Patent Publication Number: US-2021178525-A1

Title: Pillar delivery method, method for manufacturing glass panel unit, and pillar delivery apparatus

Description:
TECHNICAL FIELD 
     The present disclosure relates to a pillar delivery method, a method for manufacturing a glass panel unit, and a pillar delivery apparatus. 
     BACKGROUND ART 
     Patent Literature 1 discloses a known technique for delivering a plurality of pillars (or spacers) onto a single substrate (glass pane) during a manufacturing process of glass panel units. An internal space is formed by bonding another substrate onto the substrate on which the pillars have been delivered. Then, the internal space is sealed in an evacuated condition, thereby manufacturing a glass panel unit with excellent thermal insulation properties. 
     According to the known technique mentioned above, the plurality of pillars are made by subjecting a thin plate to a punching process. The plurality of pillars thus made are once stocked. When glass panel units are manufactured, some of those pillars needed for the manufacturing process are taken out of the stock and placed on the substrate. 
     Thus, according to the known technique, the pillars made by punching tend to have burr. In addition, the pillars need to be once stocked, which increases the number of manufacturing process steps and decreases the efficiency of manufacturing. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP H11-79799 A 
     SUMMARY OF INVENTION 
     An object of the present disclosure is to provide a pillar delivery method, a method for manufacturing a glass panel unit, and a pillar delivery apparatus, all of which are configured or designed to efficiently deliver, onto a substrate, a plurality of pillars with significantly reduced burr. 
     A pillar delivery method according to an aspect is a method for delivering a plurality of pillars onto a substrate, including a glass panel, to manufacture a glass panel unit. The method includes: an irradiation step including setting, over a holder, a sheet for use to form pillars and irradiating the sheet with a laser beam to punch out the plurality of pillars; a holding step including having the plurality of pillars, which have been punched out of the sheet, held by the holder; and a mounting step including picking up some or all of the plurality of pillars from the holder and mounting the pillars onto the substrate. 
     A method for manufacturing a glass panel unit according to another aspect includes: a pillar delivery step including delivering the plurality of pillars onto the substrate by the pillar delivery method described above; an arrangement step including laying a counter substrate, including a glass panel, over the substrate; a bonding step including bonding respective peripheral edges of the substrate and the counter substrate together to form an internal space where the plurality of pillars are located; an evacuation step including evacuating the internal space; and a sealing step including sealing the internal space while keeping the internal space evacuated. 
     A pillar delivery apparatus according to still another aspect is an apparatus for delivering a plurality of pillars onto a substrate, including a glass panel, to manufacture a glass panel unit. The apparatus includes: a holder; a sheet for use to form pillars to be set over the holder; a laser cutter to punch out the plurality of pillars of the sheet by irradiating the sheet with a laser beam; and a mounter to pick up some or all of the plurality of pillars held by the holder and mount the pillars onto the substrate. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view schematically illustrating a pillar delivery apparatus for use in a method for manufacturing a glass panel unit according to an exemplary embodiment; 
         FIG. 2  is a partially cutaway side view illustrating how a principal part of the pillar delivery apparatus works while irradiating the workpiece with a laser beam; 
         FIG. 3  is a plan view illustrating a main part of a sheet included in the pillar delivery apparatus; 
         FIG. 4  is a partially cutaway side view illustrating how a principal part of the pillar delivery apparatus works while suctioning a plurality of pillars; 
         FIG. 5  is a plan view illustrating a first stage of transportation of a holder by the pillar delivery apparatus; 
         FIG. 6  is a plan view illustrating a second stage of transportation of the holder by the pillar delivery apparatus; 
         FIG. 7A  is a partially cutaway side view illustrating how a principal part of the pillar delivery apparatus works while picking up a plurality of pillars; 
         FIG. 7B  is a side view illustrating how a principal part of the pillar delivery apparatus works while mounting the plurality of pillars; 
         FIG. 8  is a perspective view illustrating an arrangement step of the manufacturing method; 
         FIG. 9  is a plan view illustrating a bonding step of the manufacturing method; 
         FIG. 10  is a cross-sectional view thereof taken along a plane A-A shown in  FIG. 9 ; 
         FIG. 11A  is a cross-sectional view of a principal part illustrating an evacuation step of the manufacturing method; 
         FIG. 11B  is a cross-sectional view of a principal part illustrating a sealing step of the manufacturing method; 
         FIG. 12  is a perspective view illustrating a glass panel unit manufactured by the manufacturing method; 
         FIG. 13  is a partially cutaway side view illustrating how a principal part of a pillar delivery apparatus according to a first variation works while irradiating the workpiece with a laser beam; 
         FIG. 14  is a plan view schematically illustrating a pillar delivery apparatus according to a second variation; 
         FIG. 15  is a plan view illustrating how the pillar delivery apparatus according to the second variation transports a holder; 
         FIG. 16  is a plan view schematically illustrating a pillar delivery apparatus according to a third variation; and 
         FIG. 17  is a plan view illustrating how the pillar delivery apparatus according to the third variation transports a holder. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Exemplary Embodiment 
     A method for manufacturing a glass panel unit according to an exemplary embodiment will be described with reference to the accompanying drawings. The method for manufacturing a glass panel unit according to the exemplary embodiment includes a pillar delivery step, an arrangement step, a bonding step, an evacuation step, and a sealing step. 
