Plate glass manufacturing method, plate glass manufacturing apparatus, and plate glass

Abstract

To provide a method for producing a plate glass, an apparatus for producing a plate glass, and a plate glass which achieve improved quality of snapping.SOLUTION: A method for producing a plate glass comprises a snapping step for snapping a plate glass G in a vertical posture along a scribe line S, where: the plate glass G has a first region G1 and a second region G2, which are arranged to be adjacent to each other in the width direction; the scribe line S is formed in the boundary part of the first region G1 and the second region G2 on the front surface G1a, G2a side of the plate glass G; and in the snapping step, a force directed toward the back surface G2b side is acted on the second region G2 in a state where the first region G1 is in contact with and supported by a back surface supporting member 3 from the back surface G1b side of the plate glass and the second region G2 is sucked and held by a suction mechanism 6 from the back surface G2b side, thereby cutting out the second region G2, while causing a crack to extend, starting from an end of the scribe line S.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an improvement in a method for manufacturing a glass sheet, an apparatus for manufacturing a glass sheet, and a glass sheet. [Background technology]

[0002] As is well known, glass sheets are used as substrates or covers in displays (e.g., liquid crystal displays, plasma displays, organic electroluminescence (EL) displays, etc.) and organic electroluminescence (EL) lighting. Manufacturing this type of glass sheet involves processes such as sequentially cutting glass sheets of predetermined lengths from a glass ribbon and removing unnecessary areas along the edges of the glass sheet. In these processes, scribe lines are formed in the glass ribbon or glass sheet, and then the glass ribbon or glass sheet is bent and broken along the scribe lines.

[0003] A specific example of a method for obtaining a glass sheet by bending and splitting is the method disclosed in Patent Document 1. In the method disclosed in this document, a scribe line is formed on the front surface of the glass sheet at the boundary between a first region and a second region that are arranged adjacent to each other in the width direction of the glass sheet. Then, while the first region is supported in contact with the back surface by a back surface support member, the second region is pressed toward the back surface by a rolling element. This applies a bending stress to the glass sheet, causing it to bend and split along the scribe line, and the second region is cut out. The bending and splitting is performed while the glass sheet is supported in a vertical position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-226549 Summary of the Invention [Problem to be solved by the invention]

[0005] When bending stress is applied to a glass sheet using the method described in Patent Document 1, non-uniform bending stress acts on the scribe line. Warping inevitably occurs in the glass sheet in its longitudinal cross-section, and the shape and size of this warping varies from glass sheet to glass sheet. This warping is particularly pronounced when the glass sheet has a thickness of 500 μm or less. When such a glass sheet is broken using the method described in Patent Document 1, the position of the origin of the crack that propagates during the breaking process may change due to the change in the shape of the warp in the glass sheet, and the crack may propagate from the middle of the scribe line. In this case, there are problems such as misalignment of the breaking position, breakage of the glass sheet, chipping (unwanted chipping on the broken edge), and excessive generation of glass powder, resulting in a decrease in the quality of the breaking process.

[0006] An object of the present invention is to improve the quality of breaking a glass sheet. [Means for solving the problem]

[0007] The present invention, which has been invented to solve the above-mentioned problems, provides a method for manufacturing a glass sheet, including a bending step of bending a vertically oriented glass sheet along a scribe line, wherein a first region and a second region are arranged adjacent to each other in the width direction of the glass sheet, the scribe line being formed at a boundary between the first region and the second region and on the front side of the glass sheet, and the bending step includes supporting the first region in contact with the back side of the glass sheet with a back support member while suction-holding the second region from the back side with a suction mechanism, and applying a force to the second region toward the back side to cut out the second region and propagating a crack starting from the end of the scribe line. By propagating a crack starting from the end of the scribe line, it is possible to suppress breakage and chipping of the glass sheet, the excessive generation of glass powder, and the like, and to improve the quality of the bending.

[0008] In the above configuration, it is preferable that the suction mechanism includes a plurality of suction members arranged along the scribe line, and in the breaking step, the second region is held by suction from the back surface side by the suction members, thereby causing the height position of the second region that serves as the starting point to protrude toward the front surface. In the breaking step according to the present invention, a large bending stress acts on the end of the scribe line that protrudes toward the front surface side of the glass sheet, so that the crack reliably propagates from the end of the scribe line as the starting point, thereby reliably improving the quality of the breaking.

[0009] In the above configuration, it is preferable that the upper end of the glass plate is held by a gripping mechanism, the scribe line extends in the vertical direction, and suction is started sequentially from the uppermost suction member among the plurality of suction members. If a warped glass plate is simultaneously suctioned by multiple suction members, the glass plate is suctioned and held in a warped state, and the longitudinal cross-sectional shape of the suctioned and held glass plate is likely to vary. On the other hand, if suction is started sequentially from the uppermost suction member, the warp is corrected during the suction process, and the cross-sectional shape of the suctioned and held glass plate is stabilized. This more reliably improves the quality of the bend cutting.

