Patent Description:
Patent Literature <NUM> discloses a method for manufacturing a glass panel unit in which a vacuum space is created between a pair of glass panels. According to this manufacturing method, a first glass substrate and a second glass substrate (a pair of glass substrates) are arranged to face each other with a frame member (peripheral wall) interposed between them. Thereafter, the frame member is heated and melted, thereby hermetically bonding the first glass substrate and the second substrate together. At this time, the internal space surrounded with the first and second glass substrates and the frame member is partitioned by a partition into a first space and a second space. The first space is evacuated through the second space to turn into a vacuum space. Thereafter, the vacuum space is sealed hermetically to obtain an assembly. A glass panel unit is obtained by cutting out a part of this assembly.

In the glass panel unit of Patent Literature <NUM>, the first glass substrate and the second glass substrate are bonded together with the frame member. In this case, if at least one of the first and second glass substrates has warpage, then the gap distance between the first and second glass substrates may be different in a central region thereof from in a peripheral region thereof. Particularly when the gap distance between the first and second glass substrates is narrower in the central region thereof than in the peripheral region thereof, the presence of the partition could prevent the frame member (peripheral wall) from making contact with the respective peripheral portions of the first and second glass substrates. This could cause insufficient bonding between the first and second glass substrates.

<CIT> describes a production method of multiple panes including hermetically bonding, with a sealing member, peripheries of paired glass panels disposed facing each other at a predetermined distance to form a space to be hermetically enclosed between the glass panels; evacuating air from the space through an outlet to make the space be in a reduced pressure state; subsequently dividing the space by region forming members disposed inside the space to form partial regions which do not include the outlet; and subsequently cutting out the partial regions by cutting the pair of glass panels.

<CIT> describes a manufacturing method for glass panel unit enabling efficient manufacture of a glass panel unit with desired shape and dimensions. A first glass substrate and a second glass substrate which are placed to face each other with a seal member in-between are bonded to each other with the seal member. Subsequently, the first glass substrate, the seal member, and the second glass substrate are cut collectively along a cut plane passing through the seal member from one of the first glass substrate and the second glass substrate bonded to each other.

<CIT> describes a method and a device for applying an adhesive to surface of a platelike body held vertically.

The problem to overcome is to provide a method for manufacturing a glass panel unit, both of which contribute to increasing the production yield. This problem is solved by the method for manufacturing a glass panel unit according to independent claim <NUM>. Specific embodiments are defined in the dependent claims.

An example for better understanding the invention is a glass panel unit assembly including a pair of glass substrates arranged to face each other; a peripheral wall having a frame shape and disposed between the pair of glass substrates; a partition; an air passage; and an evacuation port. The partition partitions an internal space, surrounded with the pair of glass substrates and the peripheral wall, into a first space and a second space. The air passage connects the first space and the second space together. The evacuation port connects the second space to an external environment. The partition is lower in height than the peripheral wall.

<FIG> and <FIG> illustrate a glass panel unit assembly (hereinafter simply referred to as an "assembly") The assembly <NUM> is used to manufacture one or more glass panel units (e.g., the glass panel units 10A-<NUM> shown in <FIG> in this embodiment). An assembly <NUM> includes: a pair of glass substrates <NUM>, <NUM> arranged to face each other; a peripheral wall <NUM>; partitions 420a-420p; an air passage <NUM>; and an evacuation port <NUM>. The peripheral wall <NUM> has a frame shape and is disposed between the pair of glass substrates <NUM>, <NUM>. The partitions 420a-420p partition an internal space <NUM>, surrounded with the pair of glass substrates <NUM>, <NUM> and the peripheral wall <NUM>, into first spaces 510a-<NUM> and second spaces 520a, 520b. The air passage <NUM> (directly or indirectly) connects the first spaces 510a-<NUM> and the second spaces 520a, 520b together. The evacuation port <NUM> connects the second spaces 520a, 520b to an external environment. The partitions 420a-420p are lower in height than the peripheral wall <NUM> as shown in <FIG> and <FIG>.

In this assembly <NUM>, the partitions 420a-420p are located within an area surrounded with the peripheral wall <NUM> and are lower in height than the peripheral wall <NUM>. Thus, even if the gap between the pair of glass substrates <NUM>, <NUM> is narrower in the central region than in the peripheral region thereof due to the warpage of at least one of the glass substrates <NUM>, <NUM>, the partitions 420a-420p are less likely to come into contact with both of the pair of glass substrates <NUM>, <NUM>. This reduces the chances of the contact of the peripheral wall <NUM> with both of the pair of glass substrates <NUM>, <NUM> being interfered with by the partitions 420a-420p, thus reducing the chances of causing insufficient bonding between the pair of glass substrates <NUM>, <NUM>. This contributes to increasing the production yield.

Next, a glass panel unit assembly <NUM> will be described in detail. The assembly <NUM> is used to manufacture a plurality of (e.g., seven in this example) glass panel units <NUM> (10A-<NUM>) as shown in <FIG>.

The glass panel units <NUM> (10A-<NUM>) are vacuum insulated glazing units. The vacuum insulated glazing unit is a type of multi-pane glazing unit (or multi-pane glass panel unit) including at least one pair of glass panels and has a vacuum space between the pair of glass panels. Each of the glass panel units 10A-<NUM> includes a pair of glass panels (first and second glass panels) <NUM>, <NUM>, and a frame member <NUM> as shown in <FIG>. In addition, each of the glass panel units 10A-<NUM> further includes a space (vacuum space) <NUM> (50a-<NUM> (see <FIG>)) surrounded with the pair of glass panels <NUM>, <NUM> and the frame member <NUM>. Each of the glass panel units 10A-<NUM> further includes, within the vacuum space <NUM>, a gas adsorbent <NUM> and a plurality of pillars (spacers) <NUM>. As can be seen from <FIG>, the glass panel units 10A-<NUM> each have a quadrangular shape in a plan view, but not all the glass panel units 10A-<NUM> have the same dimensions or the same shape.

The pair of glass panels <NUM>, <NUM> have the same shape, and may be each formed in a rectangular flat plate shape. Examples of materials for the pair of glass panels <NUM>, <NUM> include soda lime glass, high strain point glass, chemically tempered glass, alkali-free glass, quartz glass, Neoceram, and thermally tempered glass. The surface of the pair of glass panels <NUM>, <NUM> may be covered with a coating. The coating may be a transparent infrared reflective film, for example. However, this is only an example and should not be construed as limiting. The coating does not have to be an infrared reflective film but may also be any other film with desired physical properties.

The frame member <NUM> is arranged between the pair of glass panels <NUM>, <NUM> to hermetically bond the pair of glass panels <NUM>, <NUM> together. This allows a space, surrounded with the pair of glass panels <NUM>, <NUM> and the frame member <NUM>, to be created. In addition, the space surrounded with the pair of glass panels <NUM>, <NUM> and the frame member <NUM> is a vacuum space <NUM>. The frame member <NUM> may be made of a hot glue as a sealant. In other words, the frame member <NUM> is a cured hot glue. The hot glue may be a glass frit, for example. The glass frit may be a low-melting glass frit, for example. Examples of the low-melting glass frits include a bismuth-based glass frit, a lead-based glass frit, and a vanadium-based glass frit. The frame member <NUM>, as well as the pair of glass panels <NUM>, <NUM>, has a polygonal shape (e.g., a quadrangular shape in this embodiment). The frame member <NUM> is formed along the respective outer peripheries of the pair of glass panels <NUM>, <NUM>. The hot glue does not have to be a glass frit but may also be a low-melting metal or a hot-melt adhesive, for example.

