Glass Unit

Abstract

A glass unit according to the present invention comprises a first glass sheet, a second glass sheet which is disposed facing the first glass sheet at a predetermined interval and which forms an internal space between the first glass sheet and the second glass sheet, a sealing material for sealing a gap at the circumferential edge of the first glass sheet and the second glass sheet, and a plurality of spacers disposed between the first glass sheet and the second glass sheet, and the glass unit is configured so that the internal space is depressurized so as to attain a vacuum state or a predetermined gas is injected into the internal space, the thickness of the first and second glass sheets is 5 mm or less, the pitch of the spacers is 15 mm or greater, and the difference in height between the highest spacer and the lowest spacer is 0.01 mm or less.

Description

[Technical field]

[0001] The present invention relates to a glazing unit. [Background technology]

[0002] In recent years, glass units made of insulating glass have been widely adopted as window glass for buildings, etc. In such glass units, as described in Patent Document 1, for example, a reduced-pressure internal space is formed between two or more glass sheets, and a plurality of spacers that support the glass sheets are arranged in this internal space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-321255 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the spacer as described above is either bonded to the glass plates with an adhesive or fixed by the pressing force from the two glass plates without using an adhesive. In either case, if the spacer and the glass plates are not fixed sufficiently, the spacer may come off between the two glass plates. If the spacer comes off in this way, there is a risk that the glass plates may come into contact with each other. The present invention has been made to solve this problem, and has an object to provide a glass unit that can prevent the spacer from coming off. [Means for solving the problem]

[0005] Item 1. A first glass plate; a second glass plate disposed opposite the first glass plate at a predetermined distance and forming an internal space between the first glass plate and the second glass plate; a sealant that seals a gap between the periphery of the first glass plate and the second glass plate; a plurality of spacers disposed between the first glass plate and the second glass plate; Equipped with The internal space is decompressed to 50.7 KPa or less, The first and second glass plates have a thickness of 5 mm or less; The pitch of the spacers is 15 mm or more, A glass unit configured such that the difference in height between the highest spacer and the lowest spacer is within 0.01 mm.

[0006] Item 2. A first glass plate; a second glass plate disposed opposite the first glass plate at a predetermined distance and forming an internal space between the first glass plate and the second glass plate; a sealant that seals a gap between the periphery of the first glass plate and the second glass plate; a plurality of spacers disposed between the first glass plate and the second glass plate; Equipped with The internal space is decompressed to 50.7 KPa or less, The thickness of the first and second glass plates is 3.1 mm or less; A glass unit, wherein the pitch of the spacers is 20 mm or more.

[0007] Item 3. The glass unit according to item 1 or 2, wherein each of the spacers is in direct contact with at least one of the first glass plate and the second glass plate.

[0008] Item 4. The glass unit according to any one of Items 1 to 3, wherein the height of each of the spacers is 0.1 to 0.5 mm.

[0009] Item 5. The glass unit according to any one of Items 1 to 4, wherein the internal space is reduced in pressure to 2.67 Pa or less.

[0010] Item 6. The glass unit according to any one of Items 1 to 5, wherein the spacers have a pitch of 20 mm or more and a diameter of 0.5 mm or less.

[0011] Item 7. The glass unit according to any one of items 1 to 6, wherein the Young's modulus of at least one of the spacers adjacent to the sealing material is 100 GPa or more.

[0012] Item 8. The cross-sectional area of ​​the spacer is 0.03 mm 2 8. The glass unit according to any one of items 1 to 7, wherein Effect of the Invention

[0013] According to the glass unit of the present invention, it is possible to prevent the spacer from coming off. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a plan view showing an example of a glass unit according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of FIG. [Diagram 3] FIG. 13 is a plan view showing an example of a cover with adhesive disposed thereon. [Figure 4] 1 is a graph showing the relationship between the spacer pitch and the minimum distance between two glass plates in a glass unit using glass plates of different thicknesses. [Diagram 5] 11 is a cross-sectional view illustrating a state in which both glass plates are bent when the spacer pitch is 30 mm. FIG. [Figure 6] 13 is a cross-sectional view illustrating a state in which both glass plates are bent when the spacer pitch is 40 mm. FIG. [Figure 7] 2A to 2C are schematic cross-sectional views illustrating a manufacturing process for the glass unit of FIG. [Figure 8] FIG. [Figure 9] 1 is a graph showing the relationship between the thermal conductivity of a spacer and the thermal transmittance of a glass unit when the spacer pitch is 20 mm. [Figure 10] 1 is a graph showing the relationship between the thermal conductivity of a spacer and the thermal transmittance of a glass unit when the spacer pitch is 15 mm. [Figure 11]FIG. 13 is a plan view showing another example of the spacer. [Figure 12] FIG. 12 is a side view of FIG. [Figure 13] FIG. 11 is a side view showing another example of the spacer. [Figure 14] FIG. 13 is a plan view showing another example of the spacer. [Figure 15] FIG. 13 is a plan view showing another example of the spacer. [Figure 16] FIG. 16 is a cross-sectional view of FIG. [Figure 17] FIG. 13 is a plan view showing another example of the spacer. [Figure 18] FIG. 13 is a plan view showing another example of the spacer. [Figure 19] FIG. 13 is a plan view showing another example of the spacer. [Figure 20] FIG. 11 is a side view showing another example of the spacer. [Figure 21] FIG. 11 is a cross-sectional view showing another example of a spacer. [Figure 22] FIG. 11 is a cross-sectional view showing another example of a spacer. [Diagram 23] FIG. 11 is a cross-sectional view showing another example of a spacer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <1. Overview of the glass unit> Hereinafter, an embodiment of the glass unit according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view of the glass unit according to this embodiment, and FIG. 2 is a cross-sectional view of FIG. 1. As shown in FIGS. 1 and 2, the glass unit according to this embodiment has two rectangular glass plates, that is, a first glass plate 1 and a second glass plate 2. In this embodiment, the second glass plate 2 shown on the lower side in FIG. 2 is formed to be slightly larger than the first glass plate 1. A plurality of spacers 3 are disposed between the two glass plates 1 and 2, and these spacers 3 form a gap of a predetermined interval between the two glass plates 1 and 2. In addition, the gap at the periphery of the two glass plates 1 and 2 is sealed with a sealing material 4, and thus a sealed internal space 100 is formed between the two glass plates 1 and 2. Furthermore, a through hole 11 is formed in the first glass plate 1, and a plate-shaped cover 5 that closes the through hole 11 is provided. This cover 5 is fixed to the first glass plate 1 via an adhesive 6. Hereinafter, each member will be described.

