Patent Publication Number: US-2005135918-A1

Title: Cover glass transfer device for sample sealing apparatus

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a cover glass transfer device for a sample sealing apparatus for affixing a cover glass to a glass slide so as to seal a sample on a glass slide, which comprises an automated process of affixing a cover glass stacked in layers to a glass slide.  
      2. Description of the Related Art  
      In histological testing, or the like, for the purpose of microscopic observation of a cell sample piece, a sample sealing operation is carried out comprising the steps of: placing the cell sample piece on a glass slide, which is a piece of glass; dropping on to the cell sample piece a solution, which is an adhesive agent, for sample sealing; further placing a cover glass made of a thin glass plate thereon to sandwich the cell sample piece between the glass slide and the cover glass; and sealing the cell sample piece.  
      Such an operation for sample sealing has been mechanized. Thus, a cover glass transfer device has been suggested, which picks up and transfers a cover glass from a case onto a glass slide so as to seal a cell sample piece between the glass slide and the cover glass.  
       FIG. 7  shows a process for picking up a cover glass by a cover glass transfer device.  
      In  FIG. 7 , the reference numeral  201  denotes a cover glass housing case in which the opening edge, labeled R, is curved in a convex manner with respect to the inside of the case. The reference numeral  202  denotes cover glasses stacked in layers in the case  201  at an inclined angle θ 3  each having one end thereof, in the longitudinal direction of the cover glass, raised.  
      The reference numeral  203  denotes a cover glass holding rod (to be hereafter referred to as a holding rod) which has a hollow structure inside thereof for holding a cover glass by suction. It is movable in a vertical direction and is supported by an elevating member (not shown). The upper end part of the holding rod  203  is led to a vacuum pump (not shown). The vacuum pump is switched, for example, to connect to the holding rod  203 , or to the atmosphere, via an electromagnetic switching valve (not shown). This electromagnetic switching valve normally connects the holding rod  203  with the vacuum pump, and is controlled by a switching device (not shown) to switch to the atmosphere after the cover glass  202  has been affixed onto a glass slide.  
      On the lower end part of the holding rod  203 , a suction pad  206  is fixed, which comprises an attaching face with an inclined angle θ 3  identical to that of the cover glasses  202  stacked in layers.  
      The reference numeral  204  denotes a cover glass separating metal tool provided above the opening edge part of the case  201 . The reference numeral  205  denotes a cover glass separating pawl, provided above the opening edge part of the case  201  on the opposite side to that of the cover glass separating metal tool  204 . The cover glass separating metal tool  204  is fixed at a position higher than that of the cover glass separating pawl  205 . As shown in  FIG. 7  both the ends of the cover glass  202   a , held by the holding rod  203  at the inclined angle θ 3 , engage the cover glass separating metal tool  204  and the cover glass separating pawl  205  at almost the same time.  
      As the elevating member descends, driven by an elevating drive mechanism (not shown), the holding rod  203  descends toward the top cover glass  202   a  of the layered stack in the case  201 . Thereafter, the suction pad  206  stops descending when coming into contact with the top cover glass  202   a , and holds the cover glass  202   a  by suction. After the cover glass  202   a  has been held by suction, the elevating member allows the holding rod  203  to ascend. At this time, an adjacent lower cover glass  202   b  in the stack may also be picked up—being attached to the lower face of the cover glass  202   a.    
      As the holding rod  203  continues to ascend further, both longitudinally oriented ends of the held top cover glass  202   a  engage the separating metal tool  204  and the separating pawl  205  provided above both the opening edge parts of the cover glass housing case  201 . Since the holding rod  203  continues to move upward, the cover glass  202   a  begins to adopt an upwardly convex deflection.  
      When the deflection has become sufficiently large, adjacent cover glass  202   b  attached to the lower face of the cover glass  202   a  cannot follow the thus made deflection. Then, space is formed between the cover glasses, and the adjacent cover glass  202   b  falls naturally due to its own weight. This allows the independent transfer of a single cover glass  202   a  by the holding rod  203 .  
      When the cover glass  202   b  falls, due to its own weight, the falling cover glass  202   b  is guided into case  201  by the curved opening edge R of the housing case  201 , allowing the cover glass  202   b  to slip smoothly into the housing case  201 . After having passed beyond the cover glass separating pawl  205 , the still attached cover glass  202   a  returns to its flat state at the inclined angle θ 3 , and then proceeds to the process shown in  FIG. 8  where it is affixed onto a glass slide placed on a glass slide placing base.  