The gas adsorbent <NUM> is arranged in the vacuum space <NUM>. Specifically, the gas adsorbent <NUM> has an elongate flat-plate shape and is arranged on the glass panel <NUM>. The gas adsorbent <NUM> is used to adsorb an unnecessary gas (such as a residual gas). The unnecessary gas is a gas emitted from the hot glue forming the frame member <NUM> when the hot glue is heated, for example. The gas adsorbent <NUM> includes a getter. The getter is a material having the property of adsorbing molecules smaller in size than a predetermined one. The getter may be an evaporative getter, for example. The evaporative getter has the property of releasing adsorbed molecules when heated to a predetermined temperature (activation temperature) or more. This allows, even if the adsorption ability of the evaporative getter deteriorates, the evaporative getter to recover its adsorption ability by being heated to the activation temperature or more. The evaporative getter may be a zeolite or an ion-exchanged zeolite (such as a copper ion exchanged zeolite). The gas adsorbent <NUM> includes a powder of this getter. Specifically, the gas adsorbent <NUM> may be formed by applying a liquid including a powder of the getter (such as a dispersion liquid obtained by dispersing a powder of the getter in a liquid or a solution obtained by dissolving a powder of the getter in a liquid) and solidifying the liquid. This reduces the size of the gas adsorbent <NUM>, thus allowing the gas adsorbent <NUM> to be arranged even when the vacuum space <NUM> is narrow.

The plurality of pillars <NUM> are placed in the vacuum space <NUM>. The plurality of pillars <NUM> is used to maintain a predetermined gap between the pair of glass panels <NUM>, <NUM>. That is to say, the plurality of pillars <NUM> is used to maintain the gap distance between the pair of glass panels <NUM>, <NUM> at a desired value. Note that the dimensions, number, spacing, and arrangement pattern of the pillars <NUM> may be selected appropriately. Each of the pillars <NUM> has the shape of a circular column, of which the height is approximately equal to the predetermined gap. For example, the pillars <NUM> may have a diameter of <NUM> and a height of <NUM>. Optionally, the pillars <NUM> may also have any other desired shape such as a prismatic or spherical shape.

As shown in <FIG> and <FIG>, the assembly <NUM> includes: a pair of glass substrates (first and second glass substrates) <NUM>, <NUM> arranged to face each other; a peripheral wall <NUM>; partitions 420a-420p; a plurality of air passages <NUM>; and an evacuation port <NUM>. The assembly <NUM> further includes a plurality of gas adsorbents <NUM> and a plurality of pillars (spacers) <NUM>.

The first glass substrate <NUM> is a member that forms the basis of the first glass panel <NUM> and is made of the same material as the first glass panel <NUM>. The second glass substrate <NUM> is a member that forms the basis of the second glass panel <NUM> and is made of the same material as the second glass panel <NUM>. The first and second glass substrates <NUM>, <NUM> have the same shape and each have a polygonal plate shape (e.g., a rectangular plate shape in this embodiment). In this embodiment, the first glass substrate <NUM> has dimensions that are large enough to form the respective first glass panels <NUM> of the glass panel units 10A-<NUM>, and the second glass substrate <NUM> has dimensions that are large enough to form the respective second glass panels <NUM> of the glass panel units 10A-<NUM>.

The peripheral wall <NUM> is made of a sealant (first sealant). The first sealant includes a hot glue, for example. The hot glue may be a glass frit, for example. The glass frit may be a low-melting glass frit, for example. Examples of the low-melting glass frits include a bismuth-based glass frit, a lead-based glass frit, and a vanadium-based glass frit. The first sealant further includes a core material. The core material is used to define the height of the frame member <NUM>. The core material may be spherical glass beads, for example. The diameter of the glass beads may be selected according to the height of the frame member <NUM>. Such a core material is dispersed at a predetermined ratio in the hot glue. For example, glass beads with a diameter of <NUM> to <NUM> are included to account for <NUM> wt% to <NUM> wt% (<NUM>% to <NUM>% by volume) of the hot glue.

The peripheral wall <NUM> is located between the pair of glass substrates <NUM>, <NUM>. The peripheral wall <NUM> has a frame shape as shown in <FIG>. In particular, the peripheral wall <NUM> may have a rectangular frame shape. The peripheral wall <NUM> is formed along the respective outer peripheries of the first and second glass substrates <NUM>, <NUM>. The peripheral wall <NUM> has first to fourth sides 410a-410d. The first and second sides 410a, 410b extend along the width of the first and second glass substrates <NUM>, <NUM> (i.e., in the upward/downward direction in <FIG>). The third and fourth sides 410c, 410d extend along the length of the first and second glass substrates <NUM>, <NUM> (i.e., in the rightward/leftward direction in <FIG>). The peripheral wall <NUM> is provided to hermetically bond the first and second glass substrates <NUM>, <NUM> together. Thus, in the assembly <NUM>, an internal space <NUM> is formed to be surrounded with the peripheral wall <NUM>, the first glass substrate <NUM>, and the second glass substrate <NUM>.

Each of the plurality of partitions 420a-420p is made of a sealant (second sealant). The second sealant includes a hot glue, for example. The hot glue may be a glass frit, for example. The glass frit may be a low-melting glass frit, for example. Examples of the low-melting glass frits include a bismuth-based glass frit, a lead-based glass frit, and a vanadium-based glass frit. In this embodiment, the hot glue of the partitions 420a-420p is the same as that of the peripheral wall <NUM>. Therefore, the partitions 420a-420p and the peripheral wall <NUM> have the same softening point. In addition, the second sealant includes the same core material as the first sealant. In the second sealant, the core material is also dispersed at a predetermined ratio in the hot glue. For example, glass beads with a diameter of <NUM> to <NUM> are included to account for <NUM> wt% to <NUM> wt% (<NUM>% to <NUM>% by volume) of the hot glue.

The partitions 420a-420p partition the internal space <NUM> surrounded with the pair of glass substrates <NUM>, <NUM> and the peripheral wall <NUM> into first spaces 510a-<NUM> and second spaces 520a, 520b. In the assembly <NUM>, the first spaces 510a-<NUM> are spaces to be evacuated later (evacuation spaces) and the second spaces 520a, 520b are spaces for use to evacuate the first spaces <NUM>.

As shown in <FIG>, the partitions 420a-420p are located within the area surrounded with the peripheral wall <NUM>. Each of the partitions 420a-420p is lower in height than the peripheral wall <NUM>. Thus, as shown in <FIG>, the peripheral wall <NUM> comes into contact with both the first and second glass substrates <NUM>, <NUM> earlier than the partitions 420a-420p do. In the example illustrated in <FIG>, the partitions 420a-420p are provided on the second glass substrate <NUM>, and therefore, are spaced apart from the first glass substrate <NUM>. Thus, even if the gap between the pair of glass substrates <NUM>, <NUM> is narrower in the central region than in the peripheral region thereof due to the warpage of at least one of the first and second glass substrates <NUM>, <NUM>, the partitions 420a-420p are less likely to come into contact with both of the pair of glass substrates <NUM>, <NUM>. This reduces the chances of the contact of the peripheral wall <NUM> with both of the pair of glass substrates <NUM>, <NUM> being interfered with by the partitions 420a-420p, thus reducing the chances of causing insufficient bonding between the pair of glass substrates <NUM>, <NUM>. This contributes to increasing the production yield.

More specifically, the partitions 420a, 420b, 420c are elongate partitions extending along the width of the pair of glass substrates <NUM>, <NUM>, (i.e., the upward/downward direction in <FIG>) and are arranged in line so as to be spaced apart from each other along the width. The partitions 420a, 420b, 420c are located beside a first end (i.e., the right end in <FIG>) along the length of the pair of glass substrates <NUM>, <NUM> (i.e., the rightward/leftward direction in <FIG>) and are arranged to be spaced from the first side 410a of the peripheral wall <NUM>.

