Patent Publication Number: US-2017355949-A1

Title: Observation apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International Application PCT/JP2016/059694, with an international filing date of Mar. 25, 2016, which is hereby incorporated by reference herein in its entirety. This application claims the benefit of Japanese Patent Application No. 2015-072980, filed on Mar. 31, 2015, the content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an observation apparatus. 
     BACKGROUND ART 
     In the related art, there is a known observation apparatus with which the state of cells is observed while culturing the cells in an incubator (for example, see Patent Literature 1). In this observation apparatus, an objective lens that collects light coming from the cells, which are adhered to a bottom surface of a culturing container, is disposed below the culturing container so as to face the bottom surface of the culturing container and so that the optical axis thereof is arranged in the vertical direction, and an image-capturing optical system that includes an image-acquisition device that captures the light coming from the cells and being collected by the objective lens is disposed below the objective lens. 
     CITATION LIST 
     Patent Literature 
     {PTL 1} Japanese Unexamined Patent Application, Publication No. 2005-326495 
     SUMMARY OF INVENTION 
     Technical Problem 
     Because of this, with the observation apparatus of Patent Literature 1, the height thereof needs to be high enough to accommodate the length of the objective lens and the image-capturing optical system that is disposed below the objective lens, including lenses, the image-acquisition device, and so forth. 
     An object of the present invention is to provide an observation apparatus with which it is possible to observe imaging subjects, such as cells or the like, without causing an increase in the apparatus size. 
     Solution to Problem 
     An aspect of the present invention provides an observation apparatus including: a flat-plate-like stage on which a container accommodating a sample is placed and through which light can pass; a deflecting member that is disposed below the stage and that deflects light coming from the sample on the stage into a substantially horizontal direction; an objective lens that collects the light deflected by the deflecting member; and an image-acquisition device that captures the light collected by the objective lens. 
     In the above-described aspect, the objective lens may be provided with one or more movable lenses that can be moved in optical-axis directions thereof, and a focal-point adjusting mechanism that may move the movable lenses in the optical-axis directions is provided. 
     The above-described aspect may be provided with: an image-capturing unit provided with the deflecting member, the objective lens, and the image-acquisition device; and a moving mechanism that moves the image-capturing unit in the direction parallel to the stage. 
     In the above-described aspect, the stage may be formed of an optically transparent material, and a housing in which the stage serves as a top plate, and that accommodates the image-capturing unit and the moving mechanism in an airtight state may be provided. 
     The above-described aspect may be provided with a transmitting portion that transmits an image acquired by the image-acquisition device to the exterior. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a longitudinal sectional view showing a state in which a container is installed in an observation apparatus according to an embodiment of the present invention. 
         FIG. 2  is a plan view showing the internal structure of the observation apparatus in  FIG. 1 . 
         FIG. 3  is a perspective view showing an example of another way of attaching an illumination apparatus to a container installed in the observation apparatus in  FIG. 1 . 
         FIG. 4  is a magnified plan view of an image-capturing unit, showing a modification of the observation apparatus in  FIG. 1 . 
         FIG. 5  is a magnified plan view of an image-capturing unit, showing another modification of the observation apparatus in  FIG. 1 . 
         FIG. 6  is a magnified side view of an image-capturing unit, showing another modification of the observation apparatus in Fig. 
         FIG. 7  is a magnified plan view of an image-capturing unit, showing another modification of the observation apparatus in  FIG. 1 . 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     An observation apparatus  1  according to an embodiment of the present invention will be described below with reference to the drawings. 
     As shown in  FIG. 1 , the observation apparatus  1  according to this embodiment is provided with: a housing  4  in which an optically transparent stage  3  on which a container  2  accommodating a sample P is placed serves as a top plate; an image-capturing unit  6  that is disposed in the housing  4 ; and a moving mechanism  7  that two-dimensionally moves the image-capturing unit  6  in directions parallel to the top plate. 
     The stage  3  is, for example, a flat glass plate, with which it is possible to make the light coming from the sample P placed on the stage  3  pass therethrough and enter into the interior of the housing  4 . The housing  4  has an airtight structure so as to prevent the entry of moisture into the housing  4  from the exterior. 