      In  FIG. 8 , the reference numeral  207  denotes a glass slide placed on a glass slide placing base (not shown). A cell sample piece  208  is affixed onto the glass slide  207 , and a sealing adhesive solution  209  is dropped onto second end portion of the glass slide  207  (the right side of the glass slide  207  in  FIG. 8 ).  
      The holding rod  203  is positioned above the first end portion which is the other end portion with respect to the second end portion of the glass slide  207  on which the sealing adhesive solution  209  has been dropped. The cover glass  202   a  on the first end side is sucked by the suction pad  206  at the inclined angle θ 3 . Therefore, at the beginning of the affixation process, the cover glass  202   a  is held hanging from the suction pad  206  fixed on the holding rod  203  so as to be brought downward at the inclined angle θ 3 . Then, the cover glass  202   a  proceeds in the affixation process initially having the inclined angle θ 3 . At this time, an elevating member (not shown) brings the holding rod  203  down until the lower-end edge of the inclined cover glass  202   a  contacts the second end portion of the glass slide  207 .  FIG. 8  illustrates the aforementioned state wherein the lower-end edge works as a fulcrum, and the suction pad  206  as a working point.  
      A push rod  210  is provided to the elevating member in a vertically movable manner. The inclined cover glass  202   a  is further deflected by the push rod  210  so as to bend it and then to have a larger inclined angle on the upper-end edge portion of the inclined cover glass  202   a  exceeding θ 3 . The push rod  210  is disposed to escape from far above the cover glass  202  during the pick up process shown in  FIG. 7 . When the elevating member (not shown) moves downward to affix the cover glass  202   a  to the glass slide  207 , push rod drive means (not shown) operates such that the push rod  210  moves downwards to bend and to push the cover glass  202   a  toward the glass slide  207 .  
      Consequently, the cover glass  202   a  has been progressively pushed onto the glass slide  207  from one side thereof while being bent due to the descent of the push rod  210  and the suction pad  206 . Upon the completion of pushing, the suction pad  206  and the push rod  210  both ascend, thereby completing the sealing operation.  
      As described above, the cell sample piece  208  can be sealed between the glass slide  207  and the cover glass  202   a  without the inclusion of air bubbles.  
      In the case of the publicly known cover glass transfer device mentioned above, the top cover glass can be picked up, one at a time, by separating and dropping the adjacent lower cover glass and then be transferred onto a glass slide without the inclusion of air bubbles between the glass slide and the cover glass.  
      However, in the case where the cover glass separating metal tool and the cover glass separating pawl are used to make a difference of radius of curvature between adjacent cover glasses to have the lower cover glass separated due to its own weight, the falling lower cover glass may not return onto the normal stacking position as getting stuck on the edge or the side wall of a case. Especially when the number of cover glass stacked in layers in the case becomes small, the falling distance becomes large such that the possibility that the cover glass does not return to the normal stacking position becomes higher. When the holding rod descends while the cover glass is being stuck inside of the case, the holding rod pushes and breaks the stuck cover glass.  
     SUMMARY OF THE INVENTION  
      The present invention has been made in view of the aforementioned problems of the conventional technique. An object of the present invention is to provide a cover glass transfer device always capable of maintaining a cover glass to be separated off to the normal stacking position.  
      In the case of the publicly known cover glass transfer device, in addition to members for transferring a cover glass, a separating metal tool and a separating pawl for separating a cover glass off are provided on the upper part of the opening edge part of a case such that the device tends to be large in size. The present invention has been made in view of the aforementioned problems, therefore, another object of the present invention is to provide a cover glass transfer device which can be downsized as there is no need to provide additional members above the case.  
