switch the plurality of optical units. 
     The optical unit  71  is an optical unit corresponding to the polarized light microscopy, and is inserted onto the optical path when the specimen is observed in the polarized light (PO) microscopy. An optical system  71   a  configured to adjust the optical magnification of the microscope  10  is included in the optical unit  71 . A magnification of the optical system  71   a  is previously determined such that the optical magnification of the microscope  10  is set as a predetermined magnification frequently used in the polarized light microscopy in the micro insemination. Specifically, since the polarized light microscopy is used for checking the spindle of the egg as will be described below, the predetermined magnification for the polarized light microscopy is, for example, 20× which is suitable to an observation of a structure of the egg as illustrated in  FIG. 4 . Therefore, when the objective  40  at 20× is used in common in the multiple microscopies, the magnification of the optical system  71   a  is 1×. It is noted that the optical unit  71  may further include an analyzer, and in this case, the analyzer  61  between the magnification adjustment device  70  and a mirror  63  may be omitted. When the analyzer is included in the optical unit  71  and the analyzer  61  is omitted, the brighter observation than before can be performed in the microscopies in which the analyzer is not needed (the bright field microscopy, the relied contrast microscopy, and the phase contrast microscopy). 
     The optical unit  72  is an optical unit corresponding to the bright field microscopy, and is inserted onto the optical path when the specimen is observed in the bright field (BF) microscopy. An optical system  72   a  configured to adjust the optical magnification of the microscope  10  is included in the optical unit  72 . A magnification of the optical system  72   a  is previously determined such that the optical magnification of the microscope  10  is set as a predetermined magnification frequently used in the bright field microscopy in the micro insemination. Specifically, the bright field microscopy is used for search of a drop in a Petri dish, alignment of the pipette, and the like. For this reason, the predetermined magnification for the bright field microscopy is a relatively low magnification to secure a wide field of view, and is, for example, 10× as illustrated in  FIG. 4 . Therefore, when the objective  40  at  20 X is used in common in the multiple microscopies, the magnification of the optical system  72   a  is at 0.5×, and is below 1×. 
     The optical unit  73  is an optical unit corresponding to the relief contrast microscopy, and is inserted onto the optical path when the specimen is observed in the relief contrast (RC) microscopy. An optical system  73   a  configured to adjust the optical magnification of the microscope  10  and a modulator  73   b  for the relief contrast microscopy are included in the optical unit  73 . A magnification of the optical system  73   a  is previously determined such that the optical magnification of the microscope  10  is set as a predetermined magnification frequently used in the relief contrast microscopy in the micro insemination. Specifically, the relief contrast microscopy is used for checking an entire shape of the sperm, the motility of the sperm, and furthermore, a first polar body of the egg as will be described below. For this reason, the predetermined magnification for the relief contrast microscopy is, for example, 20× suitable for the observation of the structure of the egg and the movement of the sperm as illustrated in  FIG. 4 . Therefore, when the objective  40  at 20× is used in common in the multiple microscopies, the magnification of the optical system  73   a  is 1×. The modulator  73   b  includes three areas having different types of transmittance (for example, an area with the transmittance of approximately 100%, an area with the transmittance of approximately 5%, and an area with the transmittance of approximately 0%). The modulator  73   b  is a modulation optical element paired with the modulator  25  accommodated in the universal condenser  29 , and is used in the relief contrast microscopy together with the modulator  25 . 
     The optical unit  74  is an optical unit corresponding to the differential interference contrast microscopy, and is inserted onto the optical path when the specimen is observed in the differential interference contrast (DIC) microscopy. An optical system  74   a  configured to adjust the optical magnification of the microscope  10  and a DIC prism  74   b  are included in the optical unit  74 . A magnification of the optical system  74   a  is previously determined such that the optical magnification of the microscope  10  is set as a predetermined magnification frequently used in the differential interference contrast microscopy in the micro insemination. Specifically, the differential interference contrast microscopy is used for observing a vacuole in the sperm as will be described below. For this reason, the predetermined magnification for the differential interference contrast microscopy is a relatively high magnification, and is, for example, 60× suitable for the observation of the sperm structure as illustrated in  FIG. 4 . Therefore, when the objective  40  at 20× is used in common in the multiple microscopies, the magnification of the optical system  74   a  is 3×, and is a magnification above 1×. The DIC prism  74   b  is a modulation optical element paired with the DIC prism  26  accommodated in the universal condenser  29 , and is used in the differential interference contrast microscopy together with the DIC prism  26 . It is noted that the optical unit  74  may further include an analyzer, and in this case, the analyzer  61  between the magnification adjustment device  70  and the mirror  63  may be omitted. When the analyzer is included in the optical unit  74  and the analyzer  61  is omitted, the brighter observation than before can be performed in the microscopies in which the analyzer is not needed (the bright field microscopy, the relied contrast microscopy, and the phase contrast microscopy). 