     The image-capturing unit  6  is provided with: a mirror (deflecting member)  8  that is disposed below the stage  3  and that deflects the light that comes from above the stage  3  and that passes therethrough; an objective lens  9  that collects the light deflected by the mirror  8 ; and an image-acquisition device  10  that captures the light collected by the objective lens  9 . 
     The mirror  8  has a reflecting surface  8   a  that is disposed at substantially 45° with respect to the stage  3  and is configured so as to deflect the light coming from the sample P at substantially 90°, thus directing the light into a substantially horizontal direction. The objective lens  9  is provided with one or more lenses (movable lenses)  11  that are disposed so as to have a substantially horizontal optical axis S so as to collect the light deflected by the mirror  8 . 
     As shown in  FIG. 2 , the image-capturing unit  6  is provided with a focal-point adjusting mechanism  12  that moves the one or more lenses  11  that constitute the objective lens  9  in the directions parallel to the optical axis S. The focal-point adjusting mechanism  12  is, for example, a linear motion mechanism provided with a motor  13  and a ball screw  14 , and is configured so that the ball screw  14  is rotated by actuating the motor  13 , so that a nut  15  engaged with the ball screw  14  is linearly moved along the optical axis S of the objective lens  9 , and so that the lenses  11  secured to the nut  15  can thus be moved along the optical axis S of the objective lens  9 . 
     As shown in  FIG. 2 , the moving mechanism  7  is constituted of two linear motion mechanisms  16  and  17  that are disposed so as to be orthogonal to each other. The first linear motion mechanism  16  is provided with: a guide rail  18  secured to the housing  4 ; a slider  19  that is supported so as to be movable in a first horizontal direction X along the guide rail  18 ; and a driving mechanism  20  that moves the slider  19 . The driving mechanism  20  is provided with a motor  21  and a ball screw  22 . 
     The second linear motion mechanism  17  is provided with: a guide rail  23  secured to the slider  19  of the first linear motion mechanism  16 ; a slider  24  that is supported so as to be movable in a second horizontal direction Y along the guide rail  23 ; and a driving mechanism  25  that moves the slider  24 . The driving mechanism  25  is also provided with a motor  26  and a ball screw  27 . 
     In the interior thereof, the housing  4  is provided with: a transmitting-receiving portion (transmitting portion)  28  that wirelessly transmits image signals acquired by the image-acquisition device  10  to the exterior and that receives instruction signals from the exterior; and a control portion  29  that controls the focal-point adjusting mechanism  12  and the moving mechanism  7  on the basis of the instruction signals received by the transmitting-receiving portion  28 . 
     Examples of the instruction signals include: instruction signals for an operator or a program, which has confirmed the focusing state of an image by using the image signals that have been transmitted to the exterior from the transmitting-receiving portion  28 , to actuate the focal-point adjusting mechanism  12  in one of two directions; and instruction signals for the operator who wishes to check another viewing-field area to move the image-capturing unit  6  in one of the two directions by means of the moving mechanism  7 . 
     The operation of the thus-configured observation apparatus  1  according to this embodiment will be described below. 
     In order to observe cells (sample) P, during culturing, by using the observation apparatus  1  according to this embodiment, the cells are accommodated in the container  2 , such as an optically transparent cell-culturing flask, and the cells are made to adhere to the bottom surface thereof. 
     The bottom surface is made to face downward in this state; the container  2  is placed on the stage  3  of the observation apparatus  1 ; the container  2  and the observation apparatus  1  are accommodated in an incubator; and culturing is started. The illumination light to be radiated onto the sample P may be emitted from a light source in the incubator, or, as shown in  FIG. 1 , the illumination light may be emitted from an illumination apparatus (light source)  30  that is secured to each container  2 . Although the illumination apparatus  30  shown in  FIG. 1  is an example that is secured to the top plate of the container  2 , alternatively, as shown in  FIG. 3 , the illumination apparatus  30  may be secured to a side surface of the container  2 . In  FIG. 3 , the reference sign  31  is a belt that secures the observation apparatus  1 , the container  2 , and the illumination apparatus  30  into a single unit. 