[0016] <2. First glass plate and second glass plate> The material constituting the first glass plate 1 is not particularly limited, and a known glass plate can be used. Depending on the application, various glass plates can be used, such as, for example, figured glass, frosted glass with a light diffusion function provided by surface treatment, wired glass, lined glass plate, tempered glass, double-strengthened glass, low-reflection glass, high-transmittance glass plate, ceramic glass plate, special glass with a heat ray and ultraviolet ray absorption function, or a combination thereof. The thickness of the first glass plate 1 is not particularly limited, but is preferably, for example, 0.3 to 5 mm, more preferably 0.5 to 4 mm, and particularly preferably 1.0 to 3.1 mm.

[0017] The above-mentioned through hole 11 is formed at the end of the first glass plate 1. This through hole 11 is composed of a small diameter portion 111 arranged on the internal space 100 side, and a large diameter portion 112 that is continuous with the small diameter portion 111 and opens to the outside. The small diameter portion 111 and the large diameter portion 112 are formed in a coaxial cylindrical shape, and the inner diameter of the large diameter portion 112 is larger than the small diameter portion 211. Therefore, an annular step 113 facing outward is formed between the large diameter portion 112 and the small diameter portion 111.

[0018] The inner diameter of the small diameter portion 111 can be, for example, 1.0 to 3.0 mm. On the other hand, the inner diameter of the large diameter portion 112 can be larger than the small diameter portion 111 and can be 5 to 15 mm. By making it 5 mm or more, the small diameter portion 111 can be secured accordingly, so that, as described later, air can be efficiently discharged when the internal space 100 is made into a reduced pressure state. In addition, as described later, the space of the step 113 on which the adhesive 6 is placed can be secured, and this can prevent the adhesive 6 from blocking the small diameter portion 111 before it melts. On the other hand, by making it 15 mm or less, the through hole 11 can be made inconspicuous.

[0019] The difference in diameter between the large diameter portion 112 and the small diameter portion 111 can be, for example, 3 to 20 mm. By making the difference in diameter 3 mm or more, it is possible to properly secure the space for placing the adhesive 6, as described below. If the difference in diameter is too large, the appearance will be poor, so it is preferable to set the upper limit at 20 mm.

[0020] The depth of the large diameter portion 112, that is, the length in the axial direction, can be set to, for example, 0.5 to 1.5 mm.

[0021] The second glass plate 2 can be made of the same material and have the same thickness as the first glass plate 1. As described above, the second glass plate 2 is slightly larger than the first glass plate 1, and the above-mentioned sealant 4 is disposed on the portion of the periphery of the second glass plate 2 that protrudes beyond the first glass plate 1, and this sealant 4 seals the gap between the peripheries of both glass plates 1 and 2.

[0022] Furthermore, each of the glass plates 1 and 2 may be a glass plate that has been subjected to strengthening such as chemical strengthening or air-cooling strengthening. In particular, the second glass plate 2 may be strengthened since no through-holes are formed therein and therefore it is possible to prevent the degree of strengthening from decreasing in the heating process of the sealing material and adhesive described below. Air-cooling strengthening is more advantageous than chemical strengthening from the viewpoint of cost, but there is a risk that the degree of strengthening will decrease in the heating process of the sealing material 4 and adhesive 6 described below. In contrast, chemical strengthening can prevent the degree of strengthening from decreasing even in the heating process.

[0023] <3. Cover and adhesive> The cover 5 is formed in a disk shape, and its outer diameter is smaller than the large diameter portion 112 of the through hole 11 in the first glass plate 1, but larger than the small diameter portion 111. Therefore, the cover 5 is arranged to be placed on a step 113 between the large diameter portion 112 and the small diameter portion 111. As will be described later, in the decompression step, air is sucked from between the cover 5 and the through hole 11, so a gap is required between the outer peripheral surface of the cover 5 and the inner peripheral surface of the large diameter portion 112. For this reason, The cover 5 preferably has an outer diameter smaller than the inner diameter of the large diameter portion 112 by 0.2 to 1.5 mm.

[0024] Also, the thickness of the cover 5 is smaller than the depth of the large diameter portion 112, and for example, it is preferable that the difference between the depth of the large diameter portion 112 and the thickness of the cover 5 is 0.4 to 0.7 mm. As described later, the surface of the cover 5 is disposed on approximately the same plane as the surface of the first glass plate 1, so the difference between the depth of the large diameter portion 112 and the thickness of the cover 5 is the thickness of the adhesive 6 described above. Therefore, for example, if this difference is smaller than 0.4 mm, the thickness of the adhesive 6 becomes small, and there is a risk of the adhesive strength decreasing. On the other hand, if this difference is larger than 0.7 mm, the thickness of the adhesive 6 becomes large, but in this case, as described later, the heat for melting the adhesive 6 is not uniformly transferred to the adhesive 6, and there is a risk of the adhesive strength decreasing. Also, the thickness of the cover 5 or the thickness of the first glass plate 1 becomes thin, and there is a possibility of cracking.

[0025] The material constituting the cover 5 is not particularly limited as long as it is non-breathable and has a melting point higher than the heating temperature when melting the adhesive 6 and the sealing material 4, but it is preferable that the cover 5 is made of a material having the same thermal expansion coefficient as the first glass plate 1, and it is particularly preferable that the cover 5 is made of the same material as the first glass plate 1. This makes it possible to make the difference in thermal expansion between the cover 5 and the adhesive 6, and the difference in thermal expansion between the first glass plate 1 and the adhesive 6 the same, and makes it possible to prevent the first glass plate 1 and the cover 5 from cracking in the manufacturing process described below.