     The pillar delivery step is the step of delivering a plurality of pillars  3  onto a substrate  91  including a glass panel  910 . 
     The pillar delivery step includes: forming a plurality of pillars  3  at a location near the substrate  91  using the pillar delivery apparatus  8  schematically shown in  FIGS. 1-7 ; having the plurality of pillars  3  just formed held by a holder  1  under the pillar delivery apparatus  8 ; transporting the holder  1  in its entirety to the vicinity of a mounting location with the plurality of pillars  3  still held thereon; and then picking up some or all of the plurality of pillars  3  and mounting the pillars  3  onto the substrate  91 . The pillar delivery step will be described in further detail later. 
     The arrangement step includes arranging another substrate  92  including a glass panel  920  (hereinafter referred to as a “counter substrate  92 ”) with respect to the substrate  91  on which the plurality of pillars  3  have been mounted such that the counter substrate  92  is laid over the plurality of pillars  3  (see  FIG. 8 ), thus sandwiching the plurality of pillars  3  between the pair of substrates  91 ,  92 . Before the substrate  92  is laid over the substrate  91 , a sealing member  94  in a frame shape is arranged on the upper surface of the substrate  91 . The sealing member  94  may be glass paste, for example. 
     The sealing member  94  may be arranged either after the plurality of pillars  3  have been mounted onto the substrate  91  or before the plurality of pillars  3  are mounted onto the substrate  91 , whichever is appropriate. Alternatively, mounting the plurality of pillars  3  on the substrate  91  and arranging the sealing member  94  on the substrate  91  may be performed in parallel with each other. 
     The bonding step includes hermetically bonding respective peripheral edges of the substrates  91 ,  92  together with the sealing member  94  in the frame shape. This allows an internal space S 1  to be formed between the pair of substrates  91 ,  92  that are arranged to face each other and the sealing member  94 . The plurality of pillars  3  are located in the internal space S 1  (see  FIGS. 9 and 10 ). 
     The plurality of pillars  3  are positioned to abut on the respective surfaces, facing each other, of the pair of substrates  91 , 92 . The plurality of pillars  3  are located in a region surrounded with the sealing member  94  in the frame shape to serve as spacers that maintain a predetermined gap distance between the pair of substrates  91 ,  92 . 
     The evacuation step includes evacuating the internal space S 1  through an evacuation port  95  provided through the substrate  92  (see  FIG. 11A ). In the evacuation step, a sealant  96  and a plate  97  are inserted in this order into the evacuation port  95  to evacuate the internal space S 1 . The sealant  96  may be a solid sealant made of a glass frit, for example. 
     Next, an evacuation head  98  is pressed against a region, surrounding the opening of the evacuation port  95 , of the substrate  92  to maintain an airtight condition with respect to the substrate  92 . At this time, the sealant  96  and the plate  97  are forced elastically toward the substrate  91  by a spring mechanism  99  that the evacuation head  98  includes. 
     Sucking the air up from inside the evacuation head  98  in this state (as indicated by the open arrow in  FIG. 11A ) causes the air in the internal space S 1  to be evacuated through the evacuation port  95 . 
     The sealing step includes sealing the internal space S 1  up with the sealant  96  while keeping the internal space S 1  evacuated (see  FIG. 11B ). 
