Method for manufacturing flat glass, method for manufacturing wedge-shaped glass, and method for manufacturing laminated glass

Abstract

In the present invention, a molten metal bath is provided with an upstream wall, a downstream wall, and two side walls. Each of the two side walls includes a shoulder that reduces the width of the molten metal bath in the direction of advance of a glass ribbon. The ratio W / N of the distance W between the two side walls in a region upstream of the shoulders of the molten metal bath and the distance N between the two side walls in a region downstream of the shoulders of the molten metal bath is greater than 1.0 and no greater than 1.6. By heating a central section of the glass ribbon in the width direction in the upstream region of the molten metal bath more strongly than sections at both ends in the width direction, plate glass is manufactured in which the central section in the width direction is thicker than the sections at both ends.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing flat glass, a method for manufacturing wedge-shaped glass, and a method for manufacturing laminated glass. In particular, it relates to a method for manufacturing flat glass in which the cross-section in the width direction perpendicular to the direction of travel of the glass ribbon is convex (the center in the width direction is thicker than both ends in the width direction). [Background technology]

[0002] The thickness of plate glass manufactured by the float process is usually constant. However, in head-up displays (HUDs), which display information on the windshield of automobiles, for example, glass of varying thickness is required to prevent double images from appearing to the driver. Therefore, methods for manufacturing plate glass in which the cross-section in the width direction (hereinafter sometimes simply referred to as the width direction) perpendicular to the direction of travel of the glass ribbon is concave, convex, or tapered have been investigated (see, for example, Patent Documents 1 and 2). Patent Document 1 discloses obtaining wedge-shaped glass by cutting a plate glass with a convex cross-section where the center in the width direction is thicker than both ends in the width direction. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2016 / 117650 [Patent Document 2] U.S. Patent No. 7122242 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Typically, a molten metal bath comprises an upstream wall, a downstream wall, and two side walls. Each side wall may be provided with a shoulder that reduces the width of the molten metal bath in the direction of glass ribbon travel, thereby reducing the amount of molten metal in the bath. In such a molten metal bath with shoulders on the side walls, a flow in the opposite direction to the direction of glass ribbon travel may occur in the portion of the molten metal surface not covered by the glass ribbon. This reverse flow can cause the glass ribbon on the molten metal surface to be observed to move back and forth (swing) in the width direction as it travels.

[0005] In particular, when manufacturing a glass plate with a convex cross-section, as described in Patent Document 1, the temperature of the center of the glass ribbon in the width direction is set lower than when manufacturing a glass plate with a constant thickness. This increases the viscosity of the glass ribbon (making it harder), making it more susceptible to the effects of the reverse flow and prone to causing the glass ribbon to swing. Furthermore, when attempting to manufacture wedge-shaped glass by cutting a glass plate with a convex cross-section, as described in Patent Document 1, the cutting position of the glass plate is usually fixed. Therefore, if the aforementioned swing occurs, the wedge angle of the wedge-shaped glass will vary from product to product.

[0006] The present invention has been made in view of the above circumstances, and its objective is to provide a method for manufacturing flat glass that can suppress reciprocating movement (swing) in the width direction of the glass ribbon. Furthermore, it aims to provide a method for manufacturing wedge-shaped glass and laminated glass that can suppress variations in the wedge angle of wedge-shaped glass obtained by cutting the flat glass. In this invention, convex-shaped glass means a glass ribbon in which the center in the width direction is thicker than both ends in the width direction, or flat glass obtained from a glass ribbon. [Means for solving the problem]

[0007] The above objective of the present invention is achieved by the following configuration. [1] A method for manufacturing a glass plate, comprising floating a glass ribbon on the surface of a molten metal bath and advancing it, and bringing a plurality of top rolls into contact with both ends of the glass ribbon in the width direction to form the glass ribbon into a plate shape, The molten metal bath comprises an upstream wall, a downstream wall, and two side walls. Each of the two side walls includes a shoulder that reduces the width of the molten metal bath in the direction of the glass ribbon's movement. The ratio W / N of the distance W between the two side walls upstream of the shoulder of the molten metal bath and the distance N between the two side walls downstream of the shoulder of the molten metal bath is greater than 1.0 and less than or equal to 1.6. A method for manufacturing a glass plate, comprising heating the ends of the glass ribbon more strongly in the width direction than the center in the width direction in the upstream region of the molten metal bath, thereby producing a glass plate where the center in the width direction is thicker than the ends. [2] The method for manufacturing a glass plate according to [1], wherein the glass ribbon is heated so that at a position 20% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the viscosity of the central part of the glass ribbon in the width direction on the molten metal surface is 10^(4.5)(dPa·sec) or more. [3] A method for manufacturing a glass plate according to [1] or [2], wherein the glass ribbon is heated so that at a position 20% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the viscosity of the central part of the glass ribbon in the width direction on the molten metal surface is 10^(6.0)(dPa·sec) or less. [4] A method for manufacturing a glass plate according to any one of [1] to [3], wherein, at a position 32% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the difference between the temperature of the center of the glass ribbon in the width direction on the molten metal surface and the temperature of both ends of the molten metal in the width direction is 62°C or less. [5] A method for manufacturing a glass plate according to any one of [1] to [4], wherein the glass ribbon is heated so that at a position 32% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the viscosity of the central part of the glass ribbon in the width direction on the molten metal surface is 10^(4.7) (dPa·sec) or more. [6] A method for manufacturing a glass plate according to any one of [1] to [5], wherein the glass ribbon is heated so that at a position 32% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the viscosity of the central part of the glass ribbon in the width direction on the molten metal surface is 10^(6.3) (dPa·sec) or less. [7] A method for manufacturing a glass plate according to any one of [1] to [6], wherein the ratio of the maximum width in the width direction of the glass ribbon in the molten metal bath to the length in the width direction of the glass ribbon at the downstream end of the molten metal bath is 1.4 to 2.2. [8] A method for manufacturing a glass plate according to any one of [1] to [7], wherein the ratio a / b of the width a of the glass ribbon at a position 35% from the upstream wall to the length from the upstream wall to the downstream wall, and the width of the glass ribbon at the downstream end of the molten metal bath, is 1.0 to 1.9. [9] A method for manufacturing a plate glass according to any one of [1] to [8], wherein, with respect to the length from the upstream wall to the downstream wall, at a position 20% from the upstream wall, the ratio A / B of the widthwise length A of the glass ribbon to the widthwise length B of the molten metal surface not covered by the glass ribbon is 4 to 11. A method for producing wedge-shaped glass, comprising cutting a plate glass obtained by the plate glass manufacturing method described in any of [1] to [9]

[10] .

[11] The wedge-shaped glass has at least one main surface that is convex, A method for manufacturing a wedge-shaped glass according to

[10] , wherein, on a line segment that passes through the centroid G of the convex surface and connects two opposite sides of the four sides of the convex surface by the shortest distance, the point at which the wedge-shaped glass intersects with the sides of the convex surface, the point at which the thickness of the wedge-shaped glass in the vertical direction is smaller when the wedge-shaped glass is placed on a horizontal surface, is designated as the first point, and the point on the convex surface located at a distance of 2 / 5 of the length of the line segment from the first point is designated as the second point, and the angle between the line line connecting the first point and the second point and the horizontal plane is 0.020° to 0.050°.

[12] A method for manufacturing wedge-shaped glass according to

[10] or

[11] , wherein the ratio T / M of the maximum thickness T to the minimum thickness M of the wedge-shaped glass is 1.10 to 1.40.

[13] Cut the sheet glass obtained by the method for producing sheet glass according to any one of [1] to [9] to obtain wedge-shaped glass, laminate and press-bond the wedge-shaped glass and another sheet glass through an intermediate film, A method for producing laminated glass.

[14] The other sheet glass is the wedge-shaped glass, The method for producing laminated glass according to

[13] .

[15] The other sheet glass is a sheet glass having a constant thickness, The method for producing laminated glass according to

[14] .

Advantages of the Invention

[0008] It is possible to provide a method for producing sheet glass that can suppress the reciprocating movement in the width direction of the glass ribbon. Furthermore, it is possible to provide a method for producing wedge-shaped glass and laminated glass that can suppress the variation in the wedge angle of the wedge-shaped glass obtained by cutting the sheet glass.

Brief Description of the Drawings

[0009] [Figure 1] Fig. 1(A) is a view of the glass manufacturing apparatus seen from the width direction, and Fig. 1(B) is a view of the glass manufacturing apparatus seen from the thickness direction. [Figure 2] Fig. 2(A) is a cross-sectional view in the width direction of the glass manufactured by the manufacturing method of an embodiment of the present invention, and Fig. 2(B) is the wedge-shaped glass obtained by cutting the A portion of the glass in Fig. 2(A). [Figure 3] Fig. 3(A) is a plan view of the front glass, Fig. 3(B) is a cross-sectional view taken along the line B-B of the front glass in Fig. 3(A), and Fig. 3(C) is a cross-sectional view taken along the line C-C of the front glass in Fig. 3(A). [Figure 4] Fig. 4 is an enlarged view of the top roll. [Figure 5] Figs. 5(A) and (B) are views showing the sheet glass according to an embodiment of the present invention, Fig. 5(A) is a plan view, and Fig. 5(B) is a cross-sectional view in the width direction.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present invention will be described. First, the configuration of a glass manufacturing apparatus (i.e., a float plate glass manufacturing apparatus) will be described.