[0026] The adhesive 6 is not particularly limited as long as it can bond the cover 5 to the first glass plate 1, and may be, for example, one containing low-melting glass or metal solder. The low-melting glass may be, for example, lead-based, tin phosphate-based, bismuth-based, or vanadium-based. The low-melting glass may contain a filler or the like as an additive. These may be either crystalline or non-crystalline. Non-crystalline low-melting glass foams in the decompression step as described below, but has good fluidity, making it easy to fix the cover 5. On the other hand, crystalline low-melting glass is difficult to foam in the decompression step, so it has high sealing performance but may have low fluidity.

[0027] As will be described later, the adhesive 6 melts, then cools and solidifies. In order to prevent the first glass plate 1 from cracking due to the contraction of the adhesive 6 when solidified, the difference between the thermal expansion coefficient of the first glass plate 1 and the thermal expansion coefficient of the adhesive 6 is set to be less than 20×10 when the temperature is raised from room temperature to 300° C. -7 mm / °C or less. When the adhesive 6 contains glass as described above, the adhesive becomes the same quality as the first glass plate 1 to be bonded, and the difference in the thermal expansion coefficient can be particularly small. As a result, for example, when the adhesive 6 is heated and fixed, the difference in the thermal expansion coefficient with the first glass plate 1 is small, and cracks can be suppressed.

[0028] The thickness of the adhesive 6 is set to be the difference between the depth of the large diameter portion 112 and the thickness of the cover 5 in the final product. As described below, the adhesive 6 is heated to melt, and then cooled to solidify. Therefore, the thickness of the adhesive 6 before heating can be made greater than the thickness after heating. Also, when the adhesive 6 is heated and melted, for example, air may enter and cause the adhesive 6 to expand. In such a case, the thickness of the adhesive 6 before heating can be made smaller than the thickness after heating.

[0029] The adhesive 6 may be placed directly on the step 113 of the through hole 11, or may be attached to the cover 5 in advance and then the cover 5 attached to the through hole 11. In this case, the adhesive 6 can be fixed to the cover 5 by provisional baking. For example, when a bismuth-based low melting point glass is used as the adhesive 6, provisional baking can be performed at about 420 to 460°C. Alternatively, the adhesive 6 can be attached to the cover 5 by printing such as inkjet printing. When printed, the thickness of the adhesive 6 can be, for example, 0.2 mm or less.

[0030] The shape of the adhesive 6 may be formed in any position and shape that allows it to be disposed on the step 113 of the through hole 11, but it is particularly preferable to form it in a ring shape. However, as will be described later, in order to ensure an air passage during the decompression process, it is preferable to form the adhesive 6 in a discontinuous ring shape having at least one gap, for example, as shown in Fig. 3, a C-shape (a), a combination of multiple arcs spaced apart (b), or a radial arrangement (c).

[0031] <4. Encapsulating material> The sealing material 4 may be made of the same material as the adhesive 6. For example, it is preferable to use non-crystalline low-melting glass as the sealing material 4, since this has high fluidity and the sealing material 4 can be easily poured into the gap between the two glass plates 1 and 2. In this case, in order to improve sealing performance, it is preferable that the sealing material 4 penetrates from the end face of the first glass plate 1 by, for example, 2 to 7 mm.

[0032] As described above, low-melting glass or metal solder can be used as the sealing material 4, but when using the manufacturing process described below, it is necessary that the melting point of the adhesive 6 is higher than that of the sealing material 4. For example, when both the adhesive 6 and the sealing material 4 are the same type of low-melting glass, the melting point of the adhesive 6 can be made higher than that of the sealing material 4 by adjusting the amount of the low-melting glass and the amount of the filler as an additive.

[0033] From this viewpoint, for example, when low-melting glass is used as the sealing material 4, metal solder having a melting point lower than that of the low-melting glass cannot be used as the adhesive 6. On the other hand, metal solder can be used for both the sealing material 4 and the adhesive 6, but as described above, it is necessary to adjust the melting point of the adhesive 6 to be high.

[0034] <5. Spacer> Because the internal space 100 of the glass unit is decompressed, the two glass plates 1 and 2 sandwiching it are attracted to each other and bend toward the internal space. This bending may cause the two glass plates 1 and 2 to come into contact. To prevent this, a spacer 3 is placed between the two glass plates 1 and 2 to keep the distance between the two glass plates 1 and 2 constant.

[0035] The spacer 3 is formed in a cylindrical shape, but can also be formed in a polygonal column shape. The material for forming the spacer 3 is not particularly limited, and can be formed from various materials such as ceramics such as cordierite, mullite, and zirconia, resins such as PTFE (polytetrafluoroethylene), PEEK (polyether ether ketone), and PI (polyimide), and glass. However, it is preferable to use a material that does not contain carbon components. This is because if the spacer 3 contains carbon components, gas may be released from the spacer 3 into the internal space 100 due to changes over time, which may make it difficult to maintain a reduced pressure state. In addition, the release of gas may increase the heat transmission coefficient of the glass unit, which may reduce the heat insulation performance.

[0036] In addition, the spacer 3 is preferably made of a material with a large Young's modulus. This is because the spacer is required to support the glass plates 1 and 2, and the smaller the amount of contraction of the spacer 3 due to the stress generated when supporting the glass plates 1 and 2, the stronger the support for the glass plates 1 and 2. From this viewpoint, the spacer 3 is preferably made of ceramics such as cordierite, mullite, or zirconia.

[0037] As described above, the spacer 3 needs to have a certain degree of strength since it is sandwiched between the glass plates 1 and 2. From this viewpoint, the compressive strength of the spacer 3, although it depends on the pitch P of the spacer 3, is preferably 200 MPa or more, more preferably 400 MPa or more, further preferably 3000 MPa or more, and particularly preferably 4000 MPa or more.