     The sealing step includes softening the sealant  96  by locally heating the sealant  96 . The sealant  96  may be locally heated by, for example, being irradiated with an infrared ray or a laser beam or being inductively heated. The sealant  96  that has been softened by being locally heated is deformed inside the internal space S 1  under the biasing force applied by the spring mechanism  99 . The sealant  96  thus deformed seals the evacuation port  95  up. 
     A glass panel composite is formed through these manufacturing process steps. The glass panel composite may be provided as glass panel unit with excellent thermal insulation properties (see  FIG. 12 ). Optionally, another glass substrate may be further stacked on top of the glass panel composite formed through the same manufacturing process steps and the stack may be provided as a glass panel unit. Alternatively, part of the glass panel composite formed through the same manufacturing process steps may be cut off and the rest may be provided as a glass panel unit. 
     Next, the pillar delivery step will be described in detail with reference to  FIGS. 1-7 . 
     The pillar delivery step includes forming a plurality of pillars  3  by laser cutting and sequentially delivering the plurality of pillars  3  thus formed onto the substrate  91  using the pillar delivery apparatus  8 . 
     First, the structure of the pillar delivery apparatus  8  will be described. The pillar delivery apparatus  8  includes a holder  1 , a transport mechanism  7 , a sheet  2 , a laser cutter  4 , and a mounter  5 . The pillar delivery apparatus  8  further includes a supporting mechanism  6  for supporting the substrate  91  such that the substrate  91  is displaceable along a first axis A 1 . The first axis A 1  is a virtual axis that extends linearly in a plan view (i.e., when the pillar delivery apparatus  8  is viewed from over the apparatus). 
     The holder  1  includes: a body  10  including a porous material; and a suctioning mechanism  11  with the ability to have the plurality of pillars  3  suctioned onto the body  10  (see, for example,  FIG. 2 ). 
     The upper surface of the body  10  is provided with a plurality of grooves  105 . Each of the grooves  105  is a bottomed groove, of which the upside is open. The plurality of grooves  105  are arranged in matrix on the upper surface of the holder  1  (i.e., on the upper surface of the body  10 ) to be spaced apart from each other. 
     The suctioning mechanism  11  includes an air sucking device  112  connected to the body  10 . The air sucking device  112  may be implemented as, for example, an air sucking fan. The air sucking device  112  is configured to suck the air up through a part of the holder  1 . More specifically, the air sucking device  112  is configured to suck up the air from inside micropores that the body  10  has. Activating the air sucking device  112  causes the pillars  3  in the grooves  105  to be suctioned onto the inner surface of the grooves  105  (see, for example,  FIG. 4 ). 
     The transport mechanism  7  includes: a delivery stage  75  for supporting the holder  1  thereon; a supporting portion  71  (see, for example,  FIG. 5 ) for supporting the delivery stage  75  such that the delivery stage  75  is movable along a second axis A 2 ; and a displacement operating member  72  (see  FIG. 6 ) for displacing the delivery stage  75  along the first axis A 1 . The second axis A 2  is a virtual axis extending linearly and perpendicularly to the first axis A 1  in a plan view (i.e., when the pillar delivery apparatus  8  is viewed from over the apparatus). 
     The sheet  2  is a flexible sheet for use to form the plurality of pillars  3 . The sheet  2  is suitably made of a resin (such as polyimide) but may also be made of a metallic material. 
     The sheet  2  is wound around a pair of rollers  29 , which are arranged to be spaced from each other, and given tension between the pair of rollers  29  (see  FIG. 2 ). The sheet  2  and the rollers  29  that support the sheet  2  are spaced apart from each other in a direction aligned with the second axis A 2  with respect to the substrate  91 . 
     The laser cutter  4  is arranged to be spaced apart from the substrate  91  in a direction aligned with the second axis A 2 . The laser cutter  4  is located over the pillar forming sheet  2 . The laser cutter  4  is configured to radiate a laser beam downward (i.e., toward the sheet  2 ). 
     The mounter  5  includes a mounting head  51  and a supporting portion  53  for supporting the mounting head  51  such that the mounting head  51  is movable along the second axis A 2 . The mounting head  51  and the supporting portion  53  are arranged over the substrate  91 . The mounting head  51  includes a plurality of suction nozzles  515  (see  FIGS. 7A and 7B ). Each of the plurality of suction nozzles  515  has a tip opening and sucks the air up through the tip opening, thereby suctioning one of the pillars  3  onto the tip opening. Each of the plurality of suction nozzles  515  lets the air out through the tip opening thereof to release the pillar  3  that has been suctioned onto the tip opening. 