[0011] As shown in FIGS. 1(A) and (B), the glass manufacturing apparatus 1 includes a melting section 10, a forming section 20, and a lehr section 30. In the figures, the X direction is the traveling direction of the glass ribbon G2, X1 is the upstream direction of the glass ribbon G2, and the X2 direction is the downstream direction of the glass ribbon G2. The Y direction in the figures is the direction orthogonal to the traveling direction X of the glass ribbon G2 and is the width direction of the glass ribbon G2. The Z direction in the figures is the direction orthogonal to the traveling direction X and the width direction Y of the glass ribbon G2 (i.e., the thickness direction of the glass ribbon G2), the Z1 direction is upward, and the Z2 direction is downward. FIG. 1(A) is a view of the glass manufacturing apparatus 1 seen from the width direction Y, and FIG. 1(B) is a view of the glass manufacturing apparatus 1 seen from the thickness direction Z.

[0012] The melting section 10 includes a melting furnace 11, a tweel 12, and a lip 13. In the melting section 10, the glass raw material is melted into molten glass G1 in the melting furnace 11, and the amount of molten glass G1 supplied to the forming section 20 is adjusted by moving the tweel 12 in the vertical direction Z with respect to the lip 13 which is the flow path of the molten glass G1.

[0013] The forming section 20 includes a molten metal bath (float bath) 21, molten metal 22 stored in the molten metal bath 21, a plurality of top rolls 23, and a heater 24. In the forming section 20, the molten glass G1 continuously supplied from the melting section 10 is gradually cooled while flowing in the traveling direction X and formed into a glass ribbon G2. That is, the molten glass G1 is discharged in a glass ribbon shape onto the molten metal surface of the molten metal bath 21 (on the surface of the molten metal 22), and is advanced in the traveling direction X (downstream direction X2) while floating on the molten metal surface to be formed into the glass ribbon G2.

[0014] A molten metal bath 21 contains a molten metal 22, such as tin. Molten glass G1 is continuously supplied onto the surface of the molten metal 22 via the twill 12 and lip 13.

[0015] The molten metal bath 21 has an upstream wall 25 located on the upstream side, a downstream wall 26 located on the downstream side, and two side walls 27, 27 connecting the upstream wall 25 and the downstream wall 26. Each of the two side walls 27, 27 is provided with a shoulder 27A that reduces the width of the molten metal bath 21 (dimension in the width direction Y) in the direction of travel X of the glass ribbon G2. That is, the side wall 27 has a first wall 27B connected to the upstream wall 25 and extending linearly in the downstream direction X2, a shoulder 27A connected to the first wall 27B and extending inward in the width direction Y (towards the glass ribbon G2) as it moves downstream X2, and a second wall 27C connected to the shoulder 27A and extending linearly in the downstream direction X2. By providing the shoulder 27A in this way, the amount of molten metal 22 stored in the molten metal bath 21 is reduced.

[0016] The ratio W / N between the distance W (the distance between the two first walls 27B, 27B) between the two side walls 27, 27 in the upstream area above the shoulder 27A of the molten metal bath 21 and the distance N (the distance between the two second walls 27C, 27C) between the two side walls 27, 27 in the downstream area below the shoulder 27A of the molten metal bath 21 is set to be more than 1.0 and not more than 1.6 (1.0 < W / N ≦ 1.6). When manufacturing a convex glass, it is necessary to make the glass ribbon G2 have a convex cross-sectional shape in the upstream area of the molten metal bath 21 and make the width of the glass ribbon G2 smaller than when manufacturing a glass plate with a constant thickness. Therefore, the area of the molten metal 22 in the upstream area above the shoulder 27A that is not covered by the glass ribbon G2 tends to increase, and thus the reciprocating movement (swing) of the glass ribbon G2 in the width direction Y is more likely to occur than when manufacturing a glass plate with a constant thickness. If the ratio W / N is not more than 1.6, the area of the molten metal 22 in the upstream area above the shoulder 27A that is not covered by the glass ribbon G2 decreases. Therefore, in particular, the flow of the molten metal 22 in the upstream direction X1 that affects the reciprocating movement (swing) of the glass ribbon G2 is less likely to occur, and the reciprocating movement (swing) of the glass ribbon G2 in the width direction Y is also less likely to occur when manufacturing a wedge glass. If the ratio W / N is more than 1.0, the distance between the two side walls 27, 27 in the downstream area below the shoulder 27A can be narrowed, and the amount of the molten metal 22 in the molten metal bath 21 can be reduced.

[0017] The position where the first wall 27B and the shoulder 27A are connected is preferably 60% to 75% of the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)) (0.60L to 0.75L downstream in X2 from the upstream wall 25). If the position where the first wall 27B and the shoulder 27A are connected is 60% to 75% of the upstream wall 25, the area of ​​the molten metal 22 upstream of the shoulder 27A that is not covered by the glass ribbon G2 will not become too large when manufacturing wedge glass, and a sufficient molding area for the glass ribbon can be secured even when manufacturing glass of a constant thickness. The position where the first wall 27B and the shoulder 27A are connected is preferably 60% or more of the upstream wall 25, and more preferably 62% or more. The position where the first wall 27B and the shoulder 27A are connected is preferably 75% or less from the upstream wall 25, more preferably 70% or less, even more preferably 67% or less, and particularly preferably 65% ​​or less.

[0018] The position where the shoulder 27A and the second wall 27C are connected is preferably 65% ​​to 85% of the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)), which is 0.65L to 0.85L downstream in X2 from the upstream wall 25. If the position where the shoulder 27A and the second wall 27C are connected is 65% to 85% of the upstream wall 25, the area of ​​the molten metal 22 upstream of the shoulder 27A that is not covered by the glass ribbon G2 will not become too large when manufacturing wedge glass. Also, a sufficient molding area can be secured when manufacturing glass of a constant thickness. The position where the shoulder 27A and the second wall 27C are connected is preferably 65% ​​or more of the upstream wall 25, and more preferably 67% or more. The position where shoulder 27A and the second wall 27C are connected is preferably 85% or less from the upstream wall 25, more preferably 80% or less, even more preferably 76% or less, and particularly preferably 70% or less.

[0019] Multiple top rolls 23 rest on the upper surfaces of both ends G2B, G2B in the width direction of the glass ribbon G2. That is, the multiple top rolls 23 are in contact with both ends G2B, G2B in the width direction of the glass ribbon G2. The peripheral speed of each top roll 23 is adjusted to adjust the thickness of the glass ribbon G2.

[0020] The heater 24 is positioned above Z1 of the molten metal bath 21. The heater 24 is divided into, for example, a central heater 24A that heats the central part G2A in the width direction of the glass ribbon G2, and a pair of end heaters 24B, 24B that heat the width ends G2B, G2B of the glass ribbon G2 in the width direction. The central heater 24A and / or the end heaters 24B may be further divided in the direction of travel X and / or the width direction Y, in which case the temperature of the glass ribbon G2 can be easily controlled. In the illustrated example, two heaters 24 are positioned in the direction of travel X, divided into an area upstream of the shoulder 27A and a area including the shoulder 27A and an area downstream of the shoulder 27A. The width of the downstream heater 24 is set to be shorter than the width of the upstream heater 24, according to the relationship between the distance W and the distance N.

[0021] The annealing section 30 comprises an annealing chamber 31 and a conveying roll 32. In the annealing section 30, the glass ribbon G2 formed in the molding section 20 is continuously conveyed and annealed by the conveying roll 32 located in the annealing chamber 31. The speed at which the glass ribbon G2 moves between the molding section 20 and the annealing section 30 can be adjusted by adjusting the peripheral speed of the conveying roll 32. Here, because the top roll 23 rested on the upper surfaces of both ends G2B, G2B in the width direction of the glass ribbon G2 in the molding section 20, distortion occurs near the parts of both ends G2B, G2B in the width direction of the glass ribbon G2 where the top roll 23 rested. The glass ribbon G2 is pulled out from the annealing section 30, and both ends of the glass ribbon G2 that have been distorted by the top roll 23 are cut and removed by a cutting machine. Furthermore, the glass ribbon G2 is cut to a predetermined size by the cutting machine to obtain the glass product.

[0022] Next, we will describe the glass produced by the manufacturing method according to one embodiment of the present invention (i.e., the float glass manufacturing method).

[0023] Figure 2(A) is a cross-sectional view in the width direction of glass manufactured by the manufacturing method according to one embodiment of the present invention, and Figure 2(B) is a wedge-shaped glass obtained by cutting off portion A of the glass in Figure 2(A). Figure 3(A) is a plan view of a windshield using glass manufactured by the manufacturing method according to one embodiment of the present invention, Figure 3(B) is a cross-sectional view BB of the windshield in Figure 3(A), and Figure 3(C) is a cross-sectional view CC of the windshield in Figure 3(A).