[0038] In addition, the Young's modulus of the spacer 3 adjacent to the sealing material 4 is preferably high, and is preferably 100 GPa or more. This is for the following reason. For example, since the spacer 3 not adjacent to the sealing material 4 has spacers 3 arranged on both sides thereof, the spacers 3 on both sides are similarly subjected to pressure and compressed by decompression. Therefore, the spacer 3 having spacers 3 arranged on both sides is difficult to detach. In contrast, the sealing material 4 is difficult to shrink even by decompression, so if the spacer 3 adjacent to the sealing material 4 shrinks more than the sealing material 4 due to decompression, the spacer 3 may be detached. Therefore, it is preferable that the spacer 3 adjacent to the sealing material 4 has a high Young's modulus and is difficult to shrink.

[0039] In addition, when the spacer 3 is made of a brittle material such as zirconia, the fracture toughness value K IC is 1.0MPa m 1 / 2 The fracture toughness value is measured based on JIS R1607 for ceramics and glass, JIS G0564 for metals, and ISO 13586 for resins.

[0040] The arrangement method of the spacers 3 is not particularly limited, but it is preferable that they are arranged in a lattice pattern. In the following, unless otherwise specified, it is assumed that the plurality of spacers 3 are arranged in a lattice pattern. In addition, the pitch of the spacers 3 is preferably 15 mm or more, and more preferably 20 mm or more. This is from the viewpoint of preventing the spacers from coming off, as will be described later in detail. In addition, when the pitch of the spacers 3 is increased, the number of spacers arranged in the glass unit is reduced, and as will be described later, there is also an effect of reducing the heat transmission coefficient. On the other hand, the upper limit is preferably 60 mm or less, more preferably 40 mm or less, and particularly preferably 30 mm or less. This is because, if the pitch is widened, the amount of bending of the glass plate increases, which causes the glass plate to come into contact with both glass plates. In addition, the spacers 3 can be prevented from coming off, and the strength of the glass plates 1 and 2 can be reduced, thereby making it possible to reduce the thickness of the glass plates 1 and 2.

[0041] The cross-sectional shape of the spacer 3 is not particularly limited, and various shapes such as polygonal and circular are possible. However, if the cross section is circular, it is preferable because it can be machined on a lathe. This is because machining on a lathe has high accuracy. The diameter (outer diameter) of the spacer 3 is not particularly limited, but is preferably 0.1 mm or more and 0.4 mm or less, and more preferably 0.2 mm or more and 0.3 mm or less. This is because if the diameter of the spacer 3 is too large, the contact area with the glass plates 1 and 2 becomes large, and the heat insulating performance of the glass unit decreases. In particular, if the diameter of the spacer 3 exceeds 0.4 mm, it is difficult to cause bending as shown in FIG. 4 described later, so it is preferable to set the diameter to 0.4 mm or less. On the other hand, if the diameter of the spacer 3 is too small, the sound insulation performance of the glass unit decreases. If the diameter of the spacer 3 is large, the amount of bending of the glass plates 1 and 2 decreases, which contributes to preventing the spacer from coming off. In addition, if a preferable range of the cross-sectional area of ​​the spacer 3 is defined based on the diameter of the spacer 3 described above, it is, for example, 0.008 mm 2 More than 0.13mm 2 It is preferable that the value is less than 0.03 mm. 2 More than 0.07mm2 It is even more preferable that:

[0042] The height of the spacer 3 can be, for example, 0.1 to 2.0 mm, and more preferably 0.1 to 0.5 mm. The height of the spacer 3 is the distance between the two glass plates 1 and 2, that is, the thickness of the internal space 100, but the height of the spacer 3 may vary. In this embodiment, the variation in the height of the spacer 3 is set as follows.

[0043] (1) When the thickness of both glass plates 1, 2 is 5 mm or less and the spacer pitch is 15 mm or more, the difference in height between the highest spacer 3 and the lowest spacer 3 among the multiple spacers can be set to 0.01 mm or less.

[0044] (2) When the thickness of both glass plates 1, 2 is 3.1 mm or less and the spacer pitch is 20 mm or more, the difference in height between the highest spacer 3 and the lowest spacer 3 among the multiple spacers can be set to 0.02 mm or less.

[0045] The reason for this will be explained with reference to Figs. 4 and 5. First, condition (1) will be considered. Fig. 4 is a graph showing the relationship between the pitch P of the spacer 3 and the minimum distance between the two glass plates in a glass unit using glass plates of three different thicknesses when the pressure in the internal space is 50.7 kPa. The height of the spacer 3 in each glass unit is 0.2 mm. According to this graph, for example, when the thicknesses of the first glass plate 1 and the second glass plate 2 are both 5 mm, if the pitch P of the spacer 3 is 30 mm, the minimum distance between the two glass plates 1 and 2 is about 0.195 mm. That is, as shown in Fig. 5, if the pitch P of the spacer 3 is 30 mm, the glass plates 1 and 2 are deflected by about 0.005 mm in total between the adjacent spacers 3, and the minimum distance between the two glass plates 1 and 2 is about 0.195 mm.

[0046] Therefore, when the spacer pitch is 15 mm, if a spacer of 0.195 mm is placed, the spacer will come into contact with both glass plates. And, as shown in Fig. 4, the larger the spacer pitch, the greater the deflection of the glass plate, so if the spacer pitch is 15 mm or more, if a spacer with a height of 0.195 mm or more is placed, the spacer will necessarily come into contact with both glass plates. Therefore, if the thickness of the glass plate is 5 mm or less and the spacer pitch is 15 mm or more, it is preferable that the spacer height is 0.195 mm or more.

[0047] However, because there is variation in the height of the spacers, from this viewpoint, if the difference in height between the highest spacer 3 and the lowest spacer 3 is 0.01 mm or less, the spacer 3 arranged at the location where the glass plates 1, 2 are closest to each other will contact both glass plates 1, 2. On the other hand, if there is a large variation in the height of the spacers 3 and the difference in height between the highest spacer 3 and the lowest spacer 3 exceeds 0.01 mm, there is a risk that the spacer 3 arranged at the location where the glass plates 1, 2 are closest to each other will not contact both glass plates 1, 2. In other words, such a spacer 3 will contact only one of the glass plates 1, 2.