[0010] In the above configuration, it is preferable that the suction pressure of the suction member at the end protruding toward the front surface among the plurality of suction members is lower than that of the other suction members. Here, the suction pressure is atmospheric pressure minus the pressure inside the suction member. Because the suction member (e.g., a suction pad) is flexible, it deforms so as to draw the glass plate toward the suction member when suctioning the glass plate. A suction member with a low suction pressure draws the glass plate toward the suction member less than a suction member with a high suction pressure, causing the glass plate to protrude toward the front surface. Therefore, by lowering the suction pressure of the suction member located above or below, the end of the scribe line can be caused to protrude toward the front surface.

[0011] In the above configuration, in the breaking step, it is preferable that the first region and the back surface support member are brought into contact with each other, thereby causing the height position of the first region, which serves as the starting point, to protrude toward the front surface. With this configuration, by extending a crack starting from the end of the scribe line, it is possible to suppress breakage and chipping of the glass sheet, the generation of excessive glass powder, and the like, and to improve the quality of breaking.

[0012] The present invention also provides a glass sheet manufacturing apparatus including a breaking device that breaks a vertically oriented glass sheet along a scribe line, wherein a first region and a second region are arranged adjacent to each other in the width direction of the glass sheet, the scribe line is formed at the boundary between the first region and the second region and on the front side of the glass sheet, and the breaking device includes a back surface support member that contacts and supports the first region from the back surface of the glass sheet, a suction mechanism that suction-holds the second region from the back surface, and a pressing member that applies a force to the second region toward the back surface, and is configured to extend a crack starting from an end of the scribe line. This configuration can achieve the same effects as the previously described manufacturing method that has substantially the same configuration as the manufacturing apparatus.

[0013] The plate glass according to the present invention is a rectangular plate glass having two first end faces extending in the drawing direction and two second end faces extending in a width direction intersecting the drawing direction, wherein at least one of the first end faces is a cut surface formed by bending and has scribe lines, and the starting point of the bending and bending is located at an end of the scribe lines.

[0014] The cut surface formed by the bend has rib marks spaced closer together the closer to the start of the bend. Rib marks are arc-shaped wave patterns formed perpendicular to the direction of crack propagation. When tensile stress acts on an area with many rib marks, cracks can propagate from the rib marks, causing the glass sheet to break.

[0015] When manufacturing substrates and covers for displays and organic EL lighting using glass sheets, the glass sheets are sometimes transported in a vertical position. Specifically, the chuck mechanism of the transport device clamps the top of the vertically oriented glass sheets, and the glass sheets are transported in a suspended state. When transported in this manner, the glass sheets are prone to swing like a pendulum due to the effects of air resistance and inertial forces. If the swinging becomes too severe, tensile stress acts on the curved portions, potentially causing breakage of the glass sheets.

[0016] In a glass sheet transported in a vertical position, the region at the same height as the upper end of the scribe line marks is clamped by a chuck mechanism, so the glass sheet is less likely to bend even if it shakes. In addition, in a glass sheet transported in a vertical position, the region at the same height as the lower end of the scribe line marks is not clamped and is free, so the glass sheet is less likely to bend even if it shakes. Therefore, since the starting point of the cleavage is at the end of the scribe line marks, the region including the starting point of the cleavage is less likely to bend and is less likely to be subjected to tensile stress. Therefore, a glass sheet having this configuration is less likely to break when transported in a vertical position. [Effects of the Invention]

[0017] According to the present invention, the quality of the cleavage can be improved by extending the crack starting from the end of the scribe line. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing a breaking device included in a sheet glass manufacturing apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 3] FIG. 3 is a perspective view showing the operation of the bend-breaking device included in the apparatus for manufacturing a glass sheet according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view taken along CC in FIG. [Figure 5] 5(a), (b), and (c) are top views showing a procedure for breaking a glass sheet using a breaking device included in the glass sheet manufacturing apparatus according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a top view showing a breaking device included in the sheet glass manufacturing apparatus according to the first embodiment of the present invention. [Figure 7] FIG. 7 is a perspective view showing the operation of a breaking device included in the apparatus for manufacturing a glass sheet according to the second embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view taken along line DD in FIG. [Figure 9] 9(a), (b), and (c) are top views showing a procedure for breaking a glass sheet using a breaking device included in a glass sheet manufacturing apparatus according to a second embodiment of the present invention. [Figure 10] FIG. 10 is a perspective view showing the operation of a breaking device included in a sheet glass manufacturing apparatus according to a third embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view taken along the line E-E in FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along the line E-E of FIG. 10, showing only the glass sheet. [Figure 13] 13(a), (b), and (c) are top views showing a procedure for breaking a glass sheet using a breaking device included in a glass sheet manufacturing apparatus according to a third embodiment of the present invention. [Figure 14] FIG. 14 is a perspective view showing the operation of a breaking device included in a sheet glass manufacturing apparatus according to a fourth embodiment of the present invention. [Figure 15] FIG. 15 is a cross-sectional view taken along the line FF in FIG. [Figure 16] FIG. 16 is a cross-sectional view taken along the line FF in FIG. 14, showing only the glass plate. [Figure 17] 17(a), (b), and (c) are top views showing a procedure for breaking a glass sheet using a breaking device included in a glass sheet manufacturing apparatus according to a fourth embodiment of the present invention. [Figure 18] FIG. 18 is a perspective view showing a glass plate according to one embodiment of the present invention. [Figure 19] FIG. 19 is a perspective view showing an end face of a glass sheet according to one embodiment of the present invention. [Figure 20]FIG. 20 is a perspective view showing an end face of a glass sheet according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of a method for manufacturing a glass sheet, an apparatus for manufacturing a glass sheet, and a glass sheet according to the present invention will be described with reference to the accompanying drawings.