The partitions 420d, 420e, 420f are elongate partitions extending along the width of the pair of glass substrates <NUM>, <NUM>, and are arranged in line to be spaced apart from each other along the width. The partitions 420d, 420e, 420f are located closer to a second end (i.e., the left end in <FIG>) along the length of the pair of glass substrates <NUM>, <NUM> than the partitions 420a, 420b, 420c are. In addition, the partitions 420d, 420e, 420f face the partitions 420a, 420b, 420c, respectively, along the length of the pair of glass substrates <NUM>, <NUM>.

The partitions <NUM>, <NUM> are elongate partitions extending along the width of the pair of glass substrates <NUM>, <NUM>, and are arranged so as to be spaced apart from each other along the length of the pair of glass substrates <NUM>, <NUM>. The partitions <NUM>, <NUM> are located closer to the second end (i.e., the left end in <FIG>) along the length of the pair of glass substrates <NUM>, <NUM> than the partition 420e is.

The partitions 420i, 420j, <NUM>, <NUM> are elongate partitions extending along the length of the pair of glass substrates <NUM>, <NUM>, and are arranged in line so as to be spaced apart from each other along the length. In particular, the partition 420i is located between a first end (i.e., the upper end in <FIG>) of the partition <NUM> and the second side 410b of the peripheral wall <NUM>. The partition 420j is located between respective first ends (i.e., the upper ends in <FIG>) of the partitions <NUM>, <NUM>. The partition <NUM> has a first end (i.e., the right end in <FIG>) located between the partitions 420d, 420e, and a second end (i.e., the left end in <FIG>) facing the first end (i.e., the upper end in <FIG>) of the partition <NUM>. The partition <NUM> has a first end (i.e., the right end in <FIG>) located between the partitions 420a, 420b and a second end (i.e., the left end in <FIG>) located between the partitions 420d, 420e.

The partitions <NUM>, 420n, 420o are elongate partitions extending along the length of the pair of glass substrates <NUM>, <NUM>, and are arranged in line to be spaced apart from each other along the length. In addition, the partitions <NUM>, 420n, 420o face the partitions 420i, 420j, <NUM>, respectively, along the width of the pair of glass substrates <NUM>, <NUM>. In particular, the partition <NUM> is located between a second end (i.e., the lower end in <FIG>) of the partition <NUM> and the second side 410b of the peripheral wall <NUM>. The partition 420n is located between respective second ends (i.e., the lower ends in <FIG>) of the partitions <NUM>, <NUM>. The partition 420o has a first end (i.e., the right end in <FIG>) facing an end, located closer to the fourth side 410d of the peripheral wall <NUM>, of the partition 420e, and a second end (i.e., the left end in <FIG>) facing the second end (i.e., the lower end in <FIG>) of the partition <NUM>.

The partition 420p is an elongate partition extending along the length of the pair of glass substrates <NUM>, <NUM>. In particular, the partition 420p has a first end (i.e., the right end in <FIG>) located between the partitions 420b, 420c and a second end (i.e., the left end in <FIG>) located between the partitions 420e, 420f.

In the assembly <NUM>, the first space 510a is a space surrounded with the second and third sides 410b, 410c of the peripheral wall <NUM> and the partitions 420d, 420i, 420j, <NUM>, <NUM>, <NUM>. The first space 510b is a space surrounded with the second side 410b of the peripheral wall <NUM> and the partitions <NUM>, 420i, <NUM>. The first space 510c is a space surrounded with the partitions <NUM>, <NUM>, 420j, 420n. The first space 510d is a space surrounded with the partitions 420e, <NUM>, <NUM>, 420o. The first space 510e is a space surrounded with the second and fourth sides 410b, 410d of the peripheral wall <NUM> and the partitions 420e, 420f, <NUM>, <NUM>, <NUM>, 420n, 420o, 420p. The first space 510f is a space surrounded with the third side 410c of the peripheral wall <NUM> and the partitions 420a, 420d, <NUM>. The first space <NUM> is a space surrounded with the partitions 420b, 420e, <NUM>, 420p. The second space 520a is a space surrounded with the first, third and fourth sides 410a, 410c, 410d of the peripheral wall <NUM> and the partitions 420a, 420b, 420c, <NUM>, 420p. The second space 520b is a space surrounded with the fourth side 410d of the peripheral wall <NUM> and the partitions 420c, 420f, 420p.

The gas adsorbent <NUM> is arranged in each of the first spaces 510a-<NUM> as shown in <FIG>. On the other hand, the plurality of pillars <NUM> are placed over the entire internal space <NUM> (i.e., in each of the first spaces 510a-<NUM> and the second spaces 520a, 520b) as shown in <FIG>.

The plurality of air passages <NUM> is used to evacuate the first spaces (evacuation spaces) 510a-<NUM> through the evacuation port <NUM>. In other words, via the plurality of air passages <NUM>, the first spaces 510a-<NUM> are connected (either directly or indirectly) to the second space 520a, 520b. In this embodiment, the partitions 420a-420p are arranged out of contact with each other. The respective gaps left between the partitions 420a-420p constitute the air passages <NUM>. The respective air passages <NUM> are closed by melting and deforming the partitions 420a-420p once. This allows not only at least the first spaces 510a-<NUM> to be (hermetically) separated from each other but also the first spaces 510a-<NUM> to be (hermetically) separated from the second spaces 520a, 520b (see <FIG>).

The evacuation port <NUM> connects the second spaces 520a, 520b to the external environment. In particular, the evacuation port <NUM> is a port connecting the second space 520a to the external environment. The evacuation port <NUM> is used to evacuate the first spaces 510a-<NUM> through the second spaces 520a, 520b and the air passages <NUM>. Thus, the air passages <NUM>, the second spaces 520a, 520b, and the evacuation port <NUM> together form an evacuation path for evacuating the first spaces 510a-<NUM>. The evacuation port <NUM> is provided through the second glass substrate <NUM> to connect the second space 520a to the external environment. Specifically, the evacuation port <NUM> is provided at a corner of the second glass substrate <NUM>.

The second space 520a is a ventilation space connected directly to the evacuation port <NUM>. The second space 520b is not directly connected to the evacuation port <NUM> but constitutes a coupling space that connects the first space 510e to the second space 520a. The plurality of air passages <NUM> includes a plurality of air passages (two first air passages <NUM>, <NUM>) connecting the first space (evacuation space) 510e to the second space (coupling space) 520b as shown in <FIG>. The plurality of air passages <NUM> further includes a plurality of air passages (two second air passages <NUM>, <NUM>) connecting the second space (ventilation space) 520a to the second space (coupling space) 520b. The plurality of air passages <NUM> further includes a plurality of air passages <NUM> connecting the first spaces 510f, <NUM> to the second space 520a and a plurality of air passages <NUM> connecting the first spaces 510a-<NUM> together.

More specifically, the first air passage <NUM> is an air passage between a first end (e.g., the upper end in <FIG>) of the partition 420f and a second end (e.g., the left end in <FIG>) of the partition 420p. The first air passage <NUM> is an air passage between a second end (e.g., the lower end in <FIG>) of the partition 420f and the fourth side 410d of the peripheral wall <NUM>. On the other hand, the second air passage <NUM> is an air passage between a first end (e.g., the upper end in <FIG>) of the partition 420c and a first end (e.g., the right end in <FIG>) of the partition 420p. The second air passage <NUM> is an air passage between a second end (e.g., the lower end in <FIG>) of the partition 420c and the fourth side 410d of the peripheral wall <NUM>. In this case, the second air passage <NUM> has a larger dimension than any of the first air passages <NUM>, <NUM>. That is to say, one or more second air passages <NUM>, <NUM> include a particular air passage <NUM> having a larger dimension than one or more first air passages <NUM>, <NUM>. This allows the coupling space 520b to be used as a part of the evacuation path when the evacuation space 510e is evacuated via the evacuation port <NUM>. This allows evacuation to be done efficiently. Among other things, this reduces the chances of, when the air passages <NUM> are closed by deforming the partitions 420a-420p in a second melting step (sealing step) to be described later, the second air passages <NUM>, <NUM> being both closed before the first air passages <NUM>, <NUM> are all closed. Thus, this reduces the chances of the evacuation space 510e being separated from the ventilation space 520a before the evacuation space 510e is evacuated sufficiently. This contributes to increasing the production yield.