[0048] Next, condition (2) will be considered. As shown in FIG. 4, for example, when the thicknesses of the first glass plate 1 and the second glass plate 2 are both 3.1 mm, if the pitch P of the spacer 3 is 40 mm, the minimum distance between the two glass plates 1 and 2 is about 0.185 mm. That is, as shown in FIG. 6, if the pitch P of the spacer 3 is 40 mm, the glass plates 1 and 2 are bent by about 0.015 mm in total between the adjacent spacers 3, and the minimum distance between the two glass plates 1 and 2 is about 0.185 mm. In condition (2), the thickness of the glass plate is smaller than that in condition (1), but the smaller the thickness of the glass plate, the larger the amount of bending. However, if the pitch of the spacer 3 is 30 mm, the amount of bending is almost the same even if the thickness of the glass plates 1 and 2 is smaller, but if the pitch is larger, such as 40 mm or more, the amount of bending becomes larger.

[0049] Therefore, when the spacer pitch is 20 mm, if a spacer of 0.185 mm is placed, the spacer will come into contact with both glass plates. And, as shown in Fig. 4, the larger the spacer pitch, the greater the deflection of the glass plate, so if the spacer pitch is 20 mm or more, if a spacer with a height of 0.185 mm or more is placed, the spacer will necessarily come into contact with both glass plates. Therefore, if the thickness of the glass plate is 3.1 mm or less and the spacer pitch is 20 mm or more, it is preferable that the spacer height is 0.185 mm or more.

[0050] However, because the height of the spacers varies, from this viewpoint, if the difference between the height of the highest spacer 3 and the height of the lowest spacer 3 is 0.02 mm or less, the spacer 3 arranged at the location where the glass plates 1, 2 are closest to each other will contact both glass plates 1, 2. On the other hand, if the variation in the height of the spacers 3 is large and the difference between the height of the highest spacer 3 and the height of the lowest spacer 3 exceeds 0.02 mm, the spacer 3 arranged at the location where the glass plates 1, 2 are closest to each other will not contact both glass plates 1, 2, and will only contact one of the glass plates 1, 2. However, even if the thickness of both glass plates 1, 2 is 3.1 mm or less, if the pitch of the spacers 3 is about 15 mm, the difference between the height of the highest spacer 3 and the height of the lowest spacer 3 can be 0.01 mm or less, as in condition (1).

[0051] There are several methods for fixing the spacer 3 to the glass plates 1 and 2. One of them is to fix the spacer 3 to both glass plates 1 and 2 with an adhesive. That is, the spacer 3 contacts the glass plates 1 and 2 via the adhesive. Another method is to fix the spacer 3 to the glass plates 1 and 2 without adhering to both glass plates 1 and 2, by pressing the spacer 3 with the sucked glass plates 1 and 2 due to the action of the internal space 100 in a reduced pressure state. That is, the spacer 3 directly contacts the glass plates 1 and 2. Therefore, if no adhesive is used, the fact that the spacer 3 contacts only one of the glass plates 1 and 2 as described above means that the spacer 3 cannot be fixed in a predetermined position. That is, the spacer 3 falls off. If the spacer 3 falls off, the internal space 100 in a reduced pressure state cannot sufficiently support the sucked glass plates 1 and 2, and there is a risk that the glass plates 1 and 2 will come into contact with each other. As described above, in this embodiment, the spacer 3 is configured according to the above conditions (1) and (2). As described above, the spacers 3 can be fixed to the glass plates 1 and 2 using either an adhesive or no adhesive, but it is also possible to fix only one of the ends of the spacer 3 with an adhesive. Also, it is possible to mix spacers 3 fixed with an adhesive and spacers 3 without an adhesive in one glass unit.

[0052] <6. Glass unit manufacturing method> Next, a method for manufacturing the glass unit will be described. First, a structure as shown in FIG. 7 is assembled. That is, a first glass plate 1 having the through holes 11 formed therein as described above and a second glass plate 2 are prepared. Next, a plurality of spacers 3 are arranged on the second glass plate 2, and then the first glass plate 1 is arranged thereon. Note that the spacers 3 may simply be arranged on the second glass plate 2 as described above, or may be fixed on the second glass plate 2 by an adhesive.

[0053] Furthermore, a sealing material 40 is placed on the periphery of the second glass plate 2 so as to seal the gap between the peripheries of both glass plates 1 and 2. This is the sealing material 4 before it is melted and solidified.

[0054] As described above, the C-shaped adhesive 6 is attached to one surface of the cover 5 by pre-baking or the like. Then, the cover 5 is attached to the through hole 11 of the first glass plate 1. At this time, the adhesive 6 is arranged on the step 113 of the through hole 11. Next, a disk-shaped protective plate 7 larger than the large diameter portion 112 of the through hole 11 is arranged on the cover 5, and further a weight 8 is arranged on the protective plate 7. As a result, the cover 5 is pressed against the step 113 by the weight 8 via the protective plate 7.

[0055] At this time, since the adhesive 6 has been provisionally baked and solidified, it is not crushed, and a gap is formed between the cover 5 and the step 113 by the adhesive 6. Also, a cross-shaped groove 71 is formed on the underside of the protective plate 7, as shown in Fig. 8. Therefore, air flows between the internal space 100 of the glass unit and the outside via the small diameter portion 111 of the through hole 11, the discontinuous portion of the adhesive 6, the gap between the large diameter portion 112 and the cover 5, and the groove 71 of the protective plate 7.

[0056] As described later, since the protective plate 7 needs to transmit heat, it is preferable that the protective plate 7 is made of a material that absorbs little infrared rays and has a low expansion rate when heated. For example, quartz glass or the same material as the cover 5 and the glass plates 1 and 2 can be used. Note that the protective plate 7 may be made of any material that does not prevent the adhesive 6 from being heated by radiant heat from a heater 92 described later, and may be transparent or opaque.