[0020] (First embodiment) FIG. 1 shows a breaking device 1 and a glass sheet G included in a glass sheet manufacturing apparatus according to this embodiment. The glass sheet G has a first region G1 and a second region G2 arranged adjacent to each other in the width direction. The first region G1 is the region that will become the finished product of the glass sheet G, and has a uniform thickness throughout. The second region G2 is the region that will be cut out from the glass sheet G and discarded, and has an edge Ge at the leading end in the width direction (the leading end on the left in the illustrated example) that is thicker than the first region G1. At the boundary between the first region G1 and the second region G2, a scribe line S is formed on the surfaces G1a and G2a. In the illustrated example, the scribe line S does not reach the upper and lower end surfaces of the glass sheet G. Note that the scribe line S may reach the upper and lower end surfaces of the glass sheet G. In the following description, for convenience, the first region G1 will be referred to as the effective region, and the second region G2 will be referred to as the unnecessary region.

[0021] The glass sheet G is suspended and supported in a vertical position so that the scribe line S faces the up-down direction. The thickness of the glass sheet G (sheet thickness of the region excluding the edge portions Ge) is, for example, 50 to 2000 μm. Since the glass sheet G is highly flexible and warpage in the vertical cross section becomes significant, thereby enhancing the effects of the present invention, the thickness of the glass sheet G is preferably 50 to 500 μm, and more preferably 50 to 400 μm. The specific shape of the warpage is a shape in which the scribe line S on the surfaces G1a, G2a of the glass sheet G and any imaginary line parallel to the scribe line S are curved. Furthermore, the shape of this warpage is not uniform and changes depending on the manufacturing equipment, manufacturing conditions, and the passage of time.

[0022] The glass sheet G can be obtained, for example, by the following procedure. (1) A glass ribbon is formed by the overflow downdraw method. (2) The formed glass ribbon is slowly cooled. (3) The annealed glass ribbon is folded and cut in the width direction to cut out glass sheets G from the glass ribbon.

[0023] When a glass sheet G is obtained from the glass ribbon formed by the overflow downdraw method as described above, the front surfaces G1a, G2a and the back surfaces G1b, G2b are all fire-polished surfaces, resulting in excellent surface quality. In this case, although not shown in the drawings, striped patterns extending in the vertical direction (sheet drawing direction) are formed on the front surfaces G1a, G2a and the back surfaces G1b, G2b of the glass sheet G. In addition, the upper and lower end surfaces of the glass sheet G are both cut surfaces formed by bending.

[0024] The size of the glass sheet G after bending is, for example, 1800 mm×2000 mm or more, preferably 2200 mm×2500 mm or more, more preferably 2600 mm×3000 mm or more, and even more preferably 2900 mm×3300 mm or more.

[0025] Examples of the composition of the plate glass G include alkali-free glass, borosilicate glass, soda glass (soda-lime glass), high-silica glass, and other oxide-based glasses containing silicon oxide as a main component. The plate glass G may be chemically strengthened glass, in which case aluminosilicate glass can be used.

[0026] The breaking device 1 breaks the glass sheet G along the scribe line S to remove the unnecessary region G2. In detail, the breaking device 1 includes a gripping mechanism 2 that grips the upper end of the effective region G1, a back surface support member 3 arranged on the back surface G1b side of the effective region G1, a pressing member 4 arranged opposite the back surface support member 3 on the front surface G1a side of the effective region G1, a suction mechanism 6 arranged on the back surface G2b side of the unnecessary region G2, and a pushing member 5 arranged opposite the suction mechanism 6 on the front surface G2a side of the unnecessary region G2.