[0024] The plate glass produced by the manufacturing method according to one embodiment of the present invention is a convex glass 100 that becomes thicker from both ends toward the center in the width direction Y, as shown in Figure 2(A). By cutting this convex glass 100 at a predetermined position (for example, part A in Figure 2(A)), a wedge-shaped glass 200 can be obtained in which one end is thicker than the other end in the width direction Y, as shown in Figure 2(B). According to the manufacturing method of the present invention, the reciprocating movement (swing) of the glass ribbon G2 in the width direction Y can be suppressed, so that the variation in the wedge angle β of the wedge-shaped glass 200 obtained by cutting the convex glass 100 (plate glass) formed from the glass ribbon G2 can be suppressed. Here, the convex glass 100 only needs to become thicker from both ends toward the center in the width direction Y, and both sides may be convex, or one surface may be flat and the other surface may be convex.

[0025] The wedge-shaped glass 200 is preferably used in the windshields 300 and 400 of automobiles equipped with a HUD, as shown in Figures 3(A) to (C). By using the wedge-shaped glass 200 in the windshields 300 and 400 in this way, the occurrence of double images as seen by the driver can be suppressed without using a special interlayer (for example, an interlayer with a wedge-shaped cross-section).

[0026] The wedge-shaped glass 200 is not limited to automobile windshields; it can also be used as train windows, windshields for motorcycle riders, or any other type of glass that can display information. Furthermore, the wedge-shaped glass 200 is not limited to information display glass in vehicles; it can be used in various other types of information display glass. In addition, it can be used in various devices that utilize continuous changes in transmission characteristics, even for applications other than information display.

[0027] Furthermore, the windshield 300 shown in Figure 3(B) is a laminated glass manufactured by laminating and pressing together wedge-shaped glass 301 and wedge-shaped glass 302 with an interlayer 303 sandwiched in between.

[0028] Another form of windshield is one in which one of the two panes of glass to be joined may be of uniform thickness. As shown in Figure 3(C), the windshield 400 is a laminated glass manufactured by laminating and pressing together a wedge-shaped glass 401 and a glass of uniform thickness 402 with an interlayer 403 in between.

[0029] Next, a method for manufacturing flat glass according to one embodiment of the present invention will be described. In a method for manufacturing flat glass according to one embodiment of the present invention, when manufacturing a convex glass 100 in which the cross-section in the width direction Y perpendicular to the direction of travel X of the glass ribbon is convex, the glass ribbon G2 formed by continuously supplying molten glass G1, which is melted in the melting section 10, onto the molten metal 22 is heated more strongly at both ends G2B, G2B in the width direction than at the center G2A in the width direction in the upstream region of the molten metal bath 21. By heating both ends G2B, G2B in the width direction of the glass ribbon G2 more strongly than at the center G2A in the width direction, the viscosity of both ends G2B, G2B in the width direction of the glass ribbon G2 does not increase as easily as at the center G2A in the width direction. As a result, the thickness of both ends G2B, G2B in the width direction of the glass ribbon G2 tends to be thinner, while the thickness of the center G2A in the width direction tends to be thicker.

[0030] Furthermore, when manufacturing convex glass in the conventional float glass manufacturing apparatus 1 described above, it is preferable to heat the molten metal bath 21 using only the end heaters 24B located at both ends in the width direction, without substantially using the central heater 24A located in the center in the width direction in the upstream area. Here, "upstream area" refers to the 70% area upstream of the molten metal bath 21, close to the melting furnace 11. Also, "substantially not using the central heater 24A" means that the output of the central heater 24A is 1 kW / m². 2 This means it is less than [a certain value]. By substantially not using the central heater 24A and heating only with the end heaters 24B, the viscosity of the glass ribbon at both ends G2B,G2B in the width direction does not increase as much as the central G2A in the width direction, resulting in thinner glass ribbon ends G2B,G2B in the width direction and thicker central G2A in the width direction. The output of the central heater 24A is 0 kW / m 2 Alternatively, the central part G2A in the width direction may be cooled.

[0031] In the "downstream region," which is the 30% of the molten metal bath 21 closest to the slow-cooling chamber 31, the central part G2A in the width direction of the glass ribbon may be heated by the central heater 24A.

[0032] Furthermore, it is preferable to heat the glass ribbon G2 on the molten metal surface such that the cooling rate at both ends G2B, G2B in the width direction is 6.1°C / m or less. Here, "cooling rate" refers to the amount of temperature decrease when the glass ribbon G2 travels 1 m in the direction of travel X in the molten metal bath 21. If the cooling rate at both ends G2B, G2B of the glass ribbon G2 in the width direction is 6.1°C / m or less, the viscosity at both ends G2B, G2B in the width direction will not increase easily, the ends G2B, G2B in the width direction will be thin, and the center G2A in the width direction will be thicker. It is more preferable that the cooling rate at both ends G2B, G2B in the width direction is 6.0°C / m or less, and even more preferable that it is 5.9°C / m or less. In this specification, when the cooling rate at the ends of the glass ribbon G2 in the width direction is indicated, the ends refer to a position 50 mm from the end of the glass ribbon G2 towards the center in the width direction.

[0033] On the other hand, it is preferable to heat the glass ribbon G2 so that the cooling rate of both ends G2B, G2B in the width direction is 3.0°C / m or higher. If the cooling rate of both ends G2B, G2B in the width direction is 3.0°C / m or higher, the glass ribbon G2 will cool down sufficiently. The cooling rate of both ends G2B, G2B in the width direction may be 4.0°C / m or higher, or 5.0°C / m or higher.

[0034] It is preferable that the cooling rate of the ends G2B, G2B in the width direction of the glass ribbon G2 is slower than the cooling rate of the central part G2A in the width direction of the glass ribbon G2. If the cooling rate of the ends G2B, G2B in the width direction is slower than the cooling rate of the central part G2A in the width direction, the viscosity at both ends will not increase easily, and the ends G2B, G2B in the width direction will be thinner, while the central part G2A in the width direction will be thicker.

[0035] The cooling rate of the ends G2B, G2B in the width direction of the glass ribbon G2 is preferably 0.3°C / m or more slower than the cooling rate of the central part G2A in the width direction of the glass ribbon G2. If it is 0.3°C / m or more slower, the viscosity of the ends G2B, G2B in the width direction will not increase easily, and the ends G2B, G2B in the width direction will be thinner, while the central part G2A in the width direction will be thicker. The cooling rate of the ends G2B, G2B in the width direction may be 0.4°C / m or more slower than the cooling rate of the central part G2A in the width direction, and may also be 0.5°C / m or more slower.

[0036] Furthermore, the viscosity of the widthwise ends G2B, G2B of the glass ribbon G2 on the molten metal surface is 10 4.9 (dPa·sec) position and 10 6.1It is preferable to control the heating temperature of the widthwise ends G2B, G2B so that the distance to the position with (dPa·sec) is 15m or more. If the distance is 15m or more, the viscosity of the widthwise ends G2B, G2B will not increase easily, the widthwise ends G2B, G2B will be thin, and the widthwise center G2A will be thicker. The distance is more preferably 16m or more, and even more preferably 16.5m or more. Here, the viscosity of the glass ribbon G2 is calculated by measuring the temperature of the glass ribbon G2 with a radiation thermometer and using the glass viscosity curve (Fulcher formula) from the measured temperature. In this specification, when the viscosity of the widthwise end of the glass ribbon G2 is expressed, as described above, the end refers to a position 50mm from the end of the glass ribbon G2 towards the center in the widthwise direction.

[0037] On the other hand, the viscosity of the widthwise ends G2B, G2B of the glass ribbon G2 on the molten metal surface is 10 4.9 (dPa·sec) position and 10 6.1 It is preferable to control the heating temperature of the G2B, G2B at both ends in the width direction so that the distance to the position with (dPa·sec) is 30m or less. If it is 30m or less, the glass ribbon can be cooled sufficiently. The aforementioned distance may be 25m or less, or 20m or less.

[0038] Furthermore, a top roll 23 is placed on the upper surface of both ends G2B, G2B in the width direction of the glass ribbon G2 heated by the heater 24, and the glass ribbon is shaped to the desired width, thickness, and shape by the action of this top roll 23. At this time, it is preferable that the peripheral speed of each top roll 23 is adjusted so that the one located downstream is faster. Also, when manufacturing the convex glass 100, it is preferable to rotate multiple top rolls 23 such that the peripheral speed of the top roll 23A upstream in the direction of travel X of the glass ribbon G2 is slower than the peripheral speed of the top roll 23B downstream. In addition, by substantially not using the central heater 24A and heating only with the end heaters 24B, the viscosity of both ends G2B, G2B in the width direction of the glass ribbon does not increase as much as the central part G2A in the width direction. As a result, when widening the width of the glass ribbon G2 that spreads out on both sides of the rotation axis of the upstream top roll 23A, the ends G2B, G2B in the width direction of the glass ribbon G2 can be made thinner, and the central part G2A in the width direction can be made thicker.