[0057] The weight 8 may be shaped to press the periphery of the protection plate 7 so as not to block the cover 5, and may be formed, for example, in a doughnut shape. However, the weight 8 must be shaped to ensure the above-mentioned air flow path. In other words, the weight 8 must be structured so that the groove 71 of the protection plate 7 is open to the outside.

[0058] After the protective plate 7 and weight 8 are placed in this manner, a cup-shaped closing member 9 is attached to the upper surface of the first glass plate 1 so as to cover them. This seals the space surrounded by the closing member 9, including the through-hole 11. An opening 91 is formed in the upper part of the closing member 9, and this opening 91 is connected to a vacuum pump (not shown) so as to reduce the pressure in the internal space 100. Furthermore, inside the closing member 9, a heater 92 made of tungsten or the like is provided above the protective plate 7, and the adhesive 6 is heated by this heater 92.

[0059] After the closing member 9 is attached in this way, these are placed in a heating furnace (not shown) and heated. First, the sealing material 40 is heated to a temperature equal to or higher than the melting point thereof to melt the sealing material 40. The melted sealing material 40 penetrates into the gaps between the peripheries of the glass plates 1 and 2. When, for example, bismuth-based low-melting-point glass is used as the sealing material 40, the material is heated to about 470°C. Thereafter, the temperature of the heating furnace is lowered to, for example, about 380 to 460°C to solidify the sealing material 40. Since the heating temperature at this time is lower than the melting point of the adhesive 6, the adhesive 6 does not melt. Therefore, the above-mentioned air flow path is secured. The means for heating the sealing material 40 is not particularly limited, and radiation heating, laser heating, induction heating, and the like can be adopted. In particular, when the sealing material 40 is a metal, induction heating can be adopted.

[0060] Next, the vacuum pump is driven to reduce the pressure. That is, the pressure in the internal space 100 is reduced through the air flow path described above. The degree of reduction is not particularly limited, but is preferably 50.7 KPa or less, more preferably 2.67 Pa or less, and particularly preferably 0.1 Pa or less.

[0061] This decompression step applies a force in the direction in which both glass plates 1 and 2 approach each other, and the sealing material 40 is also crushed at the same time. This makes it possible to eliminate voids inside the sealing material 40, and therefore it is possible to prevent gas leakage through the sealing material 4. Therefore, it is preferable to start decompression at a temperature before the sealing material 40 is completely solidified, and the temperature for solidifying the sealing material described above (380 to 460°C in the above example) can be determined taking this into consideration. For example, decompression can be performed when the temperature becomes 50 to 150°C lower than the melting point of the sealing material 40. Note that, when the sealing material 40 is, for example, a metal solder, the sealing material 40 can be solidified without depending on the above-mentioned 380 to 460°C.

[0062] Following this, the heater 72 is driven to heat the adhesive 6. For example, when the adhesive 6 is made of bismuth-based low-melting-point glass, the temperature of the adhesive 6 is set to about 500°C by the heater 72. This melts the adhesive 6, and the adhesive 6 is crushed with the help of the pressure from the weight 8. As a result, the C-shaped adhesive 6 is deformed into a ring shape, and the small diameter part 111 of the through hole 11 is airtightly sealed by the cover 5 and the adhesive 6. In this way, the reduced pressure state of the internal space 100 is maintained. After that, the heater 72 is stopped to be driven and the whole is slowly cooled, whereby the sealing material 40 is completely solidified and serves as the sealing material 4 to seal the gaps around the edges of both glass plates 1 and 2. The above steps complete the glass unit. It should be noted that, as long as the adhesive 6 can be heated, a device other than the heater 72 described above may be used.

[0063] <7.Features> As described above, the present inventors have found that by configuring the spacer 3 according to the above-mentioned condition (1) or (2), it is possible to prevent the spacer 3 from coming off. This makes it possible to prevent the glass plates 1 and 2 from coming into contact with each other due to bending.

[0064] It should be noted that the control of the variation in height of the spacers 3 as described above may be performed in at least one of the above-mentioned regions depending on the intended use of the glass unit, but it is also possible to control the variation as described above in all regions.

[0065] It is also preferable that the pressure in the internal space 100 is low. This is because the greater the degree of pressure reduction, the smaller the thermal transmittance of the glass unit, and the greater the insulating effect.

[0066] This point was examined as follows: First, the glass unit shown in Table 1 below was created through simulation. [Table 1]

[0067] The thermal transmittance was calculated when the pressure in the internal space of the glass unit in Table 1 was changed. The results are as follows. [Table 2]

[0068] As shown in Table 2, the lower the pressure in the internal space, the lower the thermal conductivity of the glass unit. In particular, when the pressure in the internal space is 2.67 Pa or less, the thermal conductivity is 2.0 W / m 2 K or less, which shows that a higher insulation effect can be obtained.

[0069] Next, the occurrence of condensation will be considered. FIG. 9 is a graph showing the relationship between the thermal conductivity (horizontal axis) and the heat transmission coefficient (vertical axis) of the spacer when the spacer pitch is 20 mm and the spacer diameter is 0.2 to 0.6 mm (five types). Meanwhile, FIG. 10 is a graph showing the relationship between the thermal conductivity (horizontal axis) and the heat transmission coefficient (vertical axis) of the spacer when the spacer pitch is 15 mm and the spacer diameter is 0.2 to 0.6 mm (five types). In both cases, the conditions are the same as those in Table 1 except for the thermal conductivity of the spacer, and the pressure of the internal space is set to 1.33 Pa or less. Comparing FIG. 9 and FIG. 10, it can be seen that the smaller the pitch of the spacer 3, the more spacers 3 are provided in the glass unit, so the heat transmission coefficient increases and the insulation performance decreases. Also, when each of FIG. 9 and FIG. 10 is examined, it can be seen that the lower the diameter of the spacer 3, the lower the heat transmission coefficient, but even if the thermal conductivity of the spacer 3 increases, the heat transmission coefficient does not change much. In other words, even if the material of the spacer 3 is changed, there is no significant change in the thermal conductivity.