Next, a method for manufacturing the glass panel units <NUM> (10A-<NUM>) using the assembly <NUM> will be described with reference to <FIG>. This method for manufacturing the glass panel units <NUM> includes preparatory steps and a removing step.

The preparatory steps are steps of providing the work in progress <NUM> of glass panel units (hereinafter simply referred to as the "work in progress <NUM>") shown in <FIG> and <FIG>. The work in progress <NUM> is formed out of the glass panel unit assembly <NUM>.

The work in progress <NUM> includes: the pair of glass substrates (first and second glass substrates) <NUM>, <NUM>; a peripheral wall <NUM>; and boundary walls 42a-<NUM> as shown in <FIG> and <FIG>. In addition, the work in progress <NUM> further has vacuum spaces 50a-<NUM> and second spaces 520a, 520b. Besides, the work in progress <NUM> further includes gas adsorbents <NUM> and a plurality of pillars (spacers) <NUM> in the respective vacuum spaces 50a-<NUM>. The work in progress <NUM> further has an evacuation port <NUM>.

The peripheral wall <NUM> is provided between the pair of glass substrates <NUM>, <NUM> to hermetically bond the pair of glass substrates <NUM>, <NUM> together. The peripheral wall <NUM> is formed by once melting, and then solidifying again, the peripheral wall <NUM> of the assembly <NUM>. Just like the peripheral wall <NUM> of the assembly <NUM>, the peripheral wall <NUM> of the work in progress <NUM> also has a frame shape. In particular, the peripheral wall <NUM> has first to fourth sides 41a, 41b, 41c, 41d. The first and second sides 41a, 41b extend along the width of the first and second glass substrates <NUM>, <NUM> (i.e., in the upward/downward direction in <FIG>). The third and fourth sides 41c, 41d extend along the length of the first and second glass substrates <NUM>, <NUM> (i.e., the rightward/leftward direction in <FIG>).

The boundary walls 42a-<NUM> (spatially) separate the vacuum spaces 50a-<NUM> and the second spaces 520a, 520b from each other. The boundary walls 42a-<NUM> are formed out of the partitions 420a-420p. More specifically, the boundary wall 42a linearly extends along the width of the pair of glass substrates <NUM>, <NUM> to couple together the third and fourth sides 41c, 41d of the peripheral wall <NUM>.

The boundary wall 42a is formed by deforming the partitions 420a, 420b, 420c, <NUM>, 420p. The boundary wall 42b linearly extends along the width of the pair of glass substrates <NUM>, <NUM> to couple together the third and fourth sides 41c, 41d of the peripheral wall <NUM>. The boundary wall 42b is located between the boundary wall 42a and the second side 41b of the peripheral wall <NUM>. The boundary wall 42b is formed by deforming the partitions 420d, 420e, 420f, <NUM>, <NUM>, 420p. The boundary wall 42c linearly extends along the length of the pair of glass substrates <NUM>, <NUM> to couple together the second side 41b of the peripheral wall <NUM> and the boundary wall 42b. The boundary wall 42c is formed by deforming the partitions 420i, 420j, <NUM>, <NUM>, <NUM>. The boundary wall 42d linearly extends along the length of the pair of glass substrates <NUM>, <NUM> to couple together the second side 41b of the peripheral wall <NUM> and the boundary wall 42b. The boundary wall 42d is located between the boundary wall 42c and the fourth side 41d of the peripheral wall <NUM>. The boundary wall 42d is formed by deforming the partitions <NUM>, 420n, 420o, <NUM>, <NUM>. The boundary wall 42e, 42f linearly extend along the width of the pair of glass substrates <NUM>, <NUM> to couple together the boundary walls 42c, 42d. The boundary walls 42e, 42f are formed by deforming the partitions <NUM>, <NUM>, respectively. The boundary wall <NUM>, <NUM> linearly extend along the length of the pair of glass substrates <NUM>, <NUM> to couple together the boundary walls 42a, 42b. The boundary walls <NUM>, <NUM> are formed by deforming the partitions <NUM>, 420p, respectively.

The vacuum spaces 50a-<NUM> are formed by evacuating the first spaces 510a-<NUM>, respectively, through the second spaces 520a, 520b and the evacuation port <NUM>. In other words, the vacuum spaces 50a-<NUM> are the first spaces 510a-<NUM> having a degree of vacuum equal to or less than a predetermined value. The predetermined value may be <NUM> Pa, for example. The vacuum spaces 50a-<NUM> are perfectly sealed hermetically by the first glass substrate <NUM>, the second glass substrate <NUM>, the peripheral wall <NUM>, and the boundary walls 42a-<NUM>, and therefore, are separated from the second spaces 520a, 520b and the evacuation port <NUM>.

In the work in progress <NUM>, the vacuum space 50a (first space 510a) is a space surrounded with the second and third sides 41b, 41c of the peripheral wall <NUM> and the boundary walls 42b, 42c. The vacuum space 50b (first space 510b) is a space surrounded with the second side 41b of the peripheral wall <NUM> and the boundary walls 42c, 42d, 42e. The vacuum space 50c (first space 510c) is a space surrounded with the boundary walls 42c, 42d, 42e, 42f. The vacuum space 50d (first space 510d) is a space surrounded with the boundary walls 42b, 42c, 42d, 42f. The vacuum space 50e (first space 510e) is a space surrounded with the second and fourth sides 41b, 41d of the peripheral wall <NUM> and the boundary walls 42b, 42d. The vacuum space 50f (first space 510f) is a space surrounded with the third side 41c of the peripheral wall <NUM> and the boundary walls 42a, 42b, <NUM>. The vacuum space <NUM> (first space <NUM>) is a space surrounded with the boundary walls 42a, 42b, <NUM>, <NUM>.

As can be seen, the peripheral wall <NUM> and the boundary walls 42a-<NUM> include, as their integral parts, a plurality of frame members <NUM> surrounding the vacuum spaces 50a-<NUM>. That is to say, portions surrounding the respective vacuum spaces 50a-<NUM> of the peripheral wall <NUM> and the boundary walls 42a-<NUM> form the frame members <NUM>.

The preparatory steps are steps of providing the work in progress <NUM> described above. The preparatory steps include an assembling step, a first melting step, an evacuation step, and a second melting step.

The assembling step is the step of providing the assembly <NUM>. That is to say, the assembling step is the step of forming the first glass substrate <NUM>, the second glass substrate <NUM>, the peripheral wall <NUM>, the partitions 420a-420p, the internal space <NUM>, the air passages <NUM>, the evacuation port <NUM>, the plurality of gas adsorbents <NUM>, and the plurality of pillars <NUM> to obtain the assembly <NUM>. The assembling step includes first to sixth steps. Optionally, the order in which the second to fifth steps are performed may be changed as appropriate.

The first step is the step of forming the first glass substrate <NUM> and the second glass substrate <NUM> (i.e., a substrate forming step). For example, the first step includes making the first glass substrate <NUM> and the second glass substrate <NUM>. If necessary, the first step may further include cleaning the first glass substrate <NUM> and the second glass substrate <NUM>.