     Next, it will be described how to perform the pillar delivery step using the pillar delivery apparatus  8  described above. In other words, it will be described how to perform the pillar delivery method. The pillar delivery step includes an irradiation step, a holding step, a transporting step, and a mounting step. 
     The irradiation step includes setting the sheet  2  on the holder  1  at a location adjacent to the substrate  91  in the direction aligned with the second axis A 2  and positioning the laser cutter  4  over the sheet  2 . At this time, part of the sheet  2  is suitably pressed against the upper surface of the holder  1  by a pressing member  15 . 
     In the irradiation step, the plurality of grooves  105  of the holder  1  are located under the sheet  2 . That is to say, the plurality of grooves  5  are covered with the sheet  2  at the top. 
     In this state, the sheet  2  is irradiated at multiple points with a laser beam emitted from the laser cutter  4 , thereby making annular cuts  21  at the multiple points on the sheet  2 . The cuts  21  run through the sheet  2  along the thickness thereof (i.e., in the upward/downward direction). This allows portions  23  surrounded with the cuts  21  to be punched out of the sheet  2  (see  FIG. 3 ). The plurality of portions  23  punched out of the sheet  2  constitute the plurality of pillars  3 . 
     The plurality of circular columnar portions  23  punched out of the sheet  2  (i.e., the plurality of pillars  3 ) fall by themselves due to their own weight into the plurality of grooves  105  located under those portions  23 . 
     Performing this irradiation step allows the plurality of pillars  3 , of which the entire periphery has been subjected to the laser cutting process, to be put one to one into the plurality of grooves  105  that the holder  1  has (see, for example,  FIG. 4 ). 
     The holding step includes having the plurality of pillars  3 , which have been cut out and have fallen into the plurality of grooves  105 , suctioned onto the holder  1  by a negative pressure produced by the air sucking device  112  such that the plurality of pillars  3  are held one to one in the plurality of grooves  105 . The air sucking device  112  may be activated either during the irradiation step (i.e., while the pillars  3  are being formed by laser cutting) or after the irradiation step has been finished, whichever is appropriate. 
     Alternatively, the air sucking device  112  may be provided for the delivery stage  75 , instead of the holder  1 . In that case, the air sucking device  112  needs to be arranged at such a position where the air sucking device  112  may suck up the air in micropores of the holder  1  with the holder  1  placed on the delivery stage  75 . 
     In the transporting step, the delivery stage  75  for supporting the holder  1  from under the holder  1  horizontally moves the holder  1  and the plurality of pillars  3  held by the holder  1 . 
     For example, first, the delivery stage  75  moves along the second axis A 2  to a position over the substrate  91  as shown in  FIG. 5 . Next, the delivery stage  75  moves along the first axis A 1  toward the mounter  5  as shown in  FIG. 6 . 
     That is to say, the transport mechanism  7  transports the holder  1  and the plurality of pillars  3  held by the holder  1  along the second axis A 2  to a position over the substrate  91  and then transports the holder  1  and the plurality of pillars  3  along the first axis A 1  toward the mounter  5  by driving the delivery stage  75 . 
     During this transporting step, the air sucking device  112  is suitably activated continuously. That is to say, the holder  1  is suitably transported to the vicinity of a location where the plurality of pillars  3  are mounted while the plurality of pillars  3  are suctioned onto the upper surface of the holder  1 . In the vicinity of the location where the plurality of pillars  3  are mounted, the mounting head  51  of the mounter  5  is located. 
     The mounting step includes picking up the plurality of pillars  3  from the holder  1  thus transported and mounting the plurality of pillars  3  onto the upper surface of the substrate  91  using the mounter  5 . 
     Specifically, the plurality of suction nozzles  515  of the mounting head  51  suctions and lifts the plurality of pillars  3  held in the plurality of grooves  105  in the holder  1  (see  FIG. 7A ). At this time, the air sucking device  112  is suitably deactivated. 
     Next, at least one of the mounting head  51  or the substrate  91  is moved. At a timing when the plurality of pillars  3  reach the target positions with respect to the substrate  91 , the plurality of pillars  3  are released from the mounting head  51  to be mounted onto the upper surface of the substrate  91  (see  FIG. 7B ). 