[0070] For example, when the condensation conditions are -20°C inside the cabinet, 25°C outside the cabinet, and 70% humidity, the heat transfer coefficient is 1.2 W / m 2 It is known that condensation will occur if the temperature is less than K. Therefore, from Fig. 9, it can be seen that if the pitch of the spacers 3 is 20 mm or more and the diameter of the spacers 3 is 0.5 mm or less, condensation will not occur.

[0071] <8. Variations> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. The following modified examples can be combined as appropriate.

[0072] <8-1> In the above embodiment, the spacers 3 are arranged in a lattice pattern, but they do not necessarily have to be arranged in a lattice pattern as long as they can be arranged at the above-mentioned pitch. In addition, it is preferable that the above-mentioned spacer-related regulations such as pitch are applied to all spacers, but it is permissible for the above regulations to be slightly deviated from the above-mentioned regulations.

[0073] <8-2> The shape of the spacer 3 is not particularly limited as long as it can form a gap between the first glass plate 1 and the second glass plate 2, and can be various shapes other than the cylindrical shape described above. For example, the spacer 3 shown in Figs. 11 and 12 is formed in a disk shape and has both end faces 30 in the axial direction (direction from the first glass plate 1 to the second glass plate 2) and a peripheral wall surface 33 connecting these both end faces 30. Each end face 30 is formed in a spherical shape convex toward the glass plates 1 and 2. More specifically, each end face 30 has a contact surface 31 that is circular in plan view centered on the central axis X when viewed along the central axis X, and an annular non-contact surface 32 provided around the contact surface 31. Each contact surface 21 contacts each glass plate 1 and 2, respectively. On the other hand, the non-contact surface 32 extends radially outward from the periphery of the contact surface 31 and extends obliquely so as to move away from the glass plates 1, 2 as it moves away from the contact surface 31, so that it does not come into contact with the glass plates 1, 2 unless an external force is applied to the glass plates 1, 2.

[0074] In this way, the spacer 3 has the non-contact surface 32 located on the periphery of the contact surface 31, thereby making it possible to reduce the contact surface 21. In other words, it is possible to reduce the area of ​​contact with each of the glass plates 1 and 2. This makes it possible to reduce the thermal transmittance of the glass unit.

[0075] The contact surface 31 and the non-contact surface 32 constituting each end face 30 of the spacer 3 are formed into a spherical shape having the same radius as a whole. Specifically, the radius of curvature of each end face can be, for example, 0.3 mm or more and 20 mm or less. When the radius of curvature of the contact surface 31 and the non-contact surface 32 is set within a predetermined range in this manner, the contact surface 31 and the non-contact surface 32 can be easily formed.

[0076] When the contact surface 31 is formed in a spherical shape, the pressing force of the contact surface 31 against the first glass plate 1 and the second glass plate 2 is increased, so that the spacer 3 is easily held in position between the two glass plates 1, 2. Furthermore, when the contact surface 31 and the non-contact surface 32 are spherical with the same radius as a whole, the non-contact surface 32 is easily brought into contact with the deformed (curved) glass plates 1, 2. Furthermore, the spherical portion of the spacer 3 is easy to remove from a die when the spacer 3 is molded using a die, for example. Therefore, the spacer 3 can be molded at low cost.

[0077] Although the peripheral wall surface 33 extends parallel to the axial direction, it may be formed into a curved surface that is convex in the radial direction, as shown in Fig. 13, for example. As a result, the outer surface of the spacer 3, including both end surfaces 30, does not have a flat surface, and therefore this outer surface is not held in a position in which it abuts against the first glass plate 1 or the second glass plate 2. This makes it easier to arrange the spacer 3 on each of the glass plates 1 and 2. Also, as shown in Fig. 14, the outer shape of the spacer 3 in a plan view may be polygonal rather than circular.

[0078] <8-3> A protrusion may be provided on the non-contact surface 32 of the spacer 3 shown in Figs. 11 and 12. For example, as shown in Figs. 15 and 16, a ring-shaped protrusion 341 may be provided around the contact surface 31. The protrusions may not be continuous, and may be provided around the contact surface 31 at predetermined angular intervals around the central axis X, as shown in Figs. 17 and 18. In the example of Fig. 16, the protrusions 342 are provided at 90 degree intervals, and in the example of Fig. 17, the protrusions 342 are provided at 45 degree intervals. The shape of the protrusions 342 is not particularly limited, and may be a circular shape in plan view as shown in Figs. 17 and 18, or a rectangular shape in plan view as shown in Fig. 19. Therefore, the shape, number, and arrangement position of the protrusions 342 are not particularly limited.

[0079] In this way, by providing the protrusions 341, 342 on a part of the non-contact surface 32, the overall volume of the spacer 3 can be reduced compared to a case in which the non-contact surface 32 is offset toward the first glass plate 1 or the second glass plate 2 to a position where the non-contact surface 32 contacts the apexes of the protrusions 341, 342. The heat transmission coefficient (U value) of the spacer 3 is proportional to the volume of the spacer 3, and therefore, by forming the spacer 3 into the shapes shown in Figures 15 to 19, the heat transmission coefficient (U value) of the spacer 3 can be suppressed. Furthermore, by reducing the volume of the spacer 3, material costs can be reduced.

[0080] <8-4> 20, a groove 310 may be formed in the non-contact surface 32, and the contact surface 31 and the non-contact portion 32 may be arranged with the groove 310 sandwiched therebetween. In this way, by providing the groove 310 in the non-contact surface 32, the overall volume of the spacer 3 can be reduced. This allows the spacer 3 to reduce its thermal conductivity (U value), and also reduces material costs.

[0081] <8-5> 21, non-contact surface 32 may be configured as a flat surface that fits along glass plates 1, 2. When non-contact surface 32 is thus flat, deformed glass plates 1, 2 are supported by the flat surface of non-contact surface 32, thereby enhancing the impact strength of the glass unit.