[0039] The upstream top rolls 23A refer to the top rolls 23 closest to the melting furnace 11 among the multiple pairs of top rolls 23 positioned at both ends G2B, G2B in the width direction of the glass ribbon G2 advancing in the molten metal bath 21. There may be only one pair closest to the melting furnace 11, or two pairs or three pairs close to the melting furnace 11. Preferably, there are two pairs. In particular, the pair of top rolls 23 closest to the melting furnace 11 is called the upstream top rolls 23A. The downstream top rolls 23B refer to the top rolls 23 closest to the annealing chamber 31. There may be only one pair closest to the annealing chamber 31, or two pairs or three pairs close to the annealing chamber 31. In particular, the pair of top rolls 23 closest to the annealing chamber 31 is called the downstream top rolls 23B. Figures 1(A) and (B) illustrate an example where there are two pairs of upstream top rolls 23A and two pairs of downstream top rolls 23B.

[0040] It is preferable to arrange 7 to 15 pairs of top rolls 23 at both ends G2B, G2B in the width direction of the glass ribbon G2. If there are 7 to 15 pairs, it becomes easier to adjust the glass ribbon G2 to a predetermined thickness. It is more preferable to arrange 8 to 13 pairs of top rolls 23. In addition, FIGS. 1(A) and (B) illustrate an example in which 9 pairs of top rolls 23 are arranged at both ends G2B, G2B in the width direction of the glass ribbon G2.

[0041] Also, in the region where the viscosity of both ends G2B, G2B in the width direction of the glass ribbon G2 on the molten metal surface is 10 5.3 (dPa·sec) or less (hereinafter referred to as the low viscosity region), the number of top rolls 23 arranged at both ends G2B, G2B in the width direction may be 8 pairs or less, 7 pairs or less, 6 pairs or less, 5 or less, or 3 pairs or less.

[0042] On the other hand, in the region where the viscosity of both ends G2B, G2B in the width direction of the glass ribbon G2 on the molten metal surface is more than 10 5.3 (dPa·sec) (hereinafter referred to as the high viscosity region), the number of top rolls 23 arranged at both ends G2B, G2B in the width direction may be 10 pairs or less, 8 pairs or less, 6 pairs or less, 4 or less, 2 pairs or less, or 1 pair or less.

[0043] The upstream top roll 23A may be arranged in the low viscosity region, and the downstream top roll 23B may be arranged in the high viscosity region.

[0044] In the top roll 23 arranged in the region where the viscosity of both ends G2B, G2B in the width direction of the glass ribbon G2 on the molten metal surface is 10 5.3 (dPa·sec) or less (low viscosity region), the difference in peripheral speed between at least one pair of adjacent top rolls 23, 23 in the traveling direction X is preferably 35 (m / hour) or more. If it is 35 (m / hour) or more, the viscosity of the glass ribbon G2 is 10 5.3In the region where the pressure is less than (dPa·sec), the glass ribbon G2 is pulled downstream in the X2 direction, making the ends G2B, G2B in the width direction thinner. As a result, the ends G2B, G2B in the width direction are thin, and the central part G2A in the width direction is thicker, thus producing a glass plate with a convex cross-section in the width direction Y.

[0045] The viscosity of the widthwise ends G2B, G2B of the glass ribbon G2 in the molten metal bath 21 is 10 5.3 In the region where the pressure is less than or equal to (dPa·sec), the difference in peripheral speed between at least one pair of adjacent top rolls 23, 23 in the direction of travel X may be 40 m / h or more, 45 m / h or more, or 50 m / h or more.

[0046] On the other hand, the viscosity of the widthwise ends G2B, G2B of the glass ribbon G2 on the molten metal surface is 10 5.3 In a top roll 23 located in a region with a viscosity of (dPa·sec) or less (low viscosity region), it is preferable that the difference in peripheral speed between at least one pair of adjacent top rolls 23, 23 in the direction of travel X is 100 m / h or less. If it is 100 m / h or less, it is easier to adjust the thickness of the glass ribbon G2. It may also be 80 m / h or less, or 60 m / h or less.

[0047] The peripheral speed R of the uppermost top roll 23A is preferably 120 m / h or less. If it is 120 m / h or less, the width of the glass ribbon G2 that spreads out on both sides of the rotation axis of the uppermost pair of top rolls 23A can be increased. As a result, the ends G2B, G2B in the width direction of the glass ribbon G2 tend to be thin, while the central part G2A in the width direction tends to be thicker. The peripheral speed R of the uppermost top roll 23A may be 110 m / h or less, 100 m / h or less, 90 m / h or less, 80 m / h or less, 70 m / h or less, or 60 m / h or less.

[0048] On the other hand, the peripheral speed R of the uppermost top roll 23A is preferably 30 m / hour or higher. A peripheral speed of 30 m / hour or higher makes it easier to adjust the thickness of the glass ribbon G2. The peripheral speed R of the uppermost top roll 23A may be 40 m / hour or higher, or even 50 m / hour or higher.

[0049] Figure 4 is an enlarged view of the top roll 23. As shown in Figure 4, the angle D between the direction of travel X of the glass ribbon G2 and the rotation axis J of the top roll 23 may be adjusted to adjust the thickness of the glass ribbon G2. By adjusting the angle D of the uppermost top roll 23A to 75° to 90° and the angle D of the lowermost top roll 23B to 90° to 105°, it is easier to reduce the thickness of the widthwise ends G2B, G2B of the glass ribbon G2. The angle D of the uppermost top roll 23A is more preferably 80° to 85°, and even more preferably 81° to 84°. The angle D of the lowermost top roll 23B is more preferably 95° to 100°, and even more preferably 96° to 99°.

[0050] Furthermore, by adjusting the advance speed of the glass ribbon G2 in the molding section 20 and the annealing section 30, it becomes easier to spread the glass ribbon G2 in the width direction Y upstream of the molten metal bath 21, and the thickness of the widthwise ends G2B, G2B of the glass ribbon G2 can be reduced.

[0051] The advance speed of the glass ribbon G2 in the molding section 20 and the annealing section 30 may be 200 to 1500 m / hours. Setting the advance speed of the glass ribbon G2 in the molding section 20 and the annealing section 30 to 200 to 1500 m / hours makes it easier to spread the glass ribbon G2 in the width direction Y upstream of the molten metal bath 21, and makes it easier to reduce the thickness of the width direction ends G2B, G2B of the glass ribbon G2. The advance speed of the glass ribbon G2 may be 500 m / hours or more, 600 m / hours or more, or 700 m / hours or more. On the other hand, the advance speed of the glass ribbon G2 may be 1300 m / hours or less, 1100 m / hours or less, or 900 m / hours or less.

[0052] The difference (TM) between the maximum value T and the minimum value M of the thickness of the glass plate manufactured by the manufacturing method according to one embodiment of the present invention is preferably 0.1 mm or more. If the difference (TM) is 0.1 mm or more, the occurrence of double images can be reduced when used as information display glass, even when installed in a vehicle with a large angle of the windshield to the horizontal plane. Here, the difference (TM) between the maximum value T and the minimum value M of the thickness of the glass plate is the difference between the maximum and minimum values ​​of the thickness of the convex glass 100 obtained by cutting and removing both ends in the width direction Y of the glass ribbon G2, which is distorted by the top roll 23, using a cutting machine. The difference (TM) may be 0.2 mm or more, 0.3 mm or more, 0.4 mm or more, or 0.5 mm or more. On the other hand, the difference (TM) may be 1.5 mm or less. If it is 1.5 mm or less, distortion of the reflected image can be suppressed when used as information display glass, even when installed in a vehicle with a small angle of the windshield to the horizontal plane. The difference (TM) may be 1.3 mm or less, 1.2 mm or less, 1.1 mm or less, or 1.0 mm or less. When this glass plate is used, for example, as a windshield for an automobile, the difference (TM) between the maximum value T and minimum value M of the glass plate thickness is selected depending on the angle at which the windshield is mounted and the angle and position of the illuminator for displaying information.

[0053] The sheet glass produced by the manufacturing method according to an embodiment of the present invention preferably has a maximum height Rz of the roughness curve at a reference length of 25 mm specified in JIS B 0601:2001 on the main surface of the sheet glass of 0.3 μm or less. If the Rz of the main surface of the sheet glass is 0.3 μm or less, for example, when the sheet glass is used as glass for information display, the view seen through the glass appears without distortion. In addition, the reflected image when information is displayed on the sheet glass is less likely to be distorted. Here, the roughness curve is represented by a shape waveform. Rz is more preferably 0.25 μm or less, further preferably 0.2 μm or less, particularly preferably 0.18 μm or less, and most preferably 0.16 μm or less. The Rz of the main surface of the sheet glass can be reduced by slowing down the traveling speed V of the glass ribbon G2 in the annealing section 30. Here, the main surface of the sheet glass is the surface where the glass ribbon G2 was in contact with the molten metal 22 in the molten metal bath 21 (hereinafter referred to as the molten metal contact surface), and the surface that was not in contact with the molten metal 22 facing the molten metal contact surface (hereinafter referred to as the molten metal non-contact surface).