     In the pillar delivery step, the irradiation step, the holding step, the transporting step, and the mounting step described above are performed repeatedly, thereby delivering the plurality of pillars  3  onto the upper surface of the substrate  91  such that the pillars  3  are placed at their respective predetermined positions. 
     The respective pillars  3  delivered onto the substrate  91  will have significantly reduced burr, because the pillars  3  are portions  23  that have been punched out of the sheet  2  by laser cutting. In addition, the plurality of pillars  3  are formed in the vicinity of the substrate  91  and sequentially mounted onto the substrate  91 . This eliminates the need to form a plurality of pillars  3  by laser cutting at one location and then stock the pillars  3  at another location. This allows the plurality of pillars  3  to be efficiently delivered onto the substrate  91 . 
     (Variations) 
     As will be described by way of illustrative examples, the glass panel unit manufacturing method, pillar delivery method, and pillar delivery apparatus  8  described above may be modified as appropriate in various manners depending on a design choice or any other factor. In the following description, any constituent element, having the same function as a counterpart of the exemplary embodiment described above, will be designated by the same reference numeral as that counterpart&#39;s, and a detailed description thereof will be omitted herein. 
     For example, according to the method for manufacturing a glass panel unit described above, arrangement of a getter that may adsorb gas molecules is omitted. However, this is only an example of the present disclosure and should not be construed as limiting. Alternatively, the getter may be arranged in the internal space S 1 . 
     Also, according to the method for manufacturing a glass panel unit described above, the evacuation port  95  for evacuating the internal space S 1  is provided through the substrate  92 , out of the pair of substrates  91 ,  92 . However, this is only an example of the present disclosure and should not be construed as limiting. Alternatively, the evacuation port  95  may be provided through the substrate  91 . 
     Furthermore, in the sealing step of the method for manufacturing a glass panel unit described above, the internal space S 1  is sealed up by locally heating the sealant  96  inserted into the evacuation port  95 . However, this is not the only means for sealing the internal space S 1 . Alternatively, part of the sealing member  94  for hermetically bonding the pair of substrates  91 ,  92  together may be deformed by heating, for example, with the internal space S 1  kept evacuated and the internal space S 1  may be sealed with the deformed part of the sealing member  94 . Still alternatively, a glass tube may be connected to the substrate  92  to communicate with the evacuation port  95 , the internal space S 1  may be evacuated through the glass tube, and then the glass tube may be sealed by heating, for example. 
     Furthermore, in the pillar delivery apparatus  8  described above, the holder  1  includes both the suctioning mechanism  11  and the plurality of grooves  105 . However, the holder  1  does not have to include both the suctioning mechanism  11  and the plurality of grooves  105 . Alternatively, the pillar delivery apparatus  8  may include either the suctioning mechanism  11  or the plurality of grooves  105 . 
     For example, if the holder  1  includes the suctioning mechanism  11  but has no grooves  105 , then the holder  1  may have a flat upper surface. In that case, the plurality of pillars  3  put on the flat upper surface may be transported while being suctioned onto the holder  1  by a negative pressure produced by the air sucking device  112 . 
     If the holder  1  has the plurality of grooves  105  but does not include the suctioning mechanism  11 , then the plurality of pillars  3  may be transported while being put in the plurality of grooves  105 . 
     Furthermore, the pillar delivery apparatus  8  described above includes a single holder  1 , a single delivery stage  75 , a single sheet  2 , a single laser cutter  4 , and a single mounter  5 . However, the number of each of these members provided does not have to be one. If the number of each of these members provided is plural, then the plurality of pillars  3  may be formed by laser cutting at multiple locations adjacent to the substrate  91  and those pillars  3  formed at the respective locations may be sequentially delivered onto the substrate  91 . 
     Furthermore, in the pillar delivery apparatus  8  described above, the body  10  has porosity. Alternatively, as in a first variation illustrated in  FIG. 13 , an air sucking path  13  communicating with each of the plurality of grooves  105  may be provided inside the body  10  and may be connected to the air sucking device  112 . The air sucking path  13  suitably communicates with the bottom of each groove  105 . 
     Furthermore, in the pillar delivery apparatus  8  described above, the holder  1  that holds the plurality of pillars  3  thereon is transported via the delivery stage  75 . Alternatively, the holder  1  may also be transported without using the delivery stage  75  as in a second variation shown in  FIGS. 14 and 15 . The holder  1  is suitably transported by an appropriate transport mechanism but may be moved manually by the operator. 