The second step is the step of forming the evacuation port <NUM>. The second step includes providing the evacuation port <NUM> through the second glass substrate <NUM> as shown in <FIG>. If necessary, the second step includes cleaning the second glass substrate <NUM>.

The third step is the step of arranging the peripheral wall <NUM> and the partitions 420a-420p (sealant arrangement step). The third step includes a peripheral wall forming step and a partition forming step.

The peripheral wall forming step is the step of forming the peripheral wall <NUM>. More specifically, the peripheral wall forming step is the step of forming the peripheral wall <NUM> by applying a material for the peripheral wall <NUM> (first sealant) <NUM> through a dispenser <NUM> onto one of the pair of glass substrates <NUM>, <NUM> (e.g., the second glass substrate <NUM> in this example) as shown in <FIG>. In the peripheral wall forming step, when the material <NUM> for the peripheral wall <NUM> is applied onto the second glass substrate <NUM>, the material <NUM> for the peripheral wall <NUM> discharged through a nozzle <NUM> of the dispenser <NUM> is not to be pressed by the nozzle <NUM> as shown in <FIG>. Then, the dispenser <NUM> is moved along the peripheral edges of the second glass substrate <NUM> (e.g., as indicated by the arrow <NUM> shown in <FIG>) with the material <NUM> discharged through the nozzle <NUM>. Thereafter, the material <NUM> is allowed to dry to form the peripheral wall <NUM>. In this manner, a peripheral wall <NUM>, of which the first to fourth sides 410a-410d have a height H1 and a width W1, is obtained as shown in <FIG>. The height of the peripheral wall <NUM> defines the dimension of the peripheral wall <NUM> in the direction in which the pair of glass substrates <NUM>, <NUM> face each other. In this embodiment, the height of the peripheral wall <NUM> is the height H1 of the first to fourth sides 410a-410d. The height H1 and the width W1 may be adjusted according to the traveling velocity of the dispenser <NUM> and the rate of discharging the material <NUM>, for example.

The partition forming step is the step of forming the partitions 420a-420p. In the following description of the partition forming step, when there is no need to distinguish the partitions 420a-420p from each other, the partitions 420a-420p will be hereinafter collectively referred to "partitions <NUM>. " This partition forming step is the step of forming the partitions <NUM> by applying a material (second sealant) <NUM> for the partitions <NUM> through a dispenser <NUM> onto one of the pair of glass substrates <NUM>, <NUM> (e.g., the second glass substrate <NUM>) as shown in <FIG>. In this partition forming step, when the material <NUM> for the partitions <NUM> is applied onto the second glass substrate <NUM>, the material <NUM> for the partitions <NUM> discharged through a nozzle <NUM> of the dispenser <NUM> is pressed by the nozzle <NUM> as shown in <FIG>. This is done to adjust the height of the partitions <NUM>. This allows the partitions <NUM> obtained to have a height H2 which is smaller than the height H1 of the peripheral wall <NUM> as shown in <FIG>. The height of the partitions <NUM> is the dimension of the partitions <NUM> in the direction in which the pair of glass substrates <NUM>, <NUM> face each other. The width W2 of the partitions <NUM> may be adjusted according to the traveling velocity of the dispenser <NUM> and the discharge rate of the material <NUM>, for example. However, the range in which the width W2 is adjustable by the traveling velocity of the dispenser <NUM>. the discharge rate of the material <NUM>, or any other parameter has a limit. Thus, in this embodiment, to make the width W2 of the partitions <NUM> greater than the width of the peripheral wall <NUM> (i.e., the width W1 of the first to fourth sides 410a-410d thereof), the materials <NUM> for the partitions <NUM> are applied adjacent to one another in a direction defining the width of the partitions <NUM> an increased number of times. That is to say, the number of times of applying the material <NUM> so that the materials <NUM> are adjacent to one another in the direction defining the width of the partitions <NUM> is greater than the number of times of applying the material <NUM> so that the materials <NUM> are adjacent to one another in the direction defining the width of the peripheral wall <NUM> (i.e., the width of the respective sides 410a-410d thereof). In other words, when the partitions <NUM> are formed, the number of application lines is increased compared to when the peripheral wall <NUM> is formed.

In this embodiment, two application lines <NUM>, <NUM> are formed by applying the material <NUM> for the partitions <NUM> twice in the direction defining the length of the partitions <NUM> so that the materials <NUM> are adjacent to one another in the direction defining the width of the partitions <NUM> as shown in <FIG>. Specifically, the dispenser <NUM> is moved along the sides of quadrangles as indicated by the arrows 422a-422p shown in <FIG> with the material <NUM> discharged through the nozzle <NUM>. Note that the arrows 422a-422p correspond to the partitions 420a-420p, respectively. In this case, the interval D1 between the two adjacent application lines <NUM>, <NUM> is set such that the respective surfaces of the two adjacent application lines <NUM>, <NUM> are connected together to be level with each other (i.e., located on the same plane). This eliminates a recess from between the respective surfaces of the adjacent application lines <NUM>, <NUM>. This allows a partition <NUM> with a flat surface to be obtained as shown in <FIG>. As used herein, "applying the material adjacently" means forming application lines adjacent to each other. Optionally, the application lines <NUM>, <NUM> may be adjacent to each other to partially overlap with each other as shown in <FIG>.

Thereafter, the material <NUM> is allowed to dry, thereby forming the partitions <NUM>. In this manner, partitions <NUM> (420a-420p) with the height H2 and the width W2 are obtained as shown in <FIG>. As can be seen, in the partition forming step, the material <NUM> for the partitions <NUM> discharged through the nozzle <NUM> of the dispenser <NUM> is pressed with the nozzle <NUM> of the dispenser <NUM>. This makes the partitions <NUM> lower in height than the peripheral wall <NUM>. In addition, in the partition forming step, the number of times of applying the material <NUM> so that the materials <NUM> are adjacent to one another in the direction defining the width of the partitions <NUM> is larger than the number of times of applying the material <NUM> so that the materials <NUM> are adjacent to one another in the direction defining the width of the respective sides 410a-410d of the peripheral wall <NUM> as described above. This allows the partitions <NUM> to have a broader width than the peripheral wall <NUM>.

The fourth step is the step of forming pillars <NUM> (pillar forming step). The fourth step includes forming a plurality of pillars <NUM> in advance and placing, using a chip mounter or any other tool, the plurality of pillars <NUM> at predetermined positions on the second glass substrate <NUM>. In this embodiment, the pillars <NUM> are lower in height than the partitions 420a-420p. Alternatively, the plurality of pillars <NUM> may also be formed by a combination of photolithography and etching techniques. In that case, the plurality of pillars <NUM> may be made of a photocurable material, for example. Still alternatively, the plurality of pillars <NUM> may also be formed by a known thin film forming technique.

The fifth step is the step of forming the gas adsorbents <NUM> (gas adsorbent forming step). The fifth step includes forming the gas adsorbents <NUM> by applying, using a dispenser, for example, a solution in which a powder of a getter is dispersed onto predetermined positions on the second glass substrate <NUM> and drying the solution.

By performing these first to fifth steps, the peripheral wall <NUM>, the partitions 420a-420p, the air passages <NUM>, the evacuation port <NUM>, the plurality of gas adsorbents <NUM>, and the plurality of pillars <NUM> are formed on the second glass substrate <NUM> as shown in <FIG>.

The sixth step is the step of arranging the first glass substrate <NUM> and the second glass substrate <NUM> (arrangement step). In the sixth step, the first glass substrate <NUM> and the second glass substrate <NUM> are arranged to be parallel to each other and face each other as shown in <FIG>.