[0054] As shown in FIG. 1(B), the ratio W / N of the distance W (the distance between the two first walls 27B, 27B) between the two side walls 27, 27 in the upstream region of the shoulder 27A of the molten metal bath 21 and the distance N (the distance between the two second walls 27C, 27C) between the two side walls 27, 27 in the downstream region of the shoulder 27A of the molten metal bath 21 is preferably greater than 1.0 and not more than 1.6 (1.0 < W / N ≤ 1.6). If W / N is not more than 1.6, the area of the portion of the molten metal 22 not covered by the glass ribbon G2 in the upstream region of the shoulder 27A decreases, so the flow of the molten metal 22 in the upstream direction X1 is less likely to occur, and the reciprocating movement (swing) of the glass ribbon G2 in the width direction Y is less likely to occur. Therefore, the variation in the wedge angle β of the wedge-shaped glass 200 (see FIG. 2(B)) obtained by cutting the convex glass 100 (see FIG. 2(A)) obtained by the manufacturing method of the sheet glass of the present embodiment can be suppressed.

[0055] If the ratio W / N is greater than 1.0, the distance between the two side walls 27, 27 in the downstream region of the shoulder 27A can be narrowed, and the amount of the molten metal 22 in the molten metal bath 21 can be reduced.

[0056] The W / N ratio is more preferably 1.1 or higher, and even more preferably 1.3 or higher. Furthermore, the W / N ratio is more preferably 1.55 or lower, and even more preferably 1.50 or lower.

[0057] It is preferable that the glass ribbon G2 is heated by the heater 24 such that, at a position 20% from the upstream wall 25 (0.2L downstream X2 from the upstream wall 25) with respect to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)), the viscosity of the central part G2A in the width direction of the glass ribbon G2 on the molten metal surface is 10^(4.5) (dPa·sec) or more. If the viscosity of the central part G2A in the width direction is 10^(4.5) (dPa·sec) or more, the ends G2B, G2B in the width direction tend to be thin, and the central part G2A in the width direction tends to be thick. Therefore, the wedge angle β of the wedge-shaped glass 200 (see Figure 2(B)) obtained by cutting the convex glass 100 (see Figure 2(A)) obtained by the manufacturing method of plate glass of this embodiment can be increased.

[0058] The viscosity of the central portion G2A of the glass ribbon G2 in the width direction on the molten metal surface at a position 20% from the upstream wall 25 (0.2L downstream X2 from the upstream wall 25) is more preferably 10^(5.0) (dPa·sec) or higher, and even more preferably 10^(5.3) (dPa·sec) or higher. This is because the temperature of the central portion G2A of the glass ribbon G2 in the width direction is relatively lower than the temperatures of the ends G2B, G2B in the width direction, allowing the wedge angle β to be increased.

[0059] It is preferable that the glass ribbon G2 is heated by the heater 24 such that, at a position 20% from the upstream wall 25 (0.2L downstream X2 from the upstream wall 25) with respect to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)), the viscosity of the central part G2A in the width direction of the glass ribbon G2 on the molten metal surface is 10^(6.0) (dPa·sec) or less. If the viscosity of the glass ribbon G2 is too high, the top roll 23 will have difficulty entering the glass ribbon G2, making it difficult to control the position of the glass ribbon G2, and thus reciprocating motion (swing) in the width direction will easily occur. In this embodiment, since the viscosity of the central part G2A in the width direction is 10^(6.0) (dPa·sec) or less, the occurrence of swing can be suppressed.

[0060] The viscosity of the central portion G2A of the glass ribbon G2 in the width direction on the molten metal surface at a position 20% from the upstream wall 25 (0.2L downstream X2 from the upstream wall 25) is more preferably 10^(5.8) (dPa·sec) or less, and even more preferably 10^(5.6) (dPa·sec) or less. This is because the lower the viscosity of the glass ribbon G2, the easier it is for the top roll 23 to enter the glass ribbon G2, thereby suppressing the occurrence of swing.

[0061] With respect to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)), it is preferable that the difference in temperature I between the widthwise central part G2A of the glass ribbon G2 on the molten metal surface and the widthwise ends K of the molten metal 22 at a position 32% from the upstream wall 25 (0.32L downstream in the X2 direction from the upstream wall 25) is 62°C or less. If the temperature difference (IK) is 62°C or less, the difference in viscosity between the widthwise ends and the widthwise central part of the glass ribbon G2 becomes small, and the widthwise ends G2B, G2B tend to be thin, while the widthwise central part G2A tends to be thick. The temperature difference (IK) is more preferably 50°C or less, and even more preferably 40°C or less. The lower limit of the temperature difference (IK) may be 0°C or higher, 10°C or higher, or 15°C or higher in order to suppress excessive output to the heater 24. Note that the temperature K at both ends of the molten metal 22 in the width direction refers to the temperature at a position 50 mm from the center in the width direction from each of the two side walls 27, 27 of the molten metal bath 21.

[0062] It is preferable that the glass ribbon G2 is heated by the heater 24 such that, at a position 32% from the upstream wall 25 (0.32L downstream X2 from the upstream wall 25) with respect to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)), the viscosity of the central part G2A in the width direction of the glass ribbon G2 on the molten metal surface is 10^(4.7) (dPa·sec) or more. If the viscosity of the central part G2A in the width direction is 10^(4.7) (dPa·sec) or more, the ends G2B, G2B in the width direction tend to be thin, and the central part G2A in the width direction tends to be thick. Therefore, the wedge angle β of the wedge-shaped glass 200 (see Figure 2(B)) obtained by cutting the convex glass 100 (see Figure 2(A)) obtained by the manufacturing method of plate glass of this embodiment can be increased.

[0063] At a position 32% from the upstream wall 25 (0.32L downstream in X2 from the upstream wall 25), the viscosity of the central part G2A of the glass ribbon G2 on the molten metal surface is more preferably 10^(5.0) (dPa·sec) or higher, and even more preferably 10^(5.3) (dPa·sec) or higher. This is because the temperature of the central part G2A of the glass ribbon G2 in the width direction is lower than the temperature of the ends G2B, G2B in the width direction, allowing the wedge angle β to be increased.

[0064] It is preferable that the glass ribbon G2 is heated by the heater 24 such that, at a position 32% from the upstream wall 25 (0.32L downstream X2 from the upstream wall 25) with respect to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)), the viscosity of the central part G2A in the width direction of the glass ribbon G2 on the molten metal surface is 10^(6.3) (dPa·sec) or less. If the viscosity of the glass ribbon G2 is too high, the top roll 23 will have difficulty entering the glass ribbon G2, making it difficult to control the position of the glass ribbon G2, and thus reciprocating motion (swinging) in the width direction will easily occur. In this embodiment, since the viscosity of the central part G2A in the width direction is 10^(6.3) (dPa·sec) or less, the occurrence of swinging can be suppressed.

[0065] The viscosity of the central part G2A of the glass ribbon G2 in the width direction on the molten metal surface at a position 32% from the upstream wall 25 (0.32L downstream X2 from the upstream wall 25) is more preferably 10^(6.0) (dPa·sec) or less, and even more preferably 10^(5.8) (dPa·sec) or less. This is because the lower the viscosity of the glass ribbon G2, the easier it is for the top roll 23 to enter the glass ribbon G2, thereby suppressing the occurrence of swing.

[0066] It is preferable that the ratio c / b of the maximum width c of the glass ribbon G2 in the width direction Y (located between the upstream wall 25 and the downstream wall 26) and the length b of the glass ribbon G2 in the width direction Y at the downstream end of the molten metal bath 21 is 1.4 to 2.2 (1.4 ≤ c / b ≤ 2.2). If the ratio c / b is 1.4 to 2.2, the area of ​​the molten metal 22 that is not covered by the glass ribbon G2 decreases, making it difficult for the molten metal 22 to flow upstream X1, and making it difficult for the glass ribbon G2 to move back and forth (swing) in the width direction Y.

[0067] Furthermore, the ratio c / b is more preferably 1.6 or higher, and even more preferably 1.7 or higher. The ratio c / b is more preferably 2.1 or lower, and even more preferably 2.0 or lower. The widthwise length of the glass ribbon G2 in the molten metal bath 21 is determined from the image obtained by photographing the glass ribbon G2 with a camera and the position of the top roll.

[0068] With respect to the length L from the upstream wall 25 to the downstream wall 26, the ratio a / b of the width a (not shown) of the glass ribbon G2 at a position 35% from the upstream wall 25 (0.35L downstream from the upstream wall 25 in the X2 direction) and the length b (not shown) of the glass ribbon G2 in the width direction Y at the downstreammost point of the molten metal bath 21 is preferably 1.0 to 1.9 (1.0 ≤ a / b ≤ 1.9). If the ratio a / b is 1.0 to 1.9, the area of ​​the molten metal 22 that is not covered by the glass ribbon G2 decreases, making it difficult for the molten metal 22 to flow upstream in the X1 direction, and making it difficult for the glass ribbon G2 to move back and forth (swing) in the width direction Y.