     When the illumination light is radiated onto the sample P in the container  2  from the illumination apparatus  30 , the illumination light is refracted due to the shape or the refractive index of the sample P, or is dimmed due to the transmittance of the sample P, thus passing through the stage  3  in the form of transmitted light carrying information about the sample P, and enters the housing  4 . 
     The light that has entered the housing  4  is deflected at 90° by the mirror  8 , thus being collected by the objective lens  9  that has the optical axis S in the substantially horizontal direction, and is captured by the image-acquisition device  10 . An acquired image is wirelessly transmitted by the transmitting-receiving portion  28  to the exterior, and thus, it is possible to perform observation outside the incubator. 
     The operator or the program checks, by using the image acquired by the image-acquisition device  10 , whether or not the focal point of the objective lens  9  is appropriately aligned with the sample P, and transmits instruction signals for actuating the focal-point adjusting mechanism  12  in one of the two directions in the case in which the focal point and the sample P are not aligned. The transmitted instruction signals are received by the transmitting-receiving portion  28 , thus actuating the focal-point adjusting mechanism  12 . 
     When the ball screw  14  is rotated by the rotation of the motor  13 , the nut  15  is moved in one of the horizontal directions in accordance with the rotating direction of the ball screw  14 , the lenses  11  secured to the nut  15  are made to move in the horizontal direction, and, consequently, the focal position of the objective lens  9  is moved in the top-to-bottom direction. 
     In other words, the focal position is moved upward when the lenses  11  are moved in the direction toward the mirror  8 , and the focal position is moved downward when the lenses  11  are moved in the direction away from the mirror  8 . By doing so, it is possible to acquire a clear image by adjusting the focal position to an appropriate position. 
     When the operator wishes to observe a different position, the operator transmits instruction signals for moving the moving mechanism  7  in one of the two directions. The transmitted instruction signals are received by the transmitting-receiving portion  28 , thus actuating the moving mechanism  7 . The observation position is moved in one horizontal direction Y when the image-capturing unit  6  is moved along the second linear motion mechanism  17 , and the observation position is moved in the other horizontal direction X when the second linear motion mechanism  17  and the image-capturing unit  6  are moved along the first linear motion mechanism  16 . By doing so, it is possible to two-dimensionally adjust the observation position. 
     As has been described above, with the observation apparatus  1  according to this embodiment, because the light that has entered the housing  4  after passing through the stage  3  is deflected by the mirror  8  into the substantially horizontal direction and is collected by the objective lens  9  that has the substantially horizontal optical axis S, there is an advantage in that it is possible to keep the height of a space inside the housing  4  to a size that is about the same as the diameter of the objective lens  9 . 
     In other words, as shown in  FIG. 1 , it is possible to observe the culturing state during culturing by accommodating the observation apparatus  1 , in which the height thereof is kept at the minimum, in the incubator together with the container  2 . 
     With the observation apparatus  1  according to this embodiment, because the focal position of the objective lens  9  is moved in the top-to-bottom direction by moving the one or more lenses  11  that constitute the objective lens  9  in the horizontal directions, it is possible to adjust the focal position without having to ensure a large height for the space inside the housing  4 . Accordingly, there is an advantage in that it is possible to reduce the thickness of the observation apparatus  1 . 
     With the observation apparatus  1  according to this embodiment, because the image-capturing unit  6  is two-dimensionally moved in the horizontal directions X and Y by means of the moving mechanism  7 , even though the viewing-field area that can be captured at once may be small, it is possible to observe the state of the sample P over a greater area by capturing images thereof while moving the image-capturing unit  6  in the horizontal directions X and Y. In this case also, because the employed structure is such that a large observation area is ensured by moving the small image-capturing unit  6  in the horizontal directions X and Y, large optical components are not necessary, and thus, there is an advantage in that it is possible to reduce the thickness of the apparatus. 
     In this embodiment, although the observation apparatus  1  provided with the focal-point adjusting mechanism  12 , the moving mechanism  7 , the transmitting-receiving portion  28  and the control portion  29  has been described, the present invention is not limited thereto. 
     Specifically, in the case in which an objective lens  9  having a large depth of field is used, or in the case in which the focal-position adjustment is not necessary, the focal-point adjusting mechanism  12  may be omitted. 