     The optical unit  75  is an optical unit corresponding to the phase contrast microscopy, and is inserted onto the optical path when the specimen is observed in the phase contrast (PC) microscopy. An optical system  75   a  configured to adjust the optical magnification of the microscope  10  and a phase plate  75   b  are included in the optical unit  75 . A magnification of the optical system  75   a  is previously determined such that the optical magnification of the microscope  10  is set as a predetermined magnification frequently used in the phase contrast microscopy in the micro insemination. Specifically, the phase contrast microscopy is used to observe the vacuole in the sperm similarly as in the differential interference contrast microscopy. For this reason, the predetermined magnification for the phase contrast microscopy is a relatively high magnification, and is, for example, 60× suitable for the observation of the sperm structure as illustrated in  FIG. 4 . Therefore, when the objective  40  at 20× is used in common in the multiple microscopies, the magnification of the optical system  75   a  is 3×, and is a magnification above 1×. The phase plate  75   b  is a modulation optical element paired with the ring slit plate  27  accommodated in the universal condenser  29 , and is used together with the ring slit plate  27  in the phase contrast microscopy. 
     As described above, each of the plurality of optical units includes at least one of the optical system and the modulation optical element according to the microscopy corresponding to the optical unit. In addition, the optical system included in the optical unit has a magnification according to a magnification ratio (the predetermined magnification/the magnification of the objective) between the magnification of the objective  40  and the predetermined magnification for the microscopy corresponding to the optical unit. 
     In this example, the optical unit  71  and the optical unit  72  include only the optical system. That is, only the optical system is accommodated in each of the casings of the optical unit  71  and the optical unit  72 . In addition, the optical unit  73 , the optical unit  74 , and the optical unit  75  include both the optical system and the modulation optical element. That is, both the optical system and the modulation optical element are accommodated in each of the casings of the optical unit  73 , the optical unit  74 , and the optical unit  75 . It is noted however that the plurality of optical units may include optical units including only the modulation optical element, and each of the plurality of optical units may include a casing that accommodates together at least one of the optical system and the modulation optical element. 
     The magnification adjustment device  70  is arranged between the tube lens  60  arranged on the image side of the objective  40  and the eyepiece barrel  80  (and the imaging device  90 ). Specifically, the magnification adjustment device  70  is arranged between the relay lens  62  and the mirror  63  such that a pupil modulation element (the modulator  73   b , the DIC prism  74   b , the phase plate  75   b , or the like) included in the optical unit can be arranged on a plane optically conjugated to a pupil surface (exit pupil, rear focal position) of the objective  40 . It is noted that the mirror  63  is a mirror arranged to be removably inserted into the optical path, and is used for switching between eye observation and digital imaging. To be still more specific, the magnification adjustment device  70  is arranged between the relay lens  62  and the analyzer  61  such that the DIC prism  74   b  included in the optical unit  74  is inserted onto the optical path between the polarizer  22  arranged on the illumination optical path and the analyzer  61  arranged on the observation optical path. With the aforementioned arrangement, the magnification adjustment device  70  adjusts the optical magnification of the microscope  10  on the optical path on the image side relative to the tube lens  60 . 
     The magnification adjustment device  70  having the above described configuration switches the optical unit to be arranged on the optical path according to the microscopy by the switching device. Thus, the magnification adjustment device  70  can adjust the optical magnification of the microscope  10  on the optical path on the image side relative to the tube lens  60  and also perform the switching of the multiple microscopies. That is, the magnification adjustment device  70  can perform the switching of the multiple microscopies and the adjustment of the optical magnification of the microscope  10  at once by switching the plurality of optical units. 
     It is noted that the magnifications described above with regard to the optical systems included in the plurality of optical units are merely examples. It is sufficient when the magnification is appropriate to an observation object and a purpose in each of the microscopies. For example, it is sufficient when the predetermined magnification for the bright field microscopy (first predetermined magnification) is lower than the predetermined magnification for the differential interference contrast microscopy or the phase contrast microscopy (second predetermined magnification). Therefore, it is sufficient when the magnification of the optical system  72   a  is lower than the magnification of the optical system  74   a  or the optical system  75   a . In addition, for example, it is sufficient when the predetermined magnification for the relief contrast microscopy (third predetermined magnification) is higher than the predetermined magnification for the bright field microscopy (first predetermined magnification) and lower than the predetermined magnification for the differential interference contrast microscopy or the phase contrast microscopy (second predetermined magnification). Therefore, it is sufficient when the magnification of the optical system  73   a  is higher than the magnification of the optical system  72   a  and lower than the magnification of the optical system  74   a  or the optical system  75   a . In addition, for example, it is sufficient when the predetermined magnification for the polarized light microscopy (fourth predetermined magnification) is higher than the predetermined magnification for the bright field microscopy (first predetermined magnification) and lower than the predetermined magnification for the differential interference contrast microscopy or the phase contrast microscopy (second predetermined magnification). More specifically, the predetermined magnification for the polarized light microscopy (fourth predetermined magnification) may be equal to the predetermined magnification for the relief contrast microscopy (third predetermined magnification). Therefore, it is sufficient when the magnification of the optical system  71   a  is higher than the magnification of the optical system  72   a  and lower than the magnification of the optical system  74   a  or the optical system  75   a , and may be equal to the magnification of the optical system  73   a.    