      According to a first aspect of the present invention, a cover glass transfer device for a sample sealing apparatus performing the steps of: sequentially picking up a top cover glass of a plurality of cover glasses stacked in layers by picking up means; and affixing the picked up cover glass onto a glass slide to seal a sample on the glass slide, wherein the picking up means has: an elevating member capable of moving up and down above the plurality of cover glasses stacked in layers; a holding member movable up and down for a certain stroke with respect to the elevating member, the holding member having a suction member for vacuuming the cover glass at its distal end, the suction member coming into contact with the upper face of the top cover glass on a first end side; and a push member movable up and down for a certain stroke with respect to the elevating member, the push member being attached while provided with a downward pressure, the lower end part of the push member coming into contact with the top cover glass at a position between the sucked portion with the suction member and the portion of the cover glass on a second end side, and wherein after the holding member and the push member come into contact with the top cover glass due to the descent of the elevating member the holding member ascends together with the elevating member prior to the push member upon the initiation of ascent of the elevating member so as to change a curvature of the cover glass by allowing the one end of the cover glass which is not held by the suction member to bring in to contact with an adjacent lower cover glass to deflect the cover glass downward, and then the push member is allowed to ascend together with the elevating member in an integrated manner.  
      According to a second aspect of the present invention, in the device of the first aspect, the plurality of cover glasses are stacked in layers at an inclined angle such that a portion of the cover glass opposite to the suction member is positioned below a portion of the cover glass opposite to the push member.  
      According to a third aspect of the present invention, in the device of the first or second aspect, the descending velocity of the elevating member is controlled in accordance with a stacked height of the plurality of cover glasses when the elevating member descends.  
      According to a fourth aspect of the present invention, in the device of any one of the first to third aspects, the cover glass is held by the holding member in a state where the held cover glass is separated from the adjacent lower cover glass stacked in layers by the ascent of the elevating member and an inclined posture of the cover glass is maintained by allowing the suction member to be placed at an upper position than that of the pushing member being in contact with the cover glass in rear of the suction member, and the elevating member descends toward the glass slide in order to affix the held cover glass onto the glass slide while maintaining the inclined posture thereof.  
      According to the first aspect of the invention, when an elevating member starts to ascend for picking up a cover glass, upward force acts on the first end side of the top cover glass held by suction with a suction member provided to a holding member, thereby providing downward working force by a push member, for example, onto the almost longitudinal center part of the cover glass. Thus, the cover glass is deflected downward in a state where one end of the cover glass is pushed onto the adjacent lower cover glass. As the curvature due to the deflection changes in accordance with the ascent of the elevating member, even when attaching to the top cover glass held by suction, the adjacent lower cover glass cannot follow the change of enlarging the deflection, thereby separating the adjacent lower cover glass.  
      At this time, the separation operation described above is carried out in the position of the top cover glass stacked in layers such that the cover glass separated off naturally falls on the normal position of the top cover glass. Accordingly, the effect can be obtained, wherein a cover glass is sequentially picked up without causing any trouble for the next picking-up.  
      Upon picking up a cover glass by an elevating operation of an elevating member, a cover glass which has been affixed can be separated off with a simple mechanism wherein a time shift is produced when a holding member and a push member ascend together with the elevating member.  
      Further, upon picking up a cover glass, the curvature of the cover glass held by suction is significantly varied such that the cover glass is separated off in the position of the top cover glass stacked in layers. Therefore, unlike the conventional technique, there is no need to provide a cover glass separating member above the opening edge part of the case and an inwardly convex rounded part R of the opening part of the case, thereby realizing the downsizing of the apparatus. The shape of the case is also simplified.  
      Suppose that a stand-by state is defined as that the suction face of the suction member provided at the distal end of a holding rod is positioned above the lower end of a push member. In this case, the timing when the suction member sucks the top cover glass upon the descent of the elevating member is delayed by the time period corresponding to the move of the height difference in accordance with an inclined angle of the placed top cover glass. According to the second aspect of the present invention, the top cover glass held with the holding rod by suction can be deflected in accordance with this delayed time period, thereby reliably separating an adjacent lower cover glass which has been affixed.  
      When the process for picking up a stacked cover glass proceeds, the stacking height is lowered such that a descending elevating member cannot stop at a given position due to an increase in acceleration. According to the third aspect of the present invention, however, the elevating member can reliably stop at a given position by decelerating the descending velocity of the elevating member when the stacking height is lowered.  