     In the case in which the sample P is placed in a relatively small region, or in the case in which it suffices to observe a specific area in a portion of the sample P, it is not necessary to provide the moving mechanism  7 . In the case in which the moving mechanism  7  and the focal-point adjusting mechanism  12  are not remotely operated from the exterior, the receiving function of the transmitting-receiving portion  28  is not necessary. In addition, in the case in which the moving mechanism  7  and the focal-point adjusting mechanism  12  are not provided, the receiving function of the transmitting-receiving portion  28  and the control portion  29  are not necessary. 
     In the case in which a storing portion (not shown) that stores images acquired by the image-acquisition device  10  is provided in the housing  4 , it is not necessary to transmit the acquired image signals to the exterior, and thus, the transmitting-receiving portion  28  may be omitted. 
     In the description of this embodiment, although the sample P is irradiated with the illumination light coming from the light source in the incubator or the illumination apparatus  30  secured to the container  2 , alternatively, as shown in  FIG. 4 , light sources  32  that emit illumination light upward from below the stage  3  may be provided in the area surrounding the mirror  8 . 
     For example, it is preferable that a plurality of LED light sources that can independently be turned on be employed as the light sources  32 . Because the illumination light emitted upward from the area surrounding the mirror  8  is reflected by an inner surface of the top plate of the container  2 , the illumination light passes through the sample P from diagonally thereabove, and is made incident on the mirror  8  below the stage  3 , it is possible to form a shadow in an image of the sample P, as in the case of oblique illumination. Therefore, it is possible to enhance the visibility of the sample P, such as transparent cells. 
     In this case, as shown in  FIG. 5 , a plurality of light sources  32  may be disposed with spaces therebetween in radial directions centered on the mirror  8 , and the light sources  32  to be turned on may be changed. By doing so, it is possible to change the entry angle of the illumination light that passes through the sample P, and thus, it is possible to enhance the visibility by changing the shadow that is formed in an image of the sample P. 
     In this embodiment, as shown in  FIG. 6 , a prism  33  that deflects the light that has passed through the objective lens  9  at 90° again may be provided. By doing so, it is possible to substantially horizontally arrange the image-acquisition device  10  and a substrate to which the image-acquisition device  10  is secured, and thus, there is an advantage in that it is not necessary to increase the height of the space inside the housing  4  even if an image-acquisition device  10  having a large image-acquisition surface is employed. Besides the mirror  8 , a deflection prism  34  having a reflecting surface may be employed as the deflecting member. As shown in  FIG. 7 , by additionally folding the optical path, it is possible to arrange optical components from the mirror  8  to the image-acquisition device  10  in a more compact manner. 
     In the description of this embodiment, although a cell-culturing flask has been described as an example of the container  2 , alternatively, a petri dish, a microplate, a cell-culturing bag, or the like may be employed. 
     In this embodiment, although a mechanism with which the focal position is adjusted by moving the lenses  11  in the direction parallel to the optical axis S with respect to the image-acquisition device  10  has been described as an example of the focal-point adjusting mechanism  12 , alternatively, the focal position may be adjusted by moving the image-acquisition device  10  in the direction parallel to the optical axis S with respect to the lenses  11 . The image-acquisition device  10  and the lenses  11  may be moved in the direction parallel to the optical axis S as a single unit. By doing so, because the focal position is adjusted in a state in which a predetermined spacing is kept between the image-acquisition device  10  and the lenses  11 , it is possible to configure the apparatus so that the magnifications of images to be acquired are not changed even if the focal position is adjusted. 
     In this embodiment, although an optically transparent flat glass plate has been described as an example of the stage  3 , alternatively, a flat-plate-like light-blocking member that blocks the illumination light may be employed. 
     In this case, the light-blocking member is provided with an opening at a portion thereof in a circumferential direction or at a portion thereof in a radial direction, and is configured so that the light coming from the sample P travels into the interior of the housing  4  by passing through the opening. The opening is formed in a size that is smaller than the bottom surface of the container  2 . By doing so, it is possible to make the interior of the housing  4  airtight by placing the container  2  on the stage  3  so that the bottom surface of the container  2  covers the opening. 