[0069] Furthermore, the ratio a / b is more preferably 1.3 or higher, and even more preferably 1.4 or higher. The ratio a / b is more preferably 1.8 or lower, even more preferably 1.7 or lower, and particularly preferably 1.6 or lower.

[0070] With respect to the length L from the upstream wall 25 to the downstream wall 26, it is preferable that the ratio A / B of the length A (not shown) in the width direction Y of the glass ribbon G2 to the length B (not shown) in the width direction Y of the molten metal surface not covered by the glass ribbon G2 is between 4 and 11 (4 ≤ A / B ≤ 11). Length B is the length in the width direction Y of the molten metal on both sides of the glass ribbon G2 at the 20% position from the upstream wall 25 (0.2L in the downstream direction X2 from the upstream wall 25). Therefore, length B is obtained by subtracting length A from the distance W (see Figure 1(B)) between the two side walls 27, 27 in the region upstream of the shoulder 27A of the molten metal bath 21 (B = WA). In this way, since the ratio A / B is set to 4 to 11, the molten metal 22 is covered by the glass ribbon G2 over a wide area, making it difficult for the molten metal 22 to flow upstream X1, and suppressing the reciprocating motion (swing) of the glass ribbon G2 in the width direction Y. The length B is determined from an image obtained by photographing the molten metal surface not covered by the glass ribbon G2 with a camera.

[0071] Furthermore, if the ratio A / B is less than 4, the exposed area of ​​the molten metal 22 widens, making it easier for the glass ribbon G2 to swing. Also, if the ratio A / B is greater than 11, the width of the glass ribbon G2 widens relative to the molten metal bath 21, making it difficult to control the width of the glass ribbon G2 with the top roll 23, and making it easier for it to interfere with components installed in the molten metal bath 21. For this reason, it is preferable to keep the ratio A / B at 11 or less. Moreover, it is more preferable for the ratio A / B to be 5 or more, and even more preferable for it to be 5.5 or more. It is more preferable for the ratio A / B to be 10 or less, and even more preferable for it to be 9 or less.

[0072] Wedge-shaped glass and laminated glass are manufactured using the plate glass produced by the plate glass manufacturing method described above. A method for manufacturing wedge-shaped glass and laminated glass according to one embodiment of the present invention will be described with reference to Figures 2(A)-(B) and 3(A)-(C). Here, a method for manufacturing laminated glass used in vehicle windshields will be used as an example.

[0073] A method for manufacturing wedge-shaped glass according to one embodiment of the present invention includes the step of cutting a convex-shaped plate glass 100 obtained by the plate glass manufacturing method described above to obtain wedge-shaped glass 200. A method for manufacturing laminated glass according to one embodiment of the present invention includes the step of cutting a convex-shaped plate glass 100 obtained by the plate glass manufacturing method described above to obtain wedge-shaped glass 200, and the step of laminating and pressing the wedge-shaped glass 200 and other plate glass with an interlayer in between.

[0074] First, by the above-described method for manufacturing flat glass, a convex glass 100 is obtained that becomes thicker towards the center in the width direction (see Figure 2(A)). By cutting this convex glass 100 at a predetermined position (part A in the figure), a wedge-shaped glass 200 is obtained in which one end is thicker than the other end in the width direction (see Figure 2(B)). The cutting method is not limited, but for example, the convex glass 100 can be cut out by forming scribe lines in the shape of a window glass with a cutter and then breaking it, thereby obtaining the wedge-shaped glass 200. The edges of the wedge-shaped glass 200 are then chamfered.

[0075] Next, the pair of wedge-shaped glass 200 and other flat glass sheets are stacked with a release agent in between and bent by methods such as gravity bending. The pair of flat glass sheets are heated in a furnace, softened, bent, and then slowly cooled. Note that the bending method is not limited to gravity bending; the pair of flat glass sheets may be formed by press bending, or they may be bent one by one without being stacked.

[0076] Next, laminated glass is obtained by laminating the wedge-shaped glass 200 and other flat glass with an interlayer in between and pressing them together. The other flat glass may be the wedge-shaped glass 200 or a flat glass of uniform thickness. The flat glass of uniform thickness is obtained by a known method and cut by the cutting method described above. Laminated glass 300 in which the other flat glass is the wedge-shaped glass 200 (see Figures 3(A) and (B)) is installed in a vehicle with a large angle of the windshield to the horizontal plane, and the reflected image when displaying information is less distorted. Laminated glass 400 in which the other flat glass is a flat glass of uniform thickness (see Figure 3(C)) allows the view seen through the windshield to appear without distortion. Examples of materials for the interlayer include polyvinyl butyral.

[0077] When bonding, the pair of glass plates and the interlayer are first degassed to remove air between them, and then heated to bond them together. For example, the air can be removed by placing the assembled pair of glass plates and the interlayer in a rubber bag and heating it under reduced pressure. Alternatively, the nipper-top roll method or the rubber channel method may be used. Next, the assembled pair of glass plates and the interlayer are subjected to pressure treatment in an autoclave to heat and bond them together. As the interlayer, for example, polyvinyl butyral (PVB) or ethylene vinyl acetate (EVA) can be used.

[0078] Next, we will describe a wedge-shaped glass according to one embodiment of the present invention. Figures 5(A) and 5(B) show a wedge-shaped glass 500 according to one embodiment of the present invention, where Figure 5(A) is a plan view and Figure 5(B) is a cross-sectional view.

[0079] A wedge-shaped glass 500 according to one embodiment of the present invention can be obtained, for example, by cutting a plate glass obtained by the plate glass manufacturing method described above. The cutting method is not limited, but for example, a wedge-shaped glass 500 according to one embodiment of the present invention can be obtained by forming scribe lines in the shape of a window glass on the plate glass with a cutter and then breaking it.

[0080] When the wedge-shaped glass 500 according to one embodiment of the present invention is used as the windshield of a vehicle, the wedge-shaped glass 500 is installed in the vehicle such that, for example, the side 502 with the minimum thickness is located at the bottom, and information is displayed at the bottom of the windshield where the thickness is small.

[0081] A wedge-shaped glass 500 according to one embodiment of the present invention is characterized in that at least one main surface is a convex surface 507. Because the main surface is a convex surface 507, the reflected image when information is displayed on the glass plate is less likely to be distorted. Furthermore, compared to the case where the main surface is concave, the thickness of the upper part of the windshield where no information is displayed is reduced, allowing for a lighter windshield and improved vehicle fuel efficiency. The position where information is displayed on the windshield is not limited to the lower part; it may be at the top, to the left or right, or in the center. The glass plate is installed so that the thickness of the area where information is displayed is reduced. Regardless of the position where information is displayed, if the main surface is a convex surface 507, the thickness of the portion where no information is displayed can be reduced compared to the case where the main surface is concave, thus reducing the weight of the windshield.

[0082] The wedge-shaped glass 500 according to one embodiment of the present invention is preferably rectangular. If the wedge-shaped glass 500 is rectangular, handling such as transportation is easier. Here, the term "rectangle" does not mean a perfect rectangle; the sides may be curved. Also, the angle of the corners is not limited to 90°; it may be between 80 and 100°.

[0083] The wedge-shaped glass 500 according to one embodiment of the present invention may have notches and its corners may be arc-shaped.

[0084] In one embodiment of the present invention, the wedge-shaped glass 500 passes through the centroid G of the convex surface 507 and connects two opposing sides of the four sides 501, 502, 508, and 509 of the convex surface 507 by the shortest distance. Of the intersection points 504 and 505 of the line segment 503 and the sides of the convex surface 507, the point where the thickness of the wedge-shaped glass 500 in the vertical direction is smaller when the wedge-shaped glass 500 is placed on a horizontal surface is designated as the first point 504, and the point on the convex surface 507 located at a distance of 2 / 5 of the length of the line segment 503 from the first point 504 is designated as the second point 506. Preferably, the angle α between the straight line H connecting the first point 504 and the second point 506 and the horizontal plane is 0.020° to 0.050°. The thickness of the glass plate is determined, for example, by a laser displacement meter, microgauge, ultrasonic thickness gauge, etc., and the angle α is calculated from the measured thickness.

[0085] When the windshield is installed in a vehicle where the angle of the windshield with respect to the horizontal plane is small, a smaller angle α of the wedge-shaped glass 500 is preferable because it reduces the double image of the projected image projected onto the windshield. On the other hand, when the windshield is installed in a vehicle where the angle of the windshield with respect to the horizontal plane is large, a larger angle α of the wedge-shaped glass 500 is preferable because it reduces the double image of the projected image projected onto the windshield.

[0086] The wedge-shaped glass 500 according to one embodiment of the present invention reduces double images when information is displayed on a flat glass surface when mounted on a vehicle with a large angle of the windshield relative to the horizontal plane, by having an angle α of 0.020° or more. The angle α may also be 0.023° or more, 0.025° or more, 0.030° or more, or 0.033° or more. Furthermore, by having an angle α of 0.050° or less, double images are reduced when information is displayed on a flat glass surface even when mounted on a vehicle with a small angle of the windshield relative to the horizontal plane. The angle α may also be 0.04° or less. The optimal angle α is selected depending on the angle at which the windshield is mounted and the mounting angle and position of the illuminator for displaying the information.