      According to the fourth aspect of the present invention, a cover glass held by suction is inclined by maintaining the state when the cover glass stacked in layers is picked up and is affixed to a glass slide. Thus, while maintaining the above posture of the cover glass, the cover glass is moved over the glass slide, and the elevating member is allowed to descend to bring the inclined lower end of the cover glass into contact with the second end side of the glass slide. Then, the elevating member is allowed to further descend slightly to deflect the cover glass downward convexly by pushing with the push member. As the elevating member further descends, the cover glass is affixed completely by gradually pushing the suction side thereof. After the suction member is opened to the atmosphere to release the sucking and holding, the affixation is completed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a view showing a cover glass transfer device for a sample sealing apparatus according to an embodiment of the present invention where the picking-up of a cover glass is started;  
       FIG. 2  is a view showing a first step of the cover glass pick up process;  
       FIG. 3  is a view showing a second step of the cover glass pick up process;  
       FIG. 4  is a view showing a third step of the cover glass pick up process;  
       FIG. 5  is a view showing a cover glass transfer device for a sample sealing apparatus according to an embodiment of the present invention where the cover glass is affixed;  
       FIG. 6  is a flow chart of the first step of the cover glass pick up process;  
       FIG. 7  is a view showing a conventional cover glass transfer device for a sample sealing apparatus where a cover glass is picked up; and  
       FIG. 8  is a view showing a conventional cover glass transfer device for a sample sealing apparatus where a cover glass is picked up. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The present invention will be hereinafter described with reference to the following embodiments shown in the drawings.  
      FIGS.  1  to  5  show preferred embodiments of the present invention. FIGS.  1  to  3  are front views of a cover glass pick up portion of a cover glass transfer device for a sample sealing apparatus, illustrating a process for picking up a cover glass from a case.  
      In the drawings, the reference numeral  101  denotes a cover glass housing case, and the reference numeral  102  denotes a cover glass. The case  101  of the present embodiment is provided with a base member, having an inclined angle θ 1 , at the bottom thereof such that the cover glasses  102  stacked in layers are housed at the inclined angle θ 1  where one longitudinally oriented end edge B of the cover glass  102  is raised. Edge B refers to the upper-end edge of an inclined cover glass  102 , and edge A refers to the lower end edge of the inclined cover glass  102 . The inclined angle θ 1  is an angle opposite in inclination to that of the conventional example shown in  FIG. 7 . The present case is such that a cover glass holding rod  103 , which will be described later, is disposed on the proximal side of the lower-end edge A of the inclined cover glass  102 .  
      The reference numeral  103  denotes the cover glass holding rod (to be hereafter simply referred to as a holding rod) for holding a cover glass by suction. The reference numeral  106  denotes a cover glass push rod (to be hereafter referred to as a PS rod). These rods are supported by an elevating member  107  in a manner in which they are movable up and down.  
      The elevating member  107  is driven by an elevating drive mechanism EL using, as a drive source, an elevating motor comprising a pulse motor for example. The control of the elevating drive mechanism EL is carried out by a control apparatus CA, which controls the whole structure of the sample sealing device. In an operational sequence of the sample sealing device, the elevating member  107  starts to descend due to a descending operation of the elevating drive mechanism EL. This is after a descent instruction is given to the elevating member  107  at a particular time after placing a glass slide on a glass slide placing base. Upon detection of a contacting pressure when a suction pad  105  contacts the cover glass  102 , the drive control is initiated. Incidentally, by driving the pulse motor to rotate a lead screw or the like, a ball screw provided to the elevating member  107  and the lead screw are screwed together to move the elevating member  107 .  
      In the state when the elevating member  107  has descended to its lowest position, a tip part of the holding rod  103 , and that of the PS rod  106 , can descend the distance necessary to contact a bottom wall part of the case  101  while being supported by the elevating member  107 .  
      The holding rod  103  and the PS rod  106  are inserted through insertion holes  107   a  and  107   b , respectively, which are formed in the elevating member  107  in a vertical direction thereof. In the state when the elevating member  107  is disposed above the case  101 , the insertion hole  107   a  is positioned above the edge A of the cover glasses  102  stacked in layers in the case  101 , and the holding rod  103  is inserted therethrough ( 107   a ). Additionally, the insertion hole  107   b  is positioned above edge B of the cover glasses  102  stacked in layers in the case  101 , and the PS rod  106  is inserted therethrough ( 107   b ). Stopper rings  108   a  and  108   b , capable of coming into contact with the upper face of the elevating member  107 , are fixed on the upper part of the holding rod  103  and the PS rod  106 , respectively. These stopper rings  108   a  and  108   b  separately control the lower parts of the holding rod  103  and the PS rod  106 .  