     In addition, the example has been illustrated in which the magnification adjustment device  70  adjusts the optical magnification of the microscope  10  from 10× to 60×, but such an adjustment range of the optical magnification is also merely an example. The magnification ratio of an upper limit value to a lower limit value of the optical magnification may be below the aforementioned 6 to 1. It is noted however that it is sufficient that the optical magnification is adjusted such that various observation objects in the micro insemination can be appropriately observed. To do so, the magnification adjustment device  70  desirably adjusts the optical magnification in an adjustment range in which the magnification ratio of the upper limit value to the lower limit value of the optical magnification is 3 or higher to 1. 
     In addition, as described above, the magnification adjustment device  70  desirably adjusts the optical magnification of the microscope  10  from a magnification lower than the optical magnification of the objective  40  (in this example, 10×) to a magnification higher than the optical magnification of the objective  40  (in this example, 60×). Specifically, in response to switching to a predetermined microscopy, the magnification adjustment device  70  desirably adjusts the optical magnification of the microscope  10  to a magnification at which it is possible to observe a range wider than a range on a specimen surface set by the magnification of the objective  40  and an objective field number (OFN) of the objective (for example, Φ1.1 mm when the OFN of the objective at 20× is 22). More specifically, for example, in response to the switching to the bright field microscopy, the magnification adjustment device  70  desirably sets an intermediate variable magnification of 1× or below. Thus, while the objective having a sufficient resolution is used in common in the multiple microscopies, the wide field of view can be secured. 
     The eyepiece barrel  80  and the imaging device  90  are arranged in a stage after the mirror  63  for switching between the eye observation and the digital imaging. When the mirror  63  is inserted into the optical path, the light is guided to the eyepiece barrel  80 , and when the mirror  63  is removed from the optical path, the light is guided to the imaging device  90 . The eyepiece barrel  80  includes an eyepiece lens  81 . In addition, the imaging device  90  includes an adapter lens  91  and an imaging element  92 . The imaging element  92  is, for example, a charge coupled device (CCD) image sensor, a complementary metal-oxide-semiconductor (CMOS) image sensor, or the like. 
     The description has been provided above while the case is supposed where magnifications of the eyepiece lens  81  and the adapter lens  91  are both 1×, but the magnifications of the eyepiece lens  81  and the adapter lens  91  are not particularly limited. Since the magnification of the eyepiece lens  81  (the adapter lens  91 ) affects the optical magnification of the microscope  10 , the magnification adjustment device  70  may adjust the optical magnification by taking into account the magnification of the eyepiece lens  81  (the adapter lens  91 ). 
     Furthermore, as illustrated in  FIG. 2 , the microscope  10  may include a laser assisted hatching unit  50 . The laser assisted hatching unit  50  irradiates the specimen with laser light by introducing the laser light to the optical path from a position between the objective  40  and the tube lens  60 . More specifically, the laser assisted hatching unit  50  is used to irradiate zona pellucida surrounding an embryo with the laser light to reduce a thickness of a part of the zona pellucida or cut out the zona pellucida such that, for example, the embryo grown from the fertilized egg can be implanted. The laser assisted hatching unit  50  includes a splitter  51 , a scanner  52 , a lens  53 , and laser  54 . The splitter  51  is, for example, a dichroic mirror. The scanner  52  is, for example, a galvanometer scanner, and is configured to adjust an irradiation position of the laser light in a direction orthogonal to an optical axis of the objective  40 . The lens  53  converts the laser light into parallel luminous flux. 
       FIG. 5  is a flowchart illustrating an example of a procedure of the micro insemination. Hereinafter, with reference to  FIG. 5 , the procedure of the micro insemination performed by the embryologist using the microscopic system  1  described above and the operation of the microscopic system  1  in the micro insemination will be specifically described. 
     First, the embryologist prepares a specimen (step S 1 ). At this point, the embryologist creates, for example, the specimen including a plurality of drops in a Petri dish, and arranges the Petri dish on the stage  30 . The plurality of drops include a washing drop for washing a pipette, a sperm suspension drop including sperm, an egg operation drop including an egg, and the like. These drops are coated with mineral oil, for example. 
     Next, the embryologist sets up the microscopic system  1  (step S 2 ). At this point, the embryologist presses the button B 1  of the input device  3 , for example, and changes the settings of the microscopies and the observation magnifications of the microscopic system  1 . The microscope controller  2  that has detected the press of the button B 1  controls the microscope  10  to switch the microscopy to the bright field microscopy and switch the optical magnification of the microscope  10  to 10×. More specifically, the microscope  10  rotates the turret of the universal condenser  29  such that the apertured plate  24  is located on the optical path, and furthermore, rotates the turret of the magnification adjustment device  70  such that the optical unit  72  is located on the optical path. Thereafter, the embryologist adjusts positions of the pipette  7  and the pipette  8  by operating the handle  5  and the handle  6  to bring the pipette  7  and the pipette  8  into focus. Furthermore, the stage  30  is moved, and the pipette  7  and the pipette  8  are washed by the washing drop. It is noted that during the observation in the bright field microscopy, the polarizer  22  or the analyzer  61  is adjusted such that the polarizer  22  and the analyzer  61  have a parallel Nicol relationship. It is noted however that when the analyzer  61  between the magnification adjustment device  70  and the mirror  63  is omitted and each of the optical unit  71  and the optical unit  74  includes the analyzer, it is not necessary to perform such an adjustment that the polarizer and the analyzer have a parallel Nicol relationship. 