The assembly <NUM> is obtained by performing this assembling step. After the assembling step has been performed, the first melting step (bonding step), the evacuation step, and the second melting step (sealing step) are carried out.

The first melting step is the step of melting the peripheral wall <NUM> once to hermetically bond the pair of glass substrates <NUM>, <NUM> together with the peripheral wall <NUM>. Specifically, the first glass substrate <NUM> and the second glass substrate <NUM> are loaded into a melting furnace and heated at a first melting temperature for a predetermined amount of time (first melting time). The first melting temperature and the first melting time are set such that the first glass substrate <NUM> and the second glass substrate <NUM> are hermetically bonded together with the peripheral wall <NUM> but that the air passages <NUM> are not closed with the partitions 420a-420p. That is to say, the lower limit of the first melting temperature is the softening point of the peripheral wall <NUM> but the upper limit of the first melting temperature is set such that the air passages <NUM> are not closed with the partitions 420a-420p. For example, if the softening point of the peripheral wall <NUM> and the partitions 420a-420p is <NUM>, the first melting temperature is set at <NUM>. The first melting time may be <NUM> minutes, for example. Also, in this first melting step, the peripheral wall <NUM> softens too much to support the first glass substrate <NUM> by itself anymore, and therefore, the first glass substrate <NUM> is supported by the partitions 420a-420p instead.

The evacuation step is the step of evacuating the first spaces (evacuation spaces) 510a-<NUM> through the air passages <NUM>, the second spaces (ventilation space and coupling space) 520a, 520b, and the evacuation port <NUM> and thereby turning the first spaces 510a-<NUM> into vacuum spaces <NUM> (50a-<NUM>). In other words, the vacuum spaces 50a-<NUM> are the first spaces 510a-<NUM> in vacuum condition. The evacuation may be carried out using a vacuum pump, for example. The vacuum pump may be connected to the assembly <NUM> via an evacuation pipe <NUM> and a sealing head <NUM> as shown in <FIG>. The evacuation pipe <NUM> may be bonded to the second glass substrate <NUM> such that the inside of the evacuation pipe <NUM> and the evacuation port <NUM> communicate with each other, for example. Then, the sealing head <NUM> is attached to the evacuation pipe <NUM>, thereby connecting a suction port of the vacuum pump to the evacuation port <NUM>. The first melting step, the evacuation step, and the second melting step are performed with the assembly <NUM> kept loaded in the melting furnace. Therefore, the evacuation pipe <NUM> is bonded to the second glass substrate <NUM> at least before the first melting step.

The evacuation step includes evacuating the first spaces 510a-<NUM> at a temperature equal to or higher than an evacuation temperature for a predetermined amount of time (evacuation time) via the air passages <NUM>, the second spaces 520a, 520b, and the evacuation port <NUM> before the second melting step is started. The evacuation temperature is set at a temperature higher than the activation temperature (e.g., <NUM>) of the getter of the gas adsorbents <NUM> but lower than the softening point (e.g., <NUM>) of the partitions 420a-420p. The evacuation temperature may be <NUM>, for example. This prevents the partitions 420a-420p from being deformed. In addition, this causes the getter of the gas adsorbents <NUM> to be activated and also causes the molecules (gas) adsorbed onto the getter to be released from the getter. Then, the molecules (i.e., the gas) released from the getter are exhausted through the first spaces 510a-<NUM>, the air passages <NUM>, the second spaces 520a, 520b, and the evacuation port <NUM>. Thus, this evacuation step allows the gas adsorbents <NUM> to recover their adsorption ability. The evacuation time is set to create vacuum spaces 50a-<NUM> with a predetermined degree of vacuum (e.g., a degree of vacuum of <NUM> Pa or less). The evacuation time may be set at <NUM> minutes, for example.

The second melting step is the step of closing the air passages <NUM> by deforming the partitions 420a-420p to form the boundary walls 42a-<NUM> and thereby obtain the work in progress <NUM>. That is to say, the second melting step includes closing the air passages <NUM> to form a plurality of frame members <NUM> surrounding the vacuum spaces 50a-<NUM>. As a result, as shown in <FIG>, <FIG>, and <FIG>, boundary walls 42a-<NUM> are formed which hermetically separate the internal space <NUM> into the first spaces 510a-<NUM> (vacuum spaces 50a-<NUM>) and the second spaces 520a, 520b. In other words, the second melting step is the step of forming the boundary walls 42a-<NUM> that hermetically separate the internal space <NUM> into the first spaces 510a-<NUM> and the second spaces 520a, 520b by deforming the partitions 420a-420p to close the air passages <NUM>. Note that in the second melting step, the partitions 420a-420p soften too much to support the first glass substrate <NUM> by themselves anymore, and therefore, the first glass substrate <NUM> is supported by the pillars <NUM> instead.

More specifically, melting the partitions 420a-420p once at a predetermined temperature (second melting temperature) equal to or higher than the softening point of the partitions 420a-420p causes the partitions 420a-420p to be deformed. Specifically, the first glass substrate <NUM> and the second glass substrate <NUM> are heated in the melting furnace at a second melting temperature for a predetermined amount of time (second melting time). The second melting temperature and the second melting time are set such that the partitions 420a-420p are softened to close the air passages <NUM>. The lower limit of the second melting temperature is the softening point (e.g., <NUM>) of the partitions 420a-420p. The second melting temperature may be set at <NUM>, for example. Also, the second melting time may be <NUM> minutes, for example.

In addition, in the second melting step, the internal space <NUM> continues to be evacuated. That is to say, the second melting step includes forming the boundary walls 42a-<NUM> that close the air passages <NUM> by deforming the partitions 420a-420p at the second melting temperature while evacuating the first spaces 510a-<NUM> via the air passages <NUM>, the second spaces 520a, 520b, and the evacuation port <NUM>. This further reduces the chances of the degree of vacuum in the vacuum spaces 50a-<NUM> decreasing during the second melting step. Nevertheless, in the second melting step, the internal space <NUM> does not have to be evacuated continuously. Optionally, the second melting step may also be the step of closing all of the plurality of air passages <NUM> but at least the second air passages <NUM>, <NUM> by deforming the partitions 420a-420p. That is to say, the second air passages <NUM>, <NUM> do not have to be closed. Optionally, however, the second air passages <NUM>, <NUM> may also be closed along with the other air passages <NUM>.

By performing these preparatory steps, the work in progress <NUM> shown in <FIG>, <FIG>, and <FIG> is obtained. In the work in progress <NUM>, the peripheral wall <NUM> and the partitions 420a-420p are once melted through the first melting step and the second melting step. Thus, the gap between the pair of glass substrates <NUM>, <NUM> is defined by the pillars <NUM>, not the peripheral wall <NUM>. That is to say, while being melted, the peripheral wall <NUM> is compressed between the first and second glass substrates <NUM>, <NUM>, thus forming a peripheral wall <NUM> which has a smaller height and a broader width than the peripheral wall <NUM>. That is to say, the peripheral wall <NUM> is the peripheral wall <NUM> that has been deformed through the sealing step (second melting step). The respective sides 41a-41d of this peripheral wall <NUM> have a smaller height and a broader width than the respective sides 410a-410d of the peripheral wall <NUM>. In the same way, the partitions 420a-420p being melted are also compressed between the first and second glass substrates <NUM>, <NUM>, thereby forming boundary walls 42a-<NUM>. That is to say, the boundary walls <NUM> (42a-<NUM>) are partitions <NUM> (420a-420p) that have been deformed through the sealing step (second melting step). These boundary walls 42a-<NUM> have a smaller height and a broader width than the partitions 420a-420p. In this embodiment, the height H1 and width W1 of the respective sides 410a-410d of the peripheral wall <NUM> and the height H2 and width W2 of the partitions 420a-420p are selected such that the width of the boundary walls 42a-<NUM> is double the width of the respective sides 41a-41d of the peripheral wall <NUM>. That is to say, the partitions 420a-420p are formed such that the boundary walls 42a-<NUM> will have a broader width than the peripheral wall <NUM> that has gone through the sealing step (i.e., the peripheral wall <NUM>). Although the partitions 420a-420p and the peripheral wall <NUM> have different heights, the same core material is dispersed in the first sealant and the second sealant. Thus, the peripheral wall <NUM> and the boundary walls 42a-<NUM> to be formed out of the peripheral wall <NUM> and the partitions 420a-420p, respectively, will have the same height. This allows the frame members <NUM> to have a uniform height.