     According to the second variation, the mounter  5  includes an attachment portion  55  to which the holder  1  is attachable removably. The mounting head  51  and the attachment portion  55  are coupled to the supporting portion  53  to be movable along the second axis A 2 . The supporting portion  53  is displaceable along the first axis A 1  with respect to the substrate  91 . 
     Thus, the mounting head  51  and the attachment portion  55  (and the holder  1  attached to the attachment portion  55 ) are displaceable along the first axis A 1  and the second axis A 2  with respect to the substrate  91 . The holder  1  attached to the attachment portion  55  is displaceable along the first axis A 1  with respect to the mounting head  51 . 
     In the second variation, an exchange stage  77  is provided adjacent to the substrate  91  in the direction aligned with the first axis A 1 . The holder  1  for holding the plurality of pillars  3  is transported from under the laser cutter  4  and the sheet  2  to a location near the exchange stage  77  and transferred onto the exchange stage  77  (see  FIG. 15 ). 
     The holder  1  transferred onto the exchange stage  77  (i.e., the holder  1  that currently holds the plurality of pillars  3  thereon) may be exchanged with another holder  1  attached to the mounter  5  (i.e., the holder  1  from which the plurality of pillars  3  have been picked up by the mounting head  51 ). 
     According to the second variation, repeatedly performing the step of sequentially delivering the holder  1  that currently holds the plurality of pillars  3  thereon onto the exchange stage  77  and exchanging the holder  1  with another holder  1  attached to the mounter  5  allows the plurality of pillars  3  to be delivered efficiently onto the substrate  91 . 
     Optionally, the laser cutting may be performed with the holder  1  attached to the mounter  5  as in a third variation shown in  FIGS. 16 and 17 . 
     According to the third variation, the mounter  5  includes an attachment member  57  to which the holder  1  may be attached. The mounting head  51  and the attachment member  57  are coupled to the supporting portion  53  to be movable along the second axis A 2 . The supporting portion  53  is displaceable along the first axis A 1 . 
     Thus, the mounting head  51  and the attachment member  57  (and the holder  1  attached to the attachment member  57 ) are movable along the first axis A 1  and the second axis A 2  with respect to the substrate  91 . The holder  1  attached to the attachment member  57  is displaceable along the first axis A 1  with respect to the mounting head  51 . 
     In the third variation, the laser cutter  4  and the sheet  2  are arranged at a location adjacent to the substrate  91  in the direction aligned with the first axis A 1 . 
     According to the third variation, with the holder  1  attached to the mounter  5 , the irradiation step is performed at a location adjacent to the substrate  91  (see  FIG. 16 ). In the transporting step, the mounter  5  is transported in its entirety along the first axis A 1  with the holder  1  that holds the plurality of pillars  3  still attached thereto (see  FIG. 17 ). In the mounting step, the mounter  5  that has transported picks up the plurality of pillars  3  from the holder  1  and mounts the pillars  3  onto the substrate  91 . The third variation achieves the advantages of facilitating the use of an existent facility and reducing the overall installation area of the pillar delivery apparatus  8 . 
     (Implementations) 
     As can be seen from the foregoing description of embodiments and their variations, a first implementation of a pillar delivery method has the following features: 
     A first implementation of the pillar delivery method is a method for delivering a plurality of pillars ( 3 ) onto a substrate ( 91 ), including a glass panel ( 910 ), to manufacture a glass panel unit. The method includes an irradiation step, a holding step, and a mounting step. The irradiation step includes setting, over a holder ( 1 ), a sheet ( 2 ) for use to form pillars and irradiating the sheet ( 2 ) with a laser beam to punch out the plurality of pillars ( 3 ). The holding step includes having the plurality of pillars ( 3 ), which have been punched out of the sheet ( 2 ), held by the holder ( 1 ). The mounting step includes picking up some or all of the plurality of pillars ( 3 ) from the holder ( 1 ) and mounting the pillars ( 3 ) onto the substrate ( 91 ). 
     The pillar delivery method according to the first implementation allows a plurality of pillars ( 3 ), made by laser cutting with burr reduced significantly, to be efficiently delivered onto the substrate ( 91 ). 
     A second implementation of the pillar delivery method, which may be adopted in combination with the first implementation, has the following additional features. The pillar delivery method according to the second implementation further includes a transporting step. The transporting step includes transporting the holder ( 1 ) in its entirety with all of the plurality of pillars ( 3 ) still held by the holder ( 1 ). The mounting step includes picking up some or all of the plurality of pillars ( 3 ) from the holder ( 1 ) transported and mounting the pillars ( 3 ) onto the substrate ( 91 ). 