     When the setup is completed, the embryologist selects sperm (from step S 3  to step S 6 ). First, the embryologist selects satisfactory sperm based on a form and motility (step S 3 ). At this point, the embryologist presses the button B 2  of the input device  3 , for example, and changes the settings of the microscopies and the observation magnifications of the microscopic system  1 . The microscope controller  2  that has detected the press of the button B 2  controls the microscope  10  to switch the microscopy to the relief contrast microscopy and switch the optical magnification of the microscope  10  to 20×. More specifically, the microscope  10  rotates the turret of the universal condenser  29  such that the modulator  25  is located on the optical path, and furthermore, rotates the turret of the magnification adjustment device  70  such that the optical unit  73  is located on the optical path. Thereafter, the embryologist moves the stage  30  to move the observation position to the sperm suspension drop, and bring the sperm in the sperm suspension drop into focus, so that the satisfactory sperm suitable for the fertilization is selected. At this point, a quality of the sperm is determined based on the form and the motility of the sperm shaded by the relief contrast microscopy, and the satisfactory sperm is selected based on the determination. At this point, the polarizer  22  is desirably rotated to adjust the contrast. 
     When the satisfactory sperm is selected based on the form and the motility, the embryologist immobilizes the selected satisfactory sperm (step S 4 ). At this point, the embryologist rubs a tail part of the satisfactory sperm against a bottom surface of the Petri dish with the pipette, and damages the tail part of the satisfactory sperm for the immobilization. It is noted that this work is performed in the relief contrast microscopy at 20× similarly as in step S 3 . 
     Thereafter, the embryologist further selects the satisfactory sperm based on an internal structure of the immobilized satisfactory sperm (step S 5 ). At this point, the embryologist presses the button B 4  of the input device  3 , for example, and changes the settings of the microscopies and the observation magnifications of the microscopic system  1 . The microscope controller  2  that has detected the press of the button B 4  controls the microscope  10  to switch the microscopy to the differential interference contrast microscopy and switch the optical magnification of the microscope  10  to 60×. More specifically, the microscope  10  rotates the turret of the universal condenser  29  such that the DIC prism  26  is located on the optical path, and furthermore, rotates the turret of the magnification adjustment device  70  such that the optical unit  74  is located on the optical path. Thereafter, the embryologist observes a head part of the immobilized satisfactory sperm in detail, and selects the satisfactory sperm suitable for the fertilization. At this point, the quality of the sperm is determined based on a size of the vacuole existing in the head part which is visualized by the differential interference contrast microscopy, and the satisfactory sperm is selected based on the determination. Specifically, the satisfactory sperm having a small vacuole is selected. It is noted that during the observation in the differential interference contrast microscopy, the polarizer  22  or the analyzer  61  is adjusted such that the polarizer  22  and the analyzer  61  have a cross Nicol relationship. 
     It is noted that in step S 5 , the phase contrast microscopy may be used instead of the differential interference contrast microscopy. In this case, the embryologist may press, for example, the button B 5  of the input device  3 , and change the settings of the microscopies and the observation magnifications of the microscopic system  1 . The microscope controller  2  that has detected the press of the button B 5  controls the microscope  10  to switch the microscopy to the phase contrast microscopy and switch the optical magnification of the microscope  10  to 60×. More specifically, the microscope  10  rotates the turret of the universal condenser  29  such that the ring slit plate  27  is located on the optical path, and furthermore, rotates the turret of the magnification adjustment device  70  such that the optical unit  75  is located on the optical path. During the observation in the phase contrast microscopy, the polarizer  22  or the analyzer  61  is adjusted such that the polarizer  22  and the analyzer  61  have a parallel Nicol relationship. 
     Thereafter, the embryologist takes the satisfactory sperm selected in step S 5  into injection pipette (the pipette  7 ) (step S 6 ). Thus, the sperm selection work is completed. 