[0087] In one embodiment of the present invention, the wedge-shaped glass 500 preferably has a maximum height Rz of 0.3 μm or less of the roughness curve at a standard length of 25 mm as specified in JIS B 0601:2001 for the main surface of the wedge-shaped glass 500. Because Rz is 0.3 μm or less, the view seen through the wedge-shaped glass 500 appears without distortion. In addition, the reflected image when information is displayed on the glass plate is less likely to be distorted.

[0088] In one embodiment of the present invention, the wedge-shaped glass 500 preferably has a difference (TM) of 0.1 mm or more between the maximum value T and the minimum value M of the thickness of the wedge-shaped glass 500. Because the difference (TM) between the maximum value T and the minimum value M of the thickness of the plate glass is 0.1 mm or more, the occurrence of double images can be suppressed when it is installed in a vehicle with a large angle of the windshield with respect to the horizontal plane and used as information display glass. On the other hand, the difference (TM) may be 1.5 mm or less. If it is 1.5 mm or less, the occurrence of double images can be suppressed when it is installed in a vehicle with a small angle of the windshield with respect to the horizontal plane and used as information display glass. The difference (TM) may be 1.3 mm or less, 1.2 mm or less, 1.1 mm or less, or 1.0 mm or less.

[0089] In one embodiment of the present invention, the wedge-shaped glass 500 preferably has a ratio T / M of 1.10 to 1.40 between the maximum and minimum thickness T of the wedge-shaped glass 500. If T / M is 1.10 or higher, the occurrence of double images can be suppressed when the windshield is mounted on a vehicle with a large angle to the horizontal plane and information is displayed on the glass. The ratio T / M may be 1.12 or higher, 1.15 or higher, 1.20 or higher, or 1.25 or higher. Furthermore, if the ratio T / M is 1.40 or lower, the occurrence of reflected images can be suppressed when information is displayed on the glass, even when mounted on a vehicle with a small angle to the horizontal plane of the windshield. The ratio T / M may be 1.35 or lower, 1.30 or lower, or 1.28 or lower. The optimal ratio T / M is selected depending on the angle at which the windshield is mounted and the mounting angle and position of the illuminator for displaying information.

[0090] In one embodiment of the present invention, the wedge-shaped glass 500 preferably has short sides 508 and 509 of 600 mm or more. If it is 600 mm or more, it can be used in large vehicles. It can also be installed in vehicles where the angle of the windshield with respect to the horizontal plane is small. The plate glass may be 800 mm or more, 1000 mm or more, 1200 mm or more, or 1400 mm or more.

[0091] Laminated glass can be manufactured using wedge-shaped glass 500. A method for manufacturing laminated glass according to one embodiment of the present invention includes the step of cutting a plate glass 100 to obtain wedge-shaped glass. A method for manufacturing laminated glass according to one embodiment of the present invention includes the step of cutting a plate glass 100 to obtain wedge-shaped glass, and the step of laminating and pressing the wedge-shaped glass and other plate glass with an interlayer in between.

[0092] First, by cutting the glass plate 100 at a predetermined position, a wedge-shaped glass is obtained in which one end is thicker than the other in the width direction. Then, laminated glass is manufactured by following the same process as the manufacturing method for laminated glass using the glass plate manufactured by the glass plate manufacturing method described above.

[0093] As described above, in the above embodiment, the ends G2B, G2B in the width direction of the glass ribbon are heated more strongly than the central part G2A in the width direction in the upstream region of the molten metal bath 21, and the multiple top rolls 23 are rotated such that the peripheral speed of the upstream top roll 23A in the direction of travel F1 is slower than the peripheral speed of the downstream top roll 23B. As a result, the viscosity of the ends G2B, G2B in the width direction does not increase as much as that of the central part G2A in the width direction, and the width of the glass ribbon spreading out on both sides of the rotation axis of the upstream top roll can be widened, making it easier to spread the glass ribbon G2 in the width direction upstream of the molten metal bath 21, and the thickness of the ends G2B, G2B in the width direction of the glass ribbon G2 can be made thinner and the central part G2A in the width direction thicker.

[0094] Also, since the ratio W / N of the distance W (the distance between the two first walls 27B, 27B) between the two side walls 27, 27 in the upstream region from the shoulder 27A of the molten metal bath 21 to the distance N (the distance between the two second walls 27C, 27C) between the two side walls 27, 27 in the downstream region from the shoulder 27A of the molten metal bath 21 is set to be greater than 1.0 and less than or equal to 1.6, the flow of the molten metal 22 in the upstream direction X1 is less likely to occur, and the reciprocating movement (swing) of the glass ribbon G2 in the width direction Y is less likely to occur. Therefore, variations in the wedge angle of the wedge-shaped glass obtained by cutting the sheet glass obtained by the method for manufacturing sheet glass of the present embodiment can be suppressed.

Example

[0095] Next, examples of the present invention will be described. Using the glass manufacturing apparatus 1 shown in FIGS. 1(A) and (B), convex glasses 100 according to Examples 1 to 15 were manufactured. Examples 1 to 14 are examples, and Example 15 is a comparative example.

[0096] In Examples 1 to 15, the distance W (the distance between the two first walls 27B, 27B) between the two side walls 27, 27 in the upstream region from the shoulder 27A of the molten metal bath 21, the distance N (the distance between the two second walls 27C, 27C) between the two side walls 27, 27 in the downstream region from the shoulder 27A of the molten metal bath 21, and their ratio W / N were as shown in Table 1. Examples 1 to 14 satisfy the above-described formula "1.0 < W / N ≦ 1.6", but Example 15 does not satisfy the above formula.

[0097] In Examples 1 to 15, the position where the first wall 27B is connected to the shoulder 27A was at the ratio shown in Table 1 with respect to the length L (see FIG. 1(B)) from the upstream wall 25 to the downstream wall 26. Examples 1 to 15 satisfied the above-described condition "at the position of 60% to 75% from the upstream wall 25".

[0098] In Examples 1-15, the connection point between shoulder 27A and the second wall 27C was at a position relative to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)), as shown in Table 1. Examples 1-15 satisfied the above-mentioned condition "65% to 85% from the upstream wall 25".

[0099] In Examples 1 to 15, the temperature and viscosity of the central part G2A in the width direction of the glass ribbon G2 on the molten metal surface at a position 20% from the upstream wall 25 (0.2L downstream in the X2 direction from the upstream wall 25) relative to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)) were as shown in Table 1. Examples 1 to 15 satisfied the above-mentioned condition "viscosity of 10^(4.5) (dPa·sec) or more". Also, Examples 1 to 15 satisfied the above-mentioned condition "viscosity of 10^(6.0) (dPa·sec) or less".

[0100] In Examples 1 to 15, the temperature I and viscosity of the central part G2A in the width direction of the glass ribbon G2 on the molten metal surface at a position 32% from the upstream wall 25 (0.32L downstream in the X2 direction from the upstream wall 25) with respect to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)) were as shown in Table 1. Examples 1 to 15 satisfied the above-mentioned condition "viscosity of 10^(4.7) (dPa·sec) or more". Also, Examples 1 to 15 satisfied the above-mentioned condition "viscosity of 10^(6.3) (dPa·sec) or less".

[0101] In Examples 1 to 15, the temperatures K at both ends of the molten metal 22 in the width direction at a position 32% from the upstream wall 25 (0.32L downstream in X2 from the upstream wall 25) relative to the length L from the upstream wall 25 to the downstream wall 26 (see Figure 1(B)) were as shown in Table 1. The difference between the above-mentioned temperature I and temperature K (IK) was also as shown in Table 1. Examples 1 to 14 satisfied the above-mentioned condition "(IK) is 62°C or less".

[0102] In Examples 1 to 14, the maximum width c of the glass ribbon G2 in the width direction Y in the molten metal bath 21, the width b at the downstream end, and their ratio c / b were as shown in Table 1. Examples 1 to 14 satisfied the above-mentioned condition "1.4 ≤ c / b ≤ 2.2".

[0103] In Examples 1 to 14, the width a of the glass ribbon G2 at a position 35% from the upstream wall 25 (0.35L downstream in the X2 direction from the upstream wall 25) relative to the length L from the upstream wall 25 to the downstream wall 26, the minimum width b of the glass ribbon G2 in the width direction Y in the molten metal bath 21, and their ratio a / b are as shown in Table 1. Examples 1 to 14 satisfied the above-mentioned condition "1.0 ≤ a / b ≤ 1.9".

[0104] In Examples 1 to 14, with respect to the length L from the upstream wall 25 to the downstream wall 26, at a position 20% from the upstream wall 25 (0.2L downstream in the X2 direction from the upstream wall 25), the length A (not shown) in the width direction Y of the glass ribbon G2, the length B (not shown) in the width direction Y of the molten metal surface not covered by the glass ribbon G2, and their ratio A / B were as shown in Table 1. Examples 1 to 14 satisfied the above-mentioned condition "4 ≤ A / B ≤ 11".