     The pillar delivery method according to the second implementation allows a plurality of pillars ( 3 ), made by laser cutting with burr reduced significantly, to be transported to the mounting location while being still held by the holder ( 1 ) and efficiently delivered onto the substrate ( 91 ). 
     A third implementation of the pillar delivery method, which may be adopted in combination with the first or second implementation, has the following additional features. In the pillar delivery method according to the third implementation, the holding step includes having the plurality of pillars ( 3 ), which have been punched out of the sheet ( 2 ), suctioned onto, and thereby held by, the holder ( 1 ). 
     The pillar delivery method according to the third implementation allows the plurality of pillars ( 3 ), which have been punched out of the sheet ( 2 ) by laser cutting, to be held with good stability by the holder ( 1 ). 
     A fourth implementation of the pillar delivery method, which may be adopted in combination with the third implementation, has the following additional features. In the pillar delivery method according to the fourth implementation, the holding step includes having the plurality of pillars ( 3 ) suctioned onto the holder ( 1 ) by sucking up the air through the holder ( 1 ). 
     The pillar delivery method according to the fourth implementation allows the plurality of pillars ( 3 ), which have been punched out of the sheet ( 2 ) by laser cutting, to be held with good stability by the holder ( 1 ) by sucking the air up. 
     A fifth implementation of the pillar delivery method, which may be adopted in combination with the fourth implementation, has the following additional features. In the pillar delivery method according to the fifth implementation, the holder ( 1 ) includes a body ( 10 ) with porosity. 
     The pillar delivery method according to the fifth implementation allows the plurality of pillars ( 3 ) to be held with good stability by the holder ( 1 ) by sucking the air up through the body ( 10 ) with porosity. 
     A sixth implementation of the pillar delivery method, which may be adopted in combination with the fourth implementation, has the following additional features. In the pillar delivery method according to the sixth implementation, the holder ( 1 ) includes a body ( 10 ) with an air sucking path ( 13 ). 
     The pillar delivery method according to the sixth implementation allows the plurality of pillars ( 3 ) to be held with good stability by the holder ( 1 ) by sucking the air up through the air sucking path ( 13 ). 
     A seventh implementation of the pillar delivery method, which may be adopted in combination with any one of the first to sixth implementations, has the following additional features. In the pillar delivery method according to the seventh aspect, the holding step includes having the plurality of pillars ( 3 ), which have been punched out of the sheet ( 2 ), received in, and held by, a plurality of grooves ( 105 ) provided on the holder ( 1 ). 
     The pillar delivery method according to the seventh implementation allows the plurality of pillars ( 3 ), which have been punched out of the sheet ( 2 ) by laser cutting, to be held with good stability by the holder ( 1 ). 
     An eighth implementation of the pillar delivery method, which may be adopted in combination with the third implementation, has the following additional features. In the pillar delivery method according to the eighth implementation, the holding step includes having the plurality of pillars ( 3 ), which have been punched out of the sheet ( 2 ), received in a plurality of grooves ( 105 ) provided on the holder ( 1 ), suctioned onto an inner surface of the plurality of grooves ( 105 ), and thereby held by the holder ( 1 ). 
     The pillar delivery method according to the eighth implementation allows the plurality of pillars ( 3 ), which have been punched out of the sheet ( 2 ) by laser cutting, to be held with good stability by the holder ( 1 ). 
     A first implementation of a method for manufacturing a glass panel unit includes a pillar delivery step, an arrangement step, a bonding step, an evacuation step, and a sealing step. The pillar delivery step includes delivering the plurality of pillars ( 3 ) onto the substrate ( 91 ) by any one of the first through eighth implementations of the pillar delivery method. The arrangement step includes laying a counter substrate ( 92 ), including a glass panel ( 920 ), over the substrate ( 91 ). The bonding step includes bonding respective peripheral edges of the substrate ( 91 ) and the counter substrate ( 92 ) together to form an internal space (S 1 ) where the plurality of pillars ( 3 ) are located. The evacuation step includes evacuating the internal space (S 1 ). The sealing step includes sealing the internal space (S 1 ) while keeping the internal space (S) evacuated. 