      On the lower parts of the holding rod  103  and the PS rod  106 , spring fixation rings  109   a  and  109   b  are separately fixed below the lower face of the elevating member  107 . Between the lower face of the elevating member  107  and the spring fixation ring  109   a  of the holding rod  103 , a holding rod spring  104   a  consisting of a compressed coil spring is elastically installed. Also, between the lower face of the elevating member  107  and the spring fixation ring  109   b  of the PS rod  106 , a PS rod spring  104   b  consisting of a compressed coil spring is elastically installed.  
      Thus, the holding rod  103  and the PS rod  106  are independently supported and guided in a slidable manner, in a vertical direction, between the stopper rings  108   a  and  108   b  and the spring fixation rings  109   a  and  109   b , respectively. At the same time they are biased downward by the spring force of each of the compressed coil springs, the holding rod spring  104   a  and the PS rod spring  104   b.    
      The holding rod  103  is formed to be hollow inside. The upper end part thereof is led to a vacuum pump so as to be switched to between the vacuum pump and the atmospheric side via an electromagnetic switching valve (not shown). The switching valve is normally connected to the vacuum pump and is controlled to be switchable to the atmospheric side at the end of the process, wherein a cover glass has been attached as an addition.  
      On the lower end part of the holding rod  103  a cover glass suction pad  105  (to be hereafter referred to as a suction pad), which is rotatable due to a bent neck part of a hinged part thereof, is fixed. The suction pad  105  can attach to a cover glass  102 , when in a vacuum condition by means of the aforementioned vacuum pump, when the suction face of the suction pad  105  comes into contact with the cover glass  102 .  
      On the lower end part of the PS rod  106 , a cap  106   a —a protecting member made of a hard rubber, for example—is provided in order to protect the cover glass  102  from damage when the PS rod comes into contact therewith. Further, the PS rod  106  is provided with a pressure sensor S on the lower end part of the PS rod, which detects a pushing pressure onto a cover glass. A detection signal, generated by the pressure sensor S, is transmitted to the control apparatus CA as shown in  FIG. 2  such that the appropriate drive control of the elevating drive mechanism EL is carried out based on the detection signal. The pressure sensor S may be provided on the axis part of the PS rod  106 , rather than on the lower end part thereof.  FIG. 1  shows a first step of a cover glass pick-up process.  
      At the beginning, when the cover glass pick-up process is initiated, the elevating member  107  is in a stand-by state in which it is disposed above the case  101 . In this state the holding rod  103  and the PS rod  106 , inserted through the elevating member  107 , have been separately pushed down by means of the spring force of the holding rod spring  104   a  and the PS rod spring  104   b , respectively, to the position where the stopper rings  108   a  and  108   b  of these rods have come into contact with the upper face of the elevating member  107 . This state, as shown in  FIG. 1 , is defined as a stand-by state. In the above stand-by state, the holding rod  103  and the PS rod  106  are set such that the position of the suction face of the suction pad  105  provided on the lower end part of the holding rod  103  is higher in elevation than the lower end part of the cap  106   a  provided on the lower end part of the PS rod  106 . Further, the PS rod  106  is set to come into contact with an almost central part (in a longitudinal direction) of a cover glass when descending toward the case  101 .  
      When the elevating member  107  starts to descend from its position in the stand-by state, the cap  106   a  fixed on the push rod  106  (which descends on the side of the edge B of the cover glasses  102  stacked in layers) comes into contact with a cover glass  102   a  before the suction pad  105  fixed on the lower end part of the holding rod  103 . This is due to their relative vertical positional relationship in the stand-by state, and the inclination of the cover glasses  102 .  
      If the elevating member  107  continues to further descend, the suction pad  105  fixed on the holding rod  103  comes into contact with a cover glass  102   a  as shown in  FIG. 2 . The series of operations wherein the elevating member  107  in the stand-by state starts to descend, and allows the holding rod  103  and the PS rod  106  to come into contact with the cover glass  102 , is controlled by the control apparatus CA in accordance with the flow chart shown in  FIG. 6 .  