     When the selection of the satisfactory sperm is completed, the embryologist checks the egg for preparation of sperm injection (step S 7  to step S 8 ). First, the embryologist checks a position of the first polar body of the egg (step S 7 ). At this point, the embryologist presses the button B 2  of the input device  3 , for example, and changes the settings of the microscopies and the observation magnifications of the microscopic system  1 . The microscope controller  2  that has detected the press of the button B 2  controls the microscope  10  to switch the microscopy to the relief contrast microscopy and switch the optical magnification of the microscope  10  to 20×. More specifically, the microscope  10  rotates the turret of the universal condenser  29  such that the modulator  25  is located on the optical path, and furthermore, rotates the turret of the magnification adjustment device  70  such that the optical unit  73  is located on the optical path. Thereafter, the embryologist moves the stage  30  to move the observation position to the egg operation drop and bring the egg in the egg operation drop into focus. Furthermore, the position of the first polar body of the egg is checked, and a holding pipette (the pipette  8 ) is operated to change an orientation of the egg such that the first polar body is located in a 12 o&#39;clock direction or a 6 o&#39;clock direction on the clock face. This is because the spindle checked in step S 8  exists in the vicinity of the first polar body with a relatively high probability. In step S 7  too, the polarizer  22  is desirably rotated to adjust the contrast. 
     Thereafter, the embryologist checks the spindle of the egg (step S 8 ). At this point, the embryologist presses the button B 3  of the input device  3 , for example, and changes the settings of the microscopies and the observation magnifications of the microscopic system  1 . The microscope controller  2  that has detected the press of the button B 3  controls the microscope  10  to switch the microscopy to the polarized light microscopy, and also maintains the optical magnification of the microscope  10  at 20× as it is. More specifically, the microscope  10  rotates the turret of the universal condenser  29  such that the apertured plate  24  is located on the optical path, and furthermore, rotates the turret of the magnification adjustment device  70  such that the optical unit  71  is located on the optical path. Thus, in the microscope  10 , the microscopy is switched, but the optical magnification is maintained without change. Thereafter, the embryologist checks the location of the spindle of the egg and operates the holding pipette (the pipette  8 ) to change the orientation of the egg such that the spindle is located in the 12 o&#39;clock or 6 o&#39;clock direction. This is because, in step S 9  which will be described below, a damage to the spindle is avoided by the injection pipette spearing the egg from a 3 o&#39;clock or 9 o&#39;clock direction. In step S 8 , the polarizer  22  or the analyzer  61  is desirably adjusted such that the polarizer  22  and the analyzer  61  have a cross Nicol relationship. 
     Finally, the embryologist injects the sperm into the egg (step S 9 ). At this point, the embryologist presses the button B 2  of the input device  3 , for example, and changes the settings of the microscopies and the observation magnifications of the microscopic system  1 . The microscope controller  2  that has detected the press of the button B 2  controls the microscope  10  to switch the microscopy to the relief contrast microscopy, and also maintains the optical magnification of the microscope  10  at 20× as it is. More specifically, the microscope  10  rotates the turret of the universal condenser  29  such that the modulator  25  is located on the optical path, and furthermore, rotates the turret of the magnification adjustment device  70  such that the optical unit  73  is located on the optical path. Thus, in the microscope  10 , the microscopy is switched, but the optical magnification is maintained without change. Thereafter, the embryologist holds the egg by sucking by the holding pipette (the pipette  8 ), and pierces the injection pipette (the pipette  7 ) into the egg from the 3 o&#39;clock or 9 o&#39;clock direction. Finally, the satisfactory sperm is injected into the inside of the egg from the injection pipette (the pipette  7 ), and the series of procedures is ended. It is noted that in step S 9  too, the polarizer  22  is desirably rotated to adjust the contrast. When the series of procedures illustrated in  FIG. 5  is ended, the embryologist returns the egg to which the sperm has been injected to an incubator for culture. 
     As described above, in accordance with the microscope  10  and the microscopic system  1 , it is possible to adjust the observation magnification at the same time and also appropriately by simply performing the switching operation of the microscopies at the time of the switching of the microscopies which frequently occurs in the micro insemination. For this reason, switching to a desired combination of the microscopy and the observation magnification can be performed in a short period of time. In addition, since the adjustment of the observation magnification is performed without the switching of the objective, deviation of the focus or the center of the field of view hardly occurs. For this reason, an advantage that subsequent work can be promptly started after the switching also contributes to shortening of the work hours of the micro insemination. Therefore, in accordance with the microscope  10  and the microscopic system  1 , the damage to the reproductive cells can be suppressed to the minimum, and the success rate of the micro insemination can be improved. 
     Second Embodiment 
       FIG. 6  is a diagram exemplifying a configuration of a microscope  100 . A microscopic system according to the present embodiment is different from the microscopic system  1  in that the microscope  100  illustrated in  FIG. 6  is included instead of the microscope  10 . The rest is similar to the microscopic system  1 . 
     A main difference between the microscope  100  and the microscope  10  is in that the arrangement of the analyzer and the magnification adjustment device is different, that the configuration for the phase contrast microscopy is not included, and that an objective  44  used in common in the multiple microscopies includes a modulator  44   a  for the relief contrast microscopy. With regard to the arrangement of the analyzer and the magnification adjustment device, more specifically, the microscope  100  is different from the microscope  10  in that the analyzer used in the polarized light microscopy and the differential interference contrast microscopy is arranged in the magnification adjustment device and that the magnification adjustment device is arranged between an objective  40   a  and the tube lens  60 . Hereinafter, the microscope  100  will be described by paying attention to these differences. 