The removing step is performed after the preparatory steps have been performed. The removing step is the step of obtaining glass panel units 10A-<NUM> out of the work in progress <NUM>. The removing step is the step of obtaining glass panel units 10A-<NUM> as parts including the first spaces (evacuation spaces) 510a-<NUM>, respectively, by removing a part 11A including the second space (ventilation space) 520a and a part 11B including the second space (coupling space) 520b. That is to say, the removing step includes cutting off the work in progress <NUM> into the glass panel units 10A-<NUM>. In the work in progress <NUM>, the glass panel units 10A-<NUM> form integral parts thereof. Thus, the glass panel units 10A-<NUM> are separated from each other by cutting off the work in progress <NUM>.

For example, as shown in <FIG>, the work in progress <NUM> (in particular, the glass substrates <NUM>, <NUM>) is cut off along cutting lines <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> aligned with the boundary walls 42a-<NUM>, respectively. Note that the cutting lines <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> pass through the respective centerlines of the boundary walls 42a-<NUM>. That is to say, each of the boundary walls 42a-<NUM> is divided into two along the width thereof. In this embodiment, the boundary walls 42a-<NUM> are formed out of the partitions 420a-420p. The partitions 420a-420p have a broader width than the respective sides 410a-410d of the peripheral wall <NUM>. Thus, the boundary walls 42a-<NUM> also have a broader width than the respective sides 41a-41d of the peripheral wall <NUM>. This facilitates the work of cutting off the work in progress <NUM> along the boundary walls 42a-<NUM>. In particular, this reduces the chances of the boundary walls 42a-<NUM> being damaged while being cut off to connect the first spaces 510a-<NUM> to the external environment unintentionally and cause a decrease in the degree of vacuum. This contributes to increasing the production yield. In addition, the width of the boundary walls 42a-<NUM> is double the width of the respective sides 41a-41d of the peripheral wall <NUM>. Thus, even if the frame member <NUM> includes a part of the peripheral wall <NUM>, the respective sides of the frame member <NUM> still have an equal width. This increases the strength of the frame member <NUM> as a whole.

Furthermore, in this embodiment, the plurality of spacers <NUM> are dispersed over the entire internal space <NUM> (i.e., in each of the first spaces 510a-<NUM> and the second spaces 520a, 520b). This allows the stress applied to the pair of glass substrates <NUM>, <NUM> while the work in progress <NUM> is being cut off to be distributed uniformly by the plurality of spacers, thus reducing the chances of the pair of glass substrates <NUM>, <NUM> being damaged or causing cutting failures.

To cut off the work in progress <NUM>, a cutter wheel <NUM> may be used as shown in <FIG> illustrates an example in which the work in progress <NUM> is cut off along a cutting line <NUM>. When the work in progress <NUM> is cut off with the cutter wheel <NUM>, rib marks <NUM> are observed on the cut plane. In <FIG>, the work in progress <NUM> is cut off from over the first glass substrate <NUM>. Thus, the rib marks <NUM> on the cut plane of the work in progress <NUM> are left on a part, facing away from the second glass substrate <NUM>, of the first glass substrate <NUM>. Conversely, if the work in progress <NUM> is cut off from under the second glass substrate <NUM>, then rib marks <NUM> on the cut plane of the work in progress <NUM> will be left on a part, facing away from the first glass substrate <NUM>, of the second glass substrate <NUM>. That is to say, it can be said that a given glass panel unit <NUM> has been separated from the work in progress <NUM> if at least one of the side surfaces of the glass panel unit <NUM> is the cut plane and the rib marks <NUM> are left on a part, facing away from the other glass panel <NUM>, <NUM>, of one glass panel <NUM>, <NUM>. In this case, it may be determined, by checking the shape of the outer side surfaces of the frame member <NUM>, whether or not a side surface of the glass panel unit <NUM> is a cut plane. If the side surface of the glass panel unit <NUM> is a cut plane, then the outer side surface of the frame member <NUM> is a flat surface as shown in <FIG>. In particular, this flat surface seems to be flush with the respective side surfaces of the pair of glass panels <NUM>, <NUM>. On the other hand, unless the side surface of the glass panel unit <NUM> is a cut plane, the outer side surface of the frame member <NUM> is highly likely a raised surface as shown in <FIG> and <FIG>. In that case, the outer side surface of the frame member <NUM> may be recessed inward with respect to the respective side surfaces of the pair of glass panels <NUM>, <NUM> as shown in <FIG>. Conversely, the outer side surface of the frame member <NUM> may also protrude out of the glass panel unit <NUM> with respect to the respective side surfaces of the pair of glass panels <NUM>, <NUM> as shown in <FIG>. Therefore, the glass panel unit <NUM> obtained by the manufacturing method described above includes a pair of glass panels <NUM>, <NUM> arranged to face each other and a frame member <NUM> disposed between the pair of glass panels <NUM>, <NUM> to hermetically bond the pair of glass panels <NUM>, <NUM> together. The outer side surface of the frame member <NUM> is an at least partially flat surface. In particular, in the glass panel units 10A, 10B, 10E, <NUM>, the frame member <NUM> includes a first part 40a with the raised outer side surface (see <FIG> and <FIG>) and a second part 40b with a flat outer side surface (see <FIG>). In this case, the first part 40a is a part corresponding to the peripheral wall <NUM>. The second part 40b is a part corresponding to the boundary walls <NUM> (see <FIG>). The first part 40a and the second part 40b may have an equal width. Nevertheless, the widths of the first part 40a and the second part 40b do not have to be exactly equal to each other but may be approximately equal to each other to the human eye.

By performing the removing step described above, glass panel units 10A-<NUM> are obtained from the work in progress <NUM> as shown in <FIG>. At this time, parts <NUM> (11A, 11B) including the second spaces 520a, 520b are obtained but are not used.

Note that the embodiment described above is only an example of the present disclosure and should not be construed as limiting. Rather, the embodiment may be readily modified in various manners depending on a design choice or any other factor without departing from the scope as defined by the appended claims. Next, variations of the embodiment described above will be enumerated one after another.

In the embodiment described above, the glass panel units <NUM> have a rectangular shape. However, this is only an example and should not be construed as limiting. Alternatively, the glass panel units <NUM> may also have a circular, polygonal, or any other desired shape. That is to say, the first glass panel <NUM>, the second glass panel <NUM>, and the frame member <NUM> do not have to be rectangular but may also have a circular, polygonal, or any other desired shape. In addition, the respective shapes of the first glass substrate <NUM>, the second glass substrate <NUM>, the peripheral wall <NUM>, the partitions <NUM>, and the reinforcing walls <NUM> do not have to be the ones used in the embodiment described above, but may also be any other shapes that allow glass panel units <NUM> of a desired shape to be obtained. Note that the shape and dimensions of the glass panel units <NUM> may be determined according to the intended use of the glass panel units <NUM>.