[0082] <8-6> 22, a protrusion 35 may be formed on the outer edge of the non-contact surface 32 so as to protrude towards the glass plates 1 and 2. In other words, the non-contact surface may have projections and recesses.

[0083] <8-7> As shown in Fig. 23, the contact surface 31 may be formed as a flat surface, and the non-contact surface 32 may be formed as an inclined surface having a linear cross section. The spacers 3 shown in Figs. 11 to 23 are examples, and some or all of the configurations of the spacers 3 shown here may be combined as appropriate. In addition, the diameter and cross-sectional area of ​​the spacers 3 having a shape other than a cylinder, such as the spacers 3 shown in <8-2> to <8-7>, are defined as follows. That is, the diameter of the spacer 3 does not mean the outer diameter of the spacer 3, but the diameter of the portion in contact with either of the glass plates 1 and 2, and the cross-sectional area of ​​the spacer 3 means the cross-sectional area of ​​the portion in contact with either of the glass plates 1 and 2.

[0084] <8-8> In the above embodiment, the through hole 11 is formed in the first glass plate 1, the internal space 100 is reduced in pressure, and then the cover 5 is fixed, but the method of closing the through hole 11 is not particularly limited as long as the internal space 100 can be reduced in pressure. For example, a resin or glass pipe can be fixed to the through hole 11 with an adhesive, and after air is sucked through the pipe, the pipe can be melted to close the through hole 11. The cover 5 and the pipe may protrude from the surface of the first glass plate 1 to some extent.

[0085] <8-9> In the above embodiment, the second glass plate 2 is larger than the first glass plate 1, but they may have the same shape. In this case, the sealing material 4 is filled in the gaps around the peripheries of both glass plates 1, 2.

[0086] <8-10> After producing the glass unit as described above, a laminated glass consisting of the first glass plate 1, the interlayer film, and the third glass plate can be formed by placing the interlayer film and the third glass plate in this order on the first glass plate 1 and fixing them in a known autoclave. A known resin film used in laminated glass can be used as the interlayer film, and the same glass plate as the first glass plate 1 can be used as the third glass plate.

[0087] As described above, if the cover 5 is substantially flush with the surface of the first glass plate 1, the interlayer film and the third glass plate can be laminated without the cover 5 getting in the way. Therefore, in addition to using the first glass plate 1 that has been tempered as described above, the glass unit of the present invention can be made into safety glass by forming laminated glass.

[0088] <8-11> A known Low-E film may be laminated on at least one of the first glass plate 1 and the second glass plate 2 .

[0089] <8-12> The glass unit of the present invention can be used as a window glass for buildings requiring thermal insulation performance, as well as a cover glass to be attached to the outer surface of an apparatus (e.g., an apparatus such as a refrigerator). Either the first glass plate 1 or the second glass plate 2 may be arranged to face the outside of the apparatus, building, etc. to which it is attached, but since the first glass plate 1 having the through hole 11 formed therein has a lower strength than the second glass plate 2, it is preferable to face the second glass plate 2 to the outside. [Explanation of symbols]

[0090] 1 First Glass Pane 2. Second Glass Pane 3 Spacer 4. Encapsulating material

Claims

1. A first glass plate; a second glass plate disposed opposite the first glass plate at a predetermined distance and forming an internal space between the first glass plate and the second glass plate; a sealant that seals a gap between the peripheral edges of the first glass plate and the second glass plate; A plurality of cylindrical or disk-shaped spacers disposed between the first glass plate and the second glass plate; Equipped with The internal space is decompressed to 50.7 KPa or less, The thickness of the first and second glass plates is 5 mm or less. The pitch of the spacers is 15 mm or more, The height of each spacer is 0.1 to 0.5 mm; The compressive strength of the spacer is 3000 MPa or more; The difference in height between the highest spacer and the lowest spacer is within 0.01 mm; Each axial end face of the spacer has an abutment surface that abuts against the first glass plate or the second glass plate, and a non-abutment surface provided around the abutment surface, A glass unit in which the abutment surface and the non-abutment surface are formed into a spherical shape having the same radius of curvature overall of 0.3 mm or more and 20 mm or less, and are formed into a convex spherical shape toward the first glass plate side or the second glass plate side.

2. A first glass plate; a second glass plate disposed opposite the first glass plate at a predetermined distance and forming an internal space between the first glass plate and the second glass plate; a sealant that seals a gap between the peripheral edges of the first glass plate and the second glass plate; A plurality of cylindrical or disk-shaped spacers disposed between the first glass plate and the second glass plate; Equipped with The internal space is decompressed to 50.7 KPa or less, The thickness of the first and second glass plates is 3.1 mm or less; The height of each spacer is 0.1 to 0.5 mm; The compressive strength of the spacer is 3000 MPa or more; The difference between the height of the highest spacer and the height of the lowest spacer is 0.02 mm or less; The pitch of the spacers is 20 mm or more, Each axial end face of the spacer has an abutment surface that abuts against the first glass plate or the second glass plate, and a non-abutment surface provided around the abutment surface, A glass unit in which the abutment surface and the non-abutment surface are formed into a spherical shape having the same radius of curvature overall of 0.3 mm or more and 20 mm or less, and are formed into a convex spherical shape toward the first glass plate side or the second glass plate side.

3. 3. The glass unit according to claim 1, wherein each of the spacers is in direct contact with at least one of the first glass sheet and the second glass sheet.

4. 4. The glass unit according to claim 1, wherein the internal space is reduced in pressure to 2.67 Pa or less.

5. 5. The glass unit according to claim 1, wherein the spacers have a pitch of 20 mm or more and a diameter of 0.5 mm or less.

6. 6. The glass unit of claim 1, wherein the Young's modulus of at least one of the spacers adjacent the sealing material is 100 GPa or greater.

7. The cross-sectional area of ​​the spacer is 0.03 mm 2 The glass unit according to any one of claims 1 to 6.

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