      The elevating member  107  starts to descend at a velocity V 1  (S 1 ) and the control apparatus determines whether the pressure sensor S provided on the PS rod  106  detects the pressure generated when that the PS rod  106  comes into contact with the cover glass  102   a  within a predetermined time (T 1 ) (S 2 ). The elevating member  107  descends at a constant velocity, based on the determination that there is a long distance between the elevating member  107  and the cover glass  102   a  until the above pressure sensor S detects the aforementioned contacting pressure (S 3 ). After pressure is detected by the above pressure sensor S, the descent velocity of the elevating member  107  is slowed on the determination that there is now only a short distance between the elevating member  107  and the cover glass  102   a  (S 4 ). The elevating member  107  then stops its descent when the pressure sensor S of the suction pad  105  detects that the suction pad has attached by suction to the cover glass  102   a  (S 5 ).  
      The PS rod  106 , which has first come into contact with the cover glass  102   a , cannot further descend after its contact with the cover glass  102   a  such that only the elevating member  107  continues to descend with respect to the PS rod  106 . At this time, the PS rod spring  104   b  is compressed, thereby imparting a downward spring force on to the PS rod  106 .  
      As the elevating member  107  descends, the suction pad  105  of the holding rod  103  comes into contact with the cover glass  102   a , following contact by the PS rod  106 . Thereafter, the holding rod  103  cannot further descend such that only the elevating member  107  continues to descend with respect to the holding rod  103 . At this time, the holding rod spring  104   a  is compressed, thereby imparting a downward spring force on to the holding rod  103 . Therefore, the suction pad  105  attaches by suction to the cover glass  102   a.    
       FIG. 3  shows a second step of the cover glass pick-up process.  
      When the suction sensor detects that the cover glass  102   a  has been attached by suction, the elevating member  107  starts to ascend.  
      As the elevating member  107  ascends, the holding rod  103  starts to ascend together with the elevating member  107  after the stopper ring  108   a  fixed on the holding rod  103  has come into contact with the upper end face of the elevating member  107 . At this time, the cover glass  102   a  is held by suction from the suction pad  105  of the holding rod  103  near edge A of the cover glass  102   a . The cover glass  102   a  is subsequently lifted clockwise about fulcrum P, which is where edge B of the cover glass  102   a  contacts those cover glasses stacked in layers beneath it.  
      When the elevating member  107  further ascends from its position in the state described above, the cover glass  102   a  is lifted about fulcrum P by the attachment point of the suction pad  105 . At this time, the stopper ring  108   b  of the PS rod  106  has clearance with respect to the elevating member  107  such that the PS rod  106  is further biased downward by the PS rod spring  104   b , thereby providing a downward pressure to a contacting point Q—which is where the PS rod comes into contact with the cover glass  102   a.    
      Accordingly, the cover glass  102   a  is loaded having a fulcrum P on edge B thereof, a working point towards edge A to which an upward force is provided, and a working point (which is the contacting point on the PS rod  106 ) to which a downward force is provided. The result is that a large downward convex deflection is provided to the entire cover glass  102   a  by the contacting point of the PS rod  106  to the side of the suction pad  105 . The amount of this deflection becomes larger as the elevating member  107  ascends, such that the curvature of the cover glass  102   a  held by suction by the suction pad  105  gradually becomes large.  
      On the other hand, the upward force provided by the suction pad  105  to cover glass  102   a  is not provided to the adjacent lower cover glasses  102   b  thereunder. Therefore, the cover glasses  102   b  cannot follow the change in the radius of curvature created on the cover glass  102   a  attached to the suction pad  105 , thereby causing the separation of the adjacent lower cover glass  102   b  therefrom.  
      As shown in  FIG. 3 , the separation of the cover glass  102   b  is performed while the cover glass  102   a  remains in contact at its edge B with lower stacked layers of cover glasses  102   b . Thus, the adjacent lower separated cover glass  102   b  returns to, or remains in, its initial normal place in the stack to be subjected to the next pick-up by suction means. Therefore, unlike the conventional method, there is no need to provide a separating member above the opening edge part of the case  101  in order to separate an adjacent affixed cover glass. Also, there is no need to provide the curved part R on the opening edge part of the case  101  for guiding a separated cover glass  102   b  to its normal stacking position. As a result, the suction pad  105  can properly hold, by suction, a single cover glass  102   a  in a sequential order from the stack.  FIG. 4  shows a third step of the cover glass pick-up process.  