     As long as the pupil modulation element can be arranged in an exit pupil position of the objective  40   a , similarly as in the microscope  10  and the microscopic system  1 , the microscope  100  and the microscopic system including the microscope  100  can also adjust the observation magnification at the same time and also appropriately by simply performing the switching operation of the microscopies at the time of the switching of the microscopies which frequently occurs in the micro insemination. Therefore, the work hours of the micro insemination can be shortened. It is noted that according to this embodiment, the modulator  44   a  for the RC microscopy that is a pupil modulation element is arranged in a pupil position of the objective  44 . 
     A magnification adjustment device  170  included in the microscope  100  is similar to the magnification adjustment device  70  in that a plurality of optical units corresponding to the multiple microscopies are included. An optical unit  171 , an optical unit  172 , an optical unit  173 , and an optical unit  174  are optical units respectively corresponding to the polarized light microscopy, the bright field microscopy, the relief contrast microscopy, and the differential interference contrast microscopy. 
     The optical unit  171  includes an analyzer  171   b . The optical unit  172  includes an optical system  172   a  having a magnification of 0.5×. The optical unit  173  is an empty unit that does not include an optical element and an optical system. The modulator  44   a  for the relief contrast microscopy is not arranged in the optical unit  173  but is arranged in the objective  44 . The optical unit  174  includes an optical system  174   a  having a magnification of 3×, a DIC prism  174   b , and an analyzer  174   c.    
     In this manner, the plurality of optical units included in the magnification adjustment device  170  are similar to the plurality of optical units included in the magnification adjustment device  70  except for the optical unit  173  in that at least one of the optical system having the magnification according to the magnification ratio between the magnification of the objective  40   a  and the predetermined magnification for the microscopy corresponding to the optical unit and the modulation optical element according to the microscopy corresponding to the optical unit is included. 
     Third Embodiment 
       FIG. 7  is a diagram exemplifying a configuration of a microscope  200 . A microscopic system according to the present embodiment is different from the microscopic system  1  in that the microscope  200  illustrated in  FIG. 7  is included instead of the microscope  10 . The rest is similar to the microscopic system  1 . 
     First, the microscope  200  is different from the microscope  10  in that a microscopy switching device  270  configured to switch the multiple microscopies is separately included in addition to a magnification adjustment device  280 , that the configuration for the phase contrast microscopy is not included, and the objective  44  used in common in the multiple microscopies includes the modulator  44   a  for the relief contrast microscopy. It is noted that the microscope  200  is similar to the microscope  100  according to the second embodiment in that the configuration for the phase contrast microscopy is not included and that the objective  44  used in common in the multiple microscopies includes the modulator  44   a  for the relief contrast microscopy. The microscopy switching device  270  includes one or more modulation optical elements (an analyzer  271  and a modulator  273 ) each of which is used in at least one of the multiple microscopies and a turret configured to switch these. The microscopy switching device  270  switches the multiple microscopies by inserting and removing at least one of the one or more modulation optical elements into and from the optical path. 
     Specifically, at the time of switching to the polarized light microscopy, the microscopy switching device  270  may insert the analyzer  271  into the optical path and remove the other modulation optical element from the optical path. In addition, at the time of the switching to the bright field microscopy or the relief contrast microscopy, the microscopy switching device  270  may remove the modulation optical element on the optical path from the optical path. In addition, at the time of switching to the differential interference contrast microscopy, the microscopy switching device  270  may insert the modulator  273  obtained by combining a DIC prism  273   a  with an analyzer  273   b  into the optical path and remove the other modulation optical element from the optical path. 
     Furthermore, the microscope  200  is different from the microscope  10  in that the magnification adjustment device  280  includes a variable magnification optical system. The variable magnification optical system included in the magnification adjustment device  280  has a structure configured to change its own magnification. For example, as illustrated in  FIG. 7 , the variable magnification optical system may include a zoom lens for changing the magnification by moving the lens that is a part of the variable magnification optical system in an optical axis direction. In addition, the variable magnification optical system may include, for example, a variable focal point lens for changing a focal distance by changing a lens shape. 
     When the optical magnification of the microscope  200  is different from the predetermined magnification for the microscopy after the switching by the microscopy switching device  270 , the magnification adjustment device  280  changes the magnification of the microscope  200  by changing the magnification of the magnification adjustment device  280 . Specifically, the microscope  200  may include an interlocking mechanism configured to mechanically interlock the microscopy switching device  270  with the magnification adjustment device  280 , and a handle of the magnification adjustment device  280  may be rotated to a predetermined position in response to rotation of the microscopy switching device  270 . 
     In addition, in the microscopic system including the microscope  200 , when the microscope controller  2  controls the microscopy switching device  270  and the magnification adjustment device  280 , the microscopy switching device  270  may be interlocked with the magnification adjustment device  280  as a result. That is, the microscope controller  2  may control the microscopy switching device  270  and the magnification adjustment device  280  such that the switching of the multiple microscopies by the microscopy switching device  270  and the adjustment of the optical magnification by the magnification adjustment device  280  are interlocked with each other. 