     The method for manufacturing a glass panel unit according to the first implementation allows a glass panel unit, including a plurality of pillars ( 3 ) with significantly reduced burr, to be manufactured efficiently. 
     As can be seen from the foregoing description of embodiments and their variations, a first implementation of a pillar delivery apparatus ( 8 ) has the following configuration: 
     A first implementation of the pillar delivery apparatus ( 8 ) is an apparatus for delivering a plurality of pillars ( 3 ) onto a substrate ( 91 ), including a glass panel ( 910 ), to manufacture a glass panel unit. The pillar delivery apparatus ( 8 ) according to the first implementation includes a holder ( 1 ), a sheet ( 2 ) for use to form pillars, a laser cutter ( 4 ), and a mounter ( 5 ). The sheet ( 2 ) is to be set over the holder ( 1 ). The laser cutter ( 4 ) is used to punch out the plurality of pillars ( 3 ) of the sheet ( 2 ) by irradiating the sheet ( 2 ) with a laser beam. The mounter ( 5 ) is used to pick up some or all of the plurality of pillars ( 3 ) held by the holder ( 1 ) and mount the pillars ( 3 ) onto the substrate ( 91 ). 
     The pillar delivery apparatus ( 8 ) according to the first implementation allows a plurality of pillars ( 3 ) formed by laser cutting with significantly reduced burr to be efficiently delivered onto the substrate ( 91 ). 
     A second implementation of the pillar delivery apparatus ( 8 ), which may be adopted in combination with the first implementation, has the following additional features. The pillar delivery apparatus ( 8 ) according to the second implementation further includes a suctioning mechanism ( 11 ) to have the plurality of pillars ( 3 ) suctioned onto the holder ( 1 ). 
     The pillar delivery apparatus ( 8 ) according to the second implementation allows a plurality of pillars ( 3 ) punched out of the sheet ( 2 ) by laser cutting to be held with good stability by the holder ( 1 ). 
     A third implementation of the pillar delivery apparatus ( 8 ), which may be adopted in combination with the second implementation, has the following additional features. In the pillar delivery apparatus ( 8 ) according to the third implementation, the suctioning mechanism ( 11 ) includes a sucking device ( 112 ) to suck the air up through the holder ( 1 ). 
     The pillar delivery apparatus ( 8 ) according to the third implementation allows a plurality of pillars ( 3 ) punched out of the sheet ( 2 ) by laser cutting to be held with good stability by the holder ( 1 ) by sucking the air up. 
     A fourth implementation of the pillar delivery apparatus ( 8 ), which may be adopted in combination with the third implementation, has the following additional features. In the pillar delivery apparatus ( 8 ) according to the fourth implementation, the holder ( 1 ) includes a body ( 10 ) with porosity. 
     The pillar delivery apparatus ( 8 ) according to the fourth implementation allows the plurality of pillars ( 3 ) to be held with good stability by the holder ( 1 ) by sucking the air up through the body ( 10 ) with porosity. 
     A fifth implementation of the pillar delivery apparatus ( 8 ), which may be adopted in combination with the third implementation, has the following additional features. In the pillar delivery apparatus ( 8 ) according to the fifth implementation, the holder ( 1 ) includes a body ( 10 ) with an air sucking path ( 13 ). 
     The pillar delivery apparatus ( 8 ) according to the fifth implementation allows the plurality of pillars ( 3 ) to be held with good stability by the holder ( 1 ) by sucking the air up through the air sucking path ( 13 ). 
     A sixth implementation of the pillar delivery apparatus ( 8 ), which may be adopted in combination with any one of the first to fifth implementations, has the following additional features. In the pillar delivery apparatus ( 8 ) according to the sixth implementation, the holder ( 1 ) includes a plurality of grooves ( 105 ) to hold the plurality of pillars ( 3 ). 
     The pillar delivery apparatus ( 8 ) according to the sixth implementation allows a plurality of pillars ( 3 ), punched out of the sheet ( 2 ) by laser cutting, to be held with good stability by the holder ( 1 ). 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  Holder 
               10  Body 
               105  Groove 
               11  Suctioning Mechanism 
               112  Sucking Device 
               13  Air Sucking Path 
               2  Sheet 
               3  Pillar 
               4  Laser Cutter 
               5  Mounter 
               8  Pillar Delivery Apparatus 
               91  Substrate 
               910  Glass Panel 
               92  Substrate 
               920  Glass Panel 
             S 1  Internal Space