The pair of glass panels <NUM>, <NUM> does not have to have the same planar shape and planar dimensions and does not have to have the same thickness, either. In addition, the pair of glass panels <NUM>, <NUM> does not have to be made of the same material, either. The same statement applies to the pair of glass substrates <NUM>, <NUM> as well.

The frame member <NUM> does not have to have the same planar shape as the pair of glass panels <NUM>, <NUM>. Likewise, the peripheral wall <NUM>, <NUM> does not have to have the same planar shape as the pair of glass substrates <NUM>, <NUM>, either.

The first sealant of the peripheral wall <NUM> (peripheral wall <NUM>) and the second sealant of the partitions 420a-420p (boundary walls 42a-<NUM>) do not need to include the same core material but may include mutually different core materials. Furthermore, the first sealant may consist essentially of a hot glue. Likewise, the second sealant may also consist essentially of a hot glue.

The partitions 420a-420p do not have to have a broader width than the peripheral wall <NUM>. Alternatively, the width of the partitions 420a-420p may be equal to or greater than, or equal to or less than, the width of the peripheral wall <NUM> (i.e., the width of the first to fourth sides 410a-410d thereof). In addition, the boundary walls 42a-<NUM> do not have to have a broader width than the peripheral wall <NUM>. Alternatively, the width of the boundary walls 42a-<NUM> may be equal to or greater than, or equal to or less than, the width of the peripheral wall <NUM> (i.e., the width of the first to fourth sides 41a-41d thereof).

Also, in the assembly <NUM>, the peripheral wall <NUM> is just provided between the pair of glass substrates <NUM>, <NUM> and does not bond the pair of glass substrates <NUM>, <NUM> together. Optionally, however, in the assembly <NUM> stage, the peripheral wall <NUM> may bond the pair of glass substrates <NUM>, <NUM> together. In short, in the assembly <NUM>, the peripheral wall <NUM> needs to be provided between the pair of glass substrates <NUM>, <NUM> and does not have to bond the pair of glass substrates <NUM>, <NUM> together.

In the embodiment described above, the one or more second air passages <NUM>, <NUM> include a particular air passage <NUM> which is larger than any of the one or more first air passages <NUM>, <NUM>. Alternatively, the dimension of each of the one or more second air passages <NUM>, <NUM> may be equal to or greater than, or equal to or less than, that of any of the one or more first air passages <NUM>, <NUM>. That is to say, the particular air passage <NUM> is not an essential constituent element. In addition, in the embodiment described above, the partition 420p separates the second spaces 520a, 520b from each other. However, the partition 420p does not have to separate the second spaces 520a, 520b from each other. In short, the coupling space is not an essential constituent element. Rather at least the evacuation spaces (first spaces 510a-<NUM>) and the ventilation space (second space 520a) need to be provided.

Furthermore, in the embodiment described above, the air passages <NUM> are the gaps between the partitions 420a-420p and the gaps between the partitions 420a-420p and the peripheral wall <NUM>.

Furthermore, in the embodiment described above, the internal space <NUM> is partitioned into the plurality of first spaces 510a-<NUM> and the plurality of second spaces 520a, 520b. However, the internal space <NUM> may be partitioned by at least one partition into one or more first spaces and one or more second spaces.

In the embodiment described above, a melting furnace is used to heat the peripheral wall <NUM>, the gas adsorbents <NUM>, and the partitions 420a-420p. However, heating may be conducted by any appropriate heating means. The heating means may be a laser beam, or a heat exchanger plate connected to a heat source, for example.

In the embodiment described above, the assembly <NUM> includes a plurality of air passages <NUM>. However, the number of the air passages <NUM> provided may be one or more. The shape of the air passages <NUM> is not particularly limited.

In the embodiment described above, the evacuation port <NUM> is provided through the second glass substrate <NUM>. However, this is only an example and should not be construed as limiting. Alternatively, the evacuation port <NUM> may be provided through the first glass substrate <NUM> or may also be provided through the peripheral wall <NUM> (peripheral wall <NUM>). In short, the evacuation port <NUM> just needs to be provided to connect the second space 520a, 520b to the external environment.

Furthermore, the getter of the gas adsorbents <NUM> is an evaporative getter in the embodiment described above. Alternatively, the getter may also be a non-evaporative getter.

In the embodiment described above, the gas adsorbents <NUM> have an elongate flat plate shape. However, the gas adsorbents <NUM> may also have any other shape. In addition, the gas adsorbents <NUM> do not have to be located at an end of the vacuum space <NUM>. Furthermore, in the embodiment described above, the gas adsorbents <NUM> are formed by applying a liquid including a powder of a getter (such as a dispersion liquid obtained by dispersing the powder of the getter in a liquid or a solution obtained by dissolving the powder of the getter in a liquid). However, this is only an example and should not be construed as limiting. Alternatively, the gas adsorbents <NUM> may include a substrate and a getter adhered to the substrate. Such gas adsorbents <NUM> may be obtained by immersing the substrate in a liquid including a powder of the getter and drying the substrate. Note that the substrate may have any desired shape and may have an elongate rectangular shape, for example. Still alternatively, the gas adsorbents <NUM> may also be a film formed to cover the surface of the second glass substrate <NUM> either entirely or only partially. Such gas adsorbents <NUM> may be obtained by coating the surface of the second glass substrate <NUM> with a liquid including a powder of the getter. Yet alternatively, the gas adsorbents <NUM> may be included in the pillars <NUM>. The pillars <NUM> including the gas adsorbents <NUM> may be obtained by making the pillars <NUM> of a material containing the getter. Alternatively, the gas adsorbents <NUM> may even be a solid matter made of the getter.

Furthermore, in the embodiment described above, the plurality of spacers <NUM> are arranged over the entire internal space <NUM> (i.e., in each of the first spaces 510a-<NUM> and the second spaces 520a, 520b). However, the pillars <NUM> do not have to be arranged in the second spaces 520a, 520b. Furthermore, in the embodiment described above, each glass panel unit <NUM> includes a plurality of pillars <NUM>. Alternatively, each glass panel unit <NUM> may include a single pillar <NUM>. Still alternatively, the glass panel unit <NUM> may include no pillars <NUM> at all.

Claim 1:
A method for manufacturing a glass panel unit, the method comprising an assembling step, a first melting step, an evacuation step, and a sealing step,
the assembling step including providing a glass panel unit assembly (<NUM>) having a pair of glass substrates (<NUM>, <NUM>) arranged to face each other; a peripheral wall (<NUM>) having a frame shape and disposed between the pair of glass substrates (<NUM>, <NUM>); a partition (420a-420p) provided to partition an internal space (<NUM>), surrounded with the pair of glass substrates (<NUM>, <NUM>) and the peripheral wall (<NUM>), into a first space (510a-<NUM>) and a second space (520a, 520b), the partition (420a-420p) being lower in height than the peripheral wall (<NUM>); an air passage (<NUM>) being formed by a gap between the partition (420a-420p) and another partition (420a-420p) or a gap between the partition (420a-420p) and the peripheral wall (<NUM>), connecting the first space (510a-<NUM>) and the second space (520a, 520b) together; and an evacuation port (<NUM>) connecting the second space (510a-<NUM>) to an external environment,
the first melting step including melting the peripheral wall (<NUM>) to hermetically bond the pair of glass substrates (<NUM>, <NUM>),
the evacuation step including evacuating the first space (510a-<NUM>) through the air passage (<NUM>), the second space (510a-<NUM>), and the evacuation port (<NUM>),
the sealing step including deforming the partition (420a-420p) to close the air passage (<NUM>), characterised in that
in the first melting step, the partition (420a-420p) comes into contact with the pair of glass substrates (<NUM>, <NUM>) after the peripheral wall (<NUM>) comes into contact with the pair of glass substrates (<NUM>, <NUM>).