     As long as the pupil modulation element can be arranged in the exit pupil position of the objective  40   a , similarly as in the microscope  10  and the microscopic system  1 , the microscope  200  and the microscopic system including the microscope  200  can also adjust the observation magnification at the same time and also appropriately by simply performing the switching operation of the microscopies at the time of the switching of the microscopies which frequently occurs in the micro insemination. Therefore, the work hours of the micro insemination can be shortened. It is noted that according to this embodiment, the modulator  44   a  for the RC microscopy which is a pupil modulation element is arranged in the pupil position of the objective  44 . 
     Fourth Embodiment 
       FIG. 8  is a diagram exemplifying a configuration of a microscope  300 . A microscopic system according to the present embodiment is different from the microscopic system according to the third embodiment in that the microscope  300  illustrated in  FIG. 8  is included instead of the microscope  200 . The rest is similar to the microscopic system according to the third embodiment. 
     The microscope  300  is similar to the microscope  200  illustrated in  FIG. 7  in that a microscopy switching device and a magnification adjustment device are included. It is noted however that the microscope  300  is different from the microscope  200  in that the microscopy switching device  270  and a magnification adjustment device  380  are arranged on the optical path on the image side relative to the tube lens  60 . In addition, similarly as in the microscope  10  according to the first embodiment, the microscope  300  is also different from the microscope  200  in that the configuration for the phase contrast microscopy is included and that the objective  41  used in the multiple microscopies does not include the modulator for the relief contrast microscopy. It is noted that the magnification adjustment device  380  includes a variable magnification optical system having a structure configured to change its own magnification. 
     The microscope  300  and the microscopic system including the microscope  300  can also adjust the observation magnification at the same time and also appropriately by simply performing the switching operation of the microscopies at the time of the switching of the microscopies which frequently occurs in the micro insemination. Therefore, the work hours of the micro insemination can be shortened. 
     Fifth Embodiment 
       FIG. 9  is a diagram exemplifying a configuration of a microscope  400 . A microscopic system according to the present embodiment is different from the microscopic system according to the fourth embodiment in that the microscope  400  illustrated in  FIG. 9  is included instead of the microscope  300 . The rest is similar to the microscopic system according to the fourth embodiment. 
     The microscope  400  is similar to the microscope  300  illustrated in  FIG. 8  in that a microscopy switching device and a magnification adjustment device are included on the optical path on the image side relative to the tube lens  60 . It is noted however that the microscope  400  is different from the microscope  300  in that a magnification adjustment device  480  includes one or more optical systems (an optical system  481 , an optical system  482 , and an optical system  483 ) each of which is used in at least one of the multiple microscopies instead of the variable magnification optical system, and adjusts an optical magnification of the microscope  400  by inserting and removing at least one of this one or more optical systems into and from the optical path. 
     The microscope  400  and the microscopic system including the microscope  400  can also adjust the observation magnification at the same time and also appropriately by simply performing the switching operation of the microscopies at the time of the switching of the microscopies which frequently occurs in the micro insemination. Therefore, the work hours of the micro insemination can be shortened. 
     Sixth Embodiment 
       FIG. 10  is a diagram exemplifying a configuration of a microscope  500 . A microscopic system according to the present embodiment is different from the microscopic system according to the fifth embodiment in that the microscope  500  illustrated in  FIG. 10  is included instead of the microscope  400 . The rest is similar to the microscopic system according to the fifth embodiment. 
     The microscope  500  is similar to the microscope  400  illustrated in  FIG. 9  in that a microscopy switching device and a magnification adjustment device are included. It is noted however that the microscope  500  is different from the microscope  400  in that the microscopy switching device  270  and a magnification adjustment device  580  are included on the optical path between the objective  40  and the tube lens  60 . It is noted that the microscope  500  is similar to the microscope  400  in that the magnification adjustment device  580  includes one or more optical systems (an optical system  581 , an optical system  582 , and an optical system  583 ) each of which is used in at least one of the multiple microscopies, and adjusts an optical magnification of the microscope  500  by inserting and removing at least one of this one or more optical systems into and from the optical path. 
     As long as a pupil modulation element (a modulator  272 , the DIC prism  273   a , and a phase plate  274 ) can be arranged in the exit pupil position of the objective  40 , the microscope  500  and the microscopic system including the microscope  500  can also adjust the observation magnification at the same time and also appropriately by simply performing the switching operation of the microscopies at the time of the switching of the microscopies which frequently occurs in the micro insemination. Therefore, the work hours of the micro insemination can be shortened. 