     In the case in which the container  2  is not placed on the stage  3 , because the space inside the housing  4  and the exterior are connected by the opening, access to the optical systems, such as the objective lens  9  or the like, in the housing  4  is facilitated via the opening. By doing so, it is possible to easily exchange the optical systems, such as the objective lens  9  or the like, with lenses of different magnifications. 
     In addition, the opening may be provided in the optically transparent flat glass plate. 
     According the above described the embodiment of the observation apparatus, by placing the container accommodating the sample on the stage and by irradiating the sample with the illumination light, the light that has passed through or that has been reflected by the sample passes through the stage downward, thus being deflected by the deflecting member. Because the objective lens in which the optical axis thereof is arranged in a substantially horizontal direction is placed in the deflection direction, the light coming from the sample that has been deflected is collected by the objective lens and is captured by the image-acquisition device. 
     In this case, by arranging the optical axis of the objective lens in the substantially horizontal direction, with regard to the space below the stage, it suffices to have a height that corresponds to the diameter of the objective lens. In other words, by placing the objective lens so that the optical axis thereof points in the substantially horizontal direction, it is also possible to place the image-acquisition device, which captures the light collected by the objective lens, on the extension of the optical axis of the objective lens. Therefore, it is possible to reduce the thickness by reducing the height-direction size. With a thin observation apparatus, it is possible to accommodate the observation apparatus in an incubator together with the container installed on the stage, and thus, it is possible to observe the state of cells while culturing the cells. 
     The objective lens may be provided with one or more movable lenses that can be moved in optical-axis directions thereof, and a focal-point adjusting mechanism that may move the movable lenses in the optical-axis directions is provided. 
     By doing so, when the focal-point adjusting mechanism is actuated, the one or more movable lenses that constitute the objective lens are moved in the optical-axis direction, which changes the distance between the objective lens and the deflecting member, and thus, it is possible to move the focal position of the objective lens, which is disposed above the stage, in top-to-bottom directions. Specifically, with a conventional observation apparatus in which the optical axis of the objective lens is arranged in the vertical direction, the focal position is adjusted by moving objective lens in the top-to-bottom directions, and this configuration requires a greater height, whereas, with this aspect, it is possible to adjust the focal position without increasing the height. 
     The observation apparatus may be provided with: an image-capturing unit provided with the deflecting member, the objective lens, and the image-acquisition device; and a moving mechanism that moves the image-capturing unit in the direction parallel to the stage. 
     By doing so, it is possible to ensure a large observation area by moving the image-capturing unit in the horizontal directions by actuating the moving mechanism even if the viewing-field area of the image-capturing unit itself is small. In this case also, it is possible to employ a moving mechanism having a form that extends in the horizontal directions, and thus, it is possible to achieve a thickness reduction without increasing the height. 
     The stage may be formed of an optically transparent material, and a housing in which the stage serves as a top plate, and that accommodates the image-capturing unit and the moving mechanism in an airtight state may be provided. 
     By doing so, even if the observation apparatus is accommodated in an incubator together with the container, the interior of which has high humidity, over a long period of time, the housing in the airtight state prevents moisture from coming into contact with the image-capturing unit and the moving mechanism, and thus, it is possible to keep these devices in sound states. 
     The observation apparatus may be provided with a transmitting portion that transmits an image acquired by the image-acquisition device to the exterior. 
     By doing so, it is possible to observe the state of the sample over a long period of time by using images that are transmitted from the transmitting portion in a state in which the container is placed on the stage without having to touch the container. For example, because images acquired by the image-acquisition device are transmitted outside the incubator by the transmitting portion when culturing is started after accommodating the container in the incubator in the state in which the container is placed on the stage, it is possible to observe, over a long period of time from the exterior, the state of the sample during culturing without having to take the container out of the incubator. 
     REFERENCE SIGNS LIST 
     
         
           1  observation apparatus 
           2  container 
           3  stage 
           4  housing 
           6  image-capturing unit 
           7  moving mechanism 
           8  mirror (deflecting member) 
           9  objective lens 
           10  image-acquisition device 
           11  lens (movable lens) 
           12  focal-point adjusting mechanism 
           28  transmitting-receiving portion (transmitting portion) 
         P sample