[0105] [Table 1]

[0106] In Examples 1 to 15, top rolls 23 were placed at both ends of the molten metal bath 21 in the width direction Y. The advance speed V (m / h) of the glass ribbon G2 in the annealing section 30 was set as shown in Table 2.

[0107] Table 2 also shows the maximum T (mm) and minimum M (mm) thickness of the glass plate (convex glass) obtained under the above manufacturing conditions, as well as the thickness t, difference (TM) (mm), and ratio T / M of the central part G2A in the width direction of the glass ribbon G2 in the annealing section 30.

[0108] [Table 2]

[0109] The angles α (see Figure 5(B)) of the convex glass obtained under the above manufacturing conditions for Examples 1 to 15 were as shown in Table 1. In all Examples 1 to 14 except for Example 15, the angle α was within the preferred range of 0.020° to 0.050°.

[0110] In all examples 1-15, the maximum distance (swing width) traveled in the Y direction over 30 minutes at the point where the glass ribbon G2 is cut was less than 1.5 inches, keeping it at a small value. However, in example 15, when the maximum distance (swing width) traveled in the Y direction over 30 minutes at the point where the glass ribbon G2 is cut was kept below 1.5 inches, the angle α became 0.017°, and it was not possible to make the angle α greater than or equal to 0.020°. If an attempt were made to manufacture a convex glass with an angle α greater than or equal to 0.020° in example 15, the viscosity of the glass ribbon G2 would need to be increased, resulting in a larger swing width of 2.0 inches or more.

[0111] Although the method for manufacturing convex plate glass of the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements are possible without departing from the spirit of the present invention.

[0112] In the melting section 10, the glass raw material is melted into molten glass G1 in the melting furnace 11. However, it is preferable to remove stainless steel contained in the glass raw material using a metal detector before introducing it into the melting furnace 11. Stainless steel contains iron, nickel, chromium, etc. Conventional metal detectors can distinguish between metals and nonmetals, but they cannot arbitrarily distinguish only stainless steel. Therefore, if stainless steel is removed from the glass raw material, the iron necessary for melting the glass raw material is also removed. The metal detector used to remove stainless steel has one coil and distinguishes between stainless steel and iron by the magnetic field generated by the coil. Iron is magnetized by the alternating magnetic field emitted from the transmitting coil. Magnetic field lines are attracted to the iron, and by detecting this with a differential receiving coil, the iron is detected. In addition, eddy currents are generated in the stainless steel by the alternating magnetic field emitted from the transmitting coil, and a magnetic field is generated near the stainless steel. By detecting this change in magnetic field with a differential receiving coil, the stainless steel is detected. The phase of eddy currents generated in stainless steel lags by approximately 90° compared to the phase of the transmitting coil, allowing for the distinction between stainless steel and iron by detecting the phase angle. The phase angle of iron is 40-80°, while that of stainless steel is 140-180°. The larger the amplitude of the eddy currents generated in stainless steel, the larger the size of the stainless steel. The metal detector is installed, for example, on a conveyor that transports the mixed glass raw materials to the melting furnace 11. Preferably, the metal detector has a mechanism to remove only stainless steel above a certain size from the glass raw materials. An example of such a mechanism is shown. When metal or non-metal passes through the metal detector, two analog signals, X and Y, are input from the metal detector to a PLC (Programmable Logic Controller), and the phase angle and maximum voltage are calculated. When the phase angle is between 140 and 180°, indicating stainless steel, and the maximum voltage is above a preset value, a damper installed on the conveyor opens, removing glass raw materials containing stainless steel of a certain size or larger from the conveyor and preventing the stainless steel from being fed into the melting furnace 11.

[0113] This application is based on Japanese Patent Application No. 2021-141551 filed on August 31, 2021, and its contents are incorporated herein by reference. [Explanation of Symbols]

[0114] 1. Glass manufacturing equipment 10 Melting part 11 Melting kiln 12 twill 13 Lip 20 Molding section 21 Molten metal bath 21U upstream end 22 Molten metal 23, 23A, 23B Top Roll 24 Heater 24A Central Heater 24B End Heater 25 Upstream wall 26 Downstream Wall 27 Side wall 27A Shoulder 27B First wall 27C Second wall 30 Annealing section 31 Cooling room 32 Conveyor Rolls 100 Convex glass (flat glass) 200 wedge-shaped glass 300 Windshield 301,302 Wedge-shaped glass 303 Interlayer 400 Windshield 401 Wedge-shaped glass 402 Glass 403 Interlayer 500 Wedge-shaped glass 507 Convex 503 line segment 504 Intersection (First point) 505 intersection 506 Second point

Claims

1. A method for manufacturing a glass plate, comprising floating a glass ribbon on the surface of a molten metal bath and advancing it, and bringing a plurality of top rolls into contact with both ends of the glass ribbon in the width direction to form the glass ribbon into a plate shape, The molten metal bath comprises an upstream wall, a downstream wall, and two side walls. Each of the two side walls includes a shoulder that reduces the width of the molten metal bath in the direction of the glass ribbon's movement. The ratio W / N of the distance W between the two side walls upstream of the shoulder of the molten metal bath and the distance N between the two side walls downstream of the shoulder of the molten metal bath is greater than 1.0 and less than or equal to 1.

6. A method for manufacturing a glass plate, comprising heating the ends of the glass ribbon more strongly in the width direction than the center in the width direction in the upstream region of the molten metal bath, thereby producing a glass plate where the center in the width direction is thicker than the ends.

2. A method for manufacturing a glass plate according to claim 1, wherein the glass ribbon is heated such that, at a position 20% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the viscosity of the central part of the glass ribbon in the width direction on the molten metal surface is 10^(4.5) (dPa·sec) or more.

3. A method for manufacturing a glass plate according to claim 1, wherein the glass ribbon is heated such that, at a position 20% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the viscosity of the central part of the glass ribbon in the width direction on the molten metal surface is 10^(6.0) (dPa·sec) or less.

4. A method for manufacturing a glass plate according to claim 1, wherein, at a position 32% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the difference between the temperature of the center of the glass ribbon in the width direction on the molten metal surface and the temperature of both ends of the molten metal in the width direction is 62°C or less.

5. A method for manufacturing a glass plate according to claim 1, wherein the glass ribbon is heated such that, at a position 32% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the viscosity of the central part of the glass ribbon in the width direction on the molten metal surface is 10^(4.7) (dPa·sec) or more.

6. A method for manufacturing a glass plate according to claim 1, wherein the glass ribbon is heated such that, at a position 32% from the upstream wall with respect to the length from the upstream wall to the downstream wall, the viscosity of the central part of the glass ribbon in the width direction on the molten metal surface is 10^(6.3) (dPa·sec) or less.

7. The method for manufacturing a glass plate according to claim 1, wherein the ratio of the maximum width in the width direction of the glass ribbon in the molten metal bath to the length in the width direction of the glass ribbon at the downstream end of the molten metal bath is 1.4 to 2.

2.

8. A method for manufacturing a glass plate according to claim 1, wherein the ratio a / b of the width a of the glass ribbon at a position 35% from the upstream wall to the length b of the glass ribbon in the width direction at the downstream end of the molten metal bath is 1.0 to 1.9, with respect to the length from the upstream wall to the downstream wall.

9. A method for manufacturing a plate glass according to claim 1, wherein, with respect to the length from the upstream wall to the downstream wall, at a position 20% from the upstream wall, the ratio A / B of the widthwise length A of the glass ribbon to the widthwise length B of the molten metal surface not covered by the glass ribbon is 4 to 11.

10. A method for producing wedge-shaped glass, comprising cutting a plate glass obtained by the method for producing plate glass described in any one of claims 1 to 9.

11. The aforementioned wedge-shaped glass has at least one main surface that is convex, A method for manufacturing a wedge-shaped glass according to claim 10, wherein, on a line segment passing through the centroid G of the convex surface and connecting two opposing sides of the four sides of the convex surface by the shortest distance, the point at which the wedge-shaped glass has a smaller vertical thickness when the wedge-shaped glass is placed on a horizontal surface is designated as the first point, and the point on the convex surface located at a distance of 2 / 5 of the length of the line segment from the first point is designated as the second point, and the angle between the line connecting the first point and the second point and the horizontal plane is 0.020° to 0.050°.

12. The method for manufacturing wedge-shaped glass according to claim 10, wherein the ratio T / M of the maximum and minimum thicknesses T of the wedge-shaped glass is 1.10 to 1.

40.

13. A wedge-shaped glass is obtained by cutting a plate glass obtained by the plate glass manufacturing method described in any one of claims 1 to 9. The aforementioned wedge-shaped glass and other plate glass are laminated and pressed together with an interlayer in between. A method for manufacturing laminated glass.

14. The other glass plate is the wedge-shaped glass. The method for manufacturing laminated glass according to claim 13.

15. The other glass plate is a glass plate of constant thickness. The method for manufacturing laminated glass according to claim 14.

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