      As the elevating member  107  continues to ascend, and the stopper ring  108   b  fixed on the PS rod  106  comes into contact with the upper edge face thereof, the PS rod  106  starts to ascend together with the holding rod  103 . On being further lifted, the cover glass  102   a  separates from the top layer cover glass of the remaining cover glasses  102   b  stacked in layers. Then, the cover glass  102   a  recovers its flat state upon being released from deflection. At this time, since the cap  106   b  has been set to be disposed lower in elevation than the suction pad  105  (as described above), the cover glass  102   a  proceeds to a cover glass affixation process while being held by suction at an inclined angle θ 2 .  
       FIG. 5  shows the cover glass affixation process.  
       FIG. 5  shows the operational process to attach, as an addition, the cover glass  102   a  held by suction by the holding rod  103  to a glass slide  110  placed on a glass slide placing base (not shown). This is followed by sealing a cell sample piece  111  on the glass slide  110  with the aid of a sealing adhesive solution  112 .  
      The PS rod  106  inserted through the elevating member  107  is disposed at a position corresponding to a second end of the glass slide  110  onto which the adhesive solution was dropped. The side of the glass slide  110  onto which the adhesive solution  112  was dropped will be hereafter referred to as the “second end” of the glass slide  110 .  
      The holding rod  103  inserted through the elevating member  107  is disposed at a position corresponding to the other end of the glass slide  110 . The other side of the glass slide  110  onto which the adhesive solution  112  was dropped will be hereafter referred to as the “first end” of the glass slide  110 .  
      The cover glass  102   a , which is held by suction with the suction pad  105  of the holding rod  103  on the other end thereof, is contacted with the PS rod  106  at a point marked Q near its almost longitudinal center part. The cover glass  102   a  having one end thereof inclined downward at the inclined angle θ 2  descends toward the glass slide  110 .  
      When the elevating member  107  descends for a certain distance, edge B of the cover glass  102   a  comes into contact with the upper face of the one end of the glass slide  110 . Then, the elevating member  107  further descends slightly, and the cover glass  102   a  is provided with a downward convex deflection at a fulcrum S, and at a downward working point Q. When the cover glass  102   a  is bent by allowing the elevating member  107  to descend slightly, an inclined angle θ 2 ′ between the cover glass  102   a  and the glass slide  110  results. This angle θ 2 ′ is less than the inclined angle θ 2  when a cover glass  102   a  is held by suction by holding rod  103  in an unloaded condition. Consequently θ 2 ′&lt;θ 2 .  
      When the elevating member  107  further descends, the cover glass  102   a  is pushed toward, and is affixed to, the glass slide  110  by the PS rod  106  and the suction pad  105 . By thus pushing the cover glass  102   a  gradually, starting from the side where the adhesive solution  112  was dropped, the cell sample piece  111  is able to be sealed between the glass slide  110  and the cover glass  102   a  without the inclusion of air bubbles.  
      In the above embodiments, the cover glass  102   a  is picked up in the state where the cover glasses  102  are stacked in layers in the case  101  at the inclined angle θ 1 . However, the cover glasses  102  may be stacked horizontally, and may not be stacked in layers in the case  101 .  
      That is, in the case of stacking the cover glasses  102  horizontally, the holding rod  103  and the PS rod  106  descend from the position of their stand-by state described above while posturing at the above inclined angle θ 2 —which is an angle lowering toward the bottom right, and formed by a tangent line between the lower end of the cap  106   a  of the PS rod  106  and the suction face of the suction pad  105  fixed on the holding rod  103 . Firstly, the cap  106   a  of the PS rod  106  comes into contact with the top cover glass  102 , and then the suction pad  105  of the holding rod  103  comes into contact with the top cover glass  102 .  
      Also in this case, the stopper ring  108   a  of the holding rod  103  first comes into contact with the upper face of the elevating member  107 , allowing the holding rod  103  to move upward when the elevating member  107  starts to ascend. Then, the PS rod  103  pushes the cover glass  102  downward at the almost longitudinal center part of the cover glass  102 , thereby deflecting downward the cover glass  102  at a fulcrum, the one end thereof, to change the curvature of the cover glass  102 . Therefore, the cover glass  102   a  is naturally separated from adjacent lower cover glasses in the stack.  
      When the cover glasses  102  are stacked in layers in an inclined state or horizontally, the separating operation of the top cover glass  102   a  is carried out in the state that the cover glass  102   a  comes into contact with the second end of the adjacent lower cover glass  102   b . It is merely necessary to stack a plurality of cover glasses  102  in layers, without any need to accommodate them in a container-like case.