     The above described embodiments illustrate the specific examples to facilitate understanding of the invention, and the present invention is not limited to these embodiments. Modified modes obtained by modifying the above described embodiments and substitution modes substituting the above described embodiments may be included. In other words, according to the respective embodiments, components can be modified in a range without departing its gist and scope. In addition, a new embodiment can be implemented by appropriately combining a plurality of components disclosed according to one or more embodiments. In addition, some components may be deleted from the components illustrated in the respective embodiments, or some components may be added to the components illustrated in the embodiments. Furthermore, processing procedures illustrated in the respective embodiments may be performed by swapping an order as long as no contradiction occurs. That is, various modification and alterations can be made with regard to the microscope of the present invention within a range without departing from descriptions of the claims. 
       FIG. 11  is a diagram exemplifying a configuration of a universal condenser  600 . According to the above described embodiments, the example has been illustrated in which the polarizer  22  and the compensator  23  to be arranged on the illumination optical path are arranged outside the turret of the universal condenser  29 . However, as illustrated in  FIG. 11 , the polarizer  22  and the compensator  23  may be included in the universal condenser  600 , and may be inserted into and removed from the optical path when necessary by a turret provided on an incident side of a condenser lens  601  similarly as in the other modulation optical element. 
     It is noted that  FIG. 11  illustrates a configuration in which an optical unit  610  used in the polarized light microscopy, an optical unit  620  used in the bright field microscopy, an optical unit  630  used in the relief contrast microscopy, an optical unit  640  used in the differential interference contrast microscopy, and an optical unit  650  used in the phase contrast microscopy can be switched by the turret of the universal condenser  600 . 
     The optical unit  610  accommodates an apertured plate  613  together with a polarizer  611  and a compensator  612 . The optical unit  620  accommodates an apertured plate  621 . The optical unit  630  accommodates a polarizer  631  and a modulator  632 . The modulator  632  is configured by a polarization plate  632   a  and a rectangular slit plate  632   b . It is noted that the polarizer  631  is accommodated in the optical unit  630  to be rotatable for changing an oscillation direction that the polarizer  631  has relative to an oscillation direction that the polarization plate  632   a  has. The optical unit  640  accommodates a polarizer  641  and a DIC prism  642 . The optical unit  650  accommodates a ring slit plate  651 . 
       FIG. 12  is a diagram exemplifying a configuration of a magnification adjustment device  700 .  FIG. 1  illustrates the example in which the analyzer  61  to be arranged on the observation optical path is arranged outside the turret of the magnification adjustment device. However, as illustrated in  FIG. 12 , the analyzer  61  may be included in the magnification adjustment device, and may be inserted into and removed from the optical path when necessary by the turret of the magnification adjustment device similarly as in the other modulation optical element. 
     It is noted that  FIG. 12  illustrates a configuration in which an optical unit  710  used in the polarized light microscopy, an optical unit  720  used in the bright field microscopy, an optical unit  730  used in the relief contrast microscopy, an optical unit  740  used in the differential interference contrast microscopy, and an optical unit  750  used in the phase contrast microscopy can be switched by the turret of the magnification adjustment device  700 . 
     The optical unit  710  accommodates an analyzer  711  together with an optical system  712 . The optical unit  720  accommodates an optical system  721 . The optical unit  730  accommodates a modulator  731  and an optical system  732 . The optical unit  740  accommodates an analyzer  741 , a DIC prism  742 , and an optical system  743 . The optical unit  750  accommodates a phase plate  751  and an optical system  752 . 
       FIG. 13  is a diagram exemplifying a configuration of a microscopic system  1   a . The microscopic system  1   a  is different from the microscopic system  1  illustrated in  FIG. 1  in that a microscope  800  is included instead of the microscope  10 . The microscope  800  is an erect microscope including the universal condenser  600  illustrated in  FIG. 11  described above and the magnification adjustment device  700  illustrated in  FIG. 12  described above which are respectively on the illumination optical path and the observation optical path. The microscope  800  extracts near infrared light from illumination light emitted from a light source device  801  by a bandpass filter  802  for irradiation of the specimen by the universal condenser  600  with incidence via a collector lens  804 . The embryologist may check an image of the specimen which is captured by an imaging device  808  by the monitor of the computer  4 . In the microscope  800 , the microscopies and the observation magnifications can be changed by switching the magnification adjustment device  700  and the universal condenser  600  in an interlocking manner. 
     According to the above described embodiments, the inverted microscope is exemplified, but as illustrated in  FIG. 13 , the present invention may be applied to an elect microscope, and in this case too, a similar advantage can be attained. In addition, according to the above described embodiments, the example has been illustrated in which the optical elements and the optical systems are switched by using the turret, but the optical elements and the optical systems may be switched by using another switching unit such as a slider. In addition, according to the above described embodiments, the example has been illustrated in which the microscopies and the observation magnifications are switched in an interlocking manner, but furthermore, by being interlocked with these, an amount of the illumination light emitted from the light source device may be adjusted. Specifically, the microscope controller  2  functioning as a light source control device may adjust the amount of the illumination light emitted from the light source device  21  in response to the switching of the multiple microscopies. For example, the microscope controller  2  may control to increase the light amount since the image tends to be darkened in the polarized light microscopy or the differential interference contrast microscopy in which the adjustment is performed such that the polarizer  22  and the analyzer  61  have a cross Nicol relationship.