[0027] The gripping mechanism 2 has a pair of gripping pieces 21 and a drive unit 22 that moves the pair of gripping pieces 21 toward and away from each other. The configuration of the drive unit 22 is not limited to that shown in the example. The pair of gripping pieces 21 grip the upper end of the effective area G1 when they approach each other to become a closed state, and release the grip of the upper end of the effective area G1 when they move away from each other to become an open state.

[0028] The gripping mechanism 2 is slidably held on a rail (not shown) extending along the width direction above the glass sheet G, and serves to transport the glass sheet G in and out of the bending / breaking position. When bending / breaking the glass sheet G at the bending / breaking position, the gripping mechanism 2 stops while gripping the upper end of the effective area G1. In this case, the lower end of the glass sheet G is not held and is in a free state. The gripping mechanism 2 grips the upper end of the effective area G1 at multiple locations in the width direction (two locations in this embodiment (one location is not shown)).

[0029] The back surface support member 3 contacts and supports the effective area G1 from the back surface G1b side when the glass sheet G is broken. The back surface support member 3 moves toward and away from the back surface G1b of the effective area G1 by the operation of a driving means (not shown) such as a fluid pressure cylinder such as an air cylinder, a ball screw mechanism, or a robot arm. The back surface support member 3 is a columnar or plate-like body that is long in the vertical direction. The back surface support member 3 is arranged along the scribe line S, and the widthwise separation distance between the back surface support member 3 and the scribe line S (the separation distance when the back surface support member 3 contacts the effective area G1) is preferably 10 to 30 mm, and more preferably 10 to 20 mm. In the illustrated example, the back surface support member 3 extends from the upper and lower end surfaces of the effective area G1, but it does not have to extend from the upper and lower end surfaces of the effective area G1.

[0030] The pressing member 4 presses the effective area G1 against the rear surface support member 3 when the glass sheet G is broken. The pressing member 4 moves toward and away from the surface G1a of the effective area G1 by the operation of a driving means (not shown) such as a fluid pressure cylinder such as an air cylinder, a ball screw mechanism, or a robot arm. In this embodiment, the pressing member 4 is a columnar or plate-like body that is long in the vertical direction. In the illustrated example, the pressing member 4 extends from the upper and lower end surfaces of the effective area G1, but it does not have to extend from the upper and lower end surfaces of the effective area G1.

[0031] 2 is a cross-sectional view taken along the line B-B in FIG. 1. The suction mechanism 6 includes a holding base 61 that is long in the vertical direction and a plurality of suction members 62 attached to the holding base 61. The holding base 61 moves while rotating (for example, moves while rotating in the direction of arrow A in FIG. 1) due to the operation of a driving means (not shown) such as a robot arm. The suction members 62 are, for example, suction pads that suction-hold the back surface G2b of the unnecessary region G2 by negative pressure, and are made of an elastic material such as rubber or resin. The suction members 62 are attached to the holding base 61 in a vertical line. In this embodiment, three suction members 62 are attached, but this is not limiting. Two or four or more suction members 62 may also be used.

[0032] The pressing member 5 has a flat portion 51 that contacts the surface G2a of the unneeded region G2, and in this embodiment, is a plate-like member that is elongated in the vertical direction. The pressing member 5 moves while rotating (for example, moves while rotating in the direction of arrow A shown in FIG. 1) due to the operation of a driving means (not shown) such as a robot arm, thereby applying a pressing force to the unneeded region G2 toward the back surface G2b. In the illustrated example, the pressing member 5 extends from the upper and lower end surfaces of the unneeded region G2, but it does not have to extend from the upper and lower end surfaces of the unneeded region G2.

[0033] Next, a method for manufacturing a glass sheet using the manufacturing apparatus according to the first embodiment will be described.

[0034] First, in a process upstream of the position shown in FIG. 1 , a glass sheet G is suspended and supported by a gripping mechanism 2, and a scribe line S is formed on the front surfaces G1a and G2a of the glass sheet G by pressing with a wheel cutter, irradiating with a laser, or the like. Specifically, a scribe line S is formed at the boundary between the effective region G1 and the unnecessary region G2 of the glass sheet G. Next, the glass sheet G with the scribe line S formed thereon is transported widthwise while suspended and supported by the gripping mechanism 2, until the glass sheet G reaches the breaking position shown in FIG. 1 . At this point, the pressing member 4 and the back surface support member 3 are spaced apart from the front surface G1a and the back surface G1b of the effective region G1, respectively, and the pushing member 5 and suction mechanism 6 are also spaced apart from the front surface G2a and the back surface G2b of the unnecessary region G2, respectively. In this state, warping occurs in the glass sheet G in its longitudinal cross section.

[0035] Thereafter, the back surface support member 3 moves toward the effective area G1, and the pressing member 4 also moves toward the effective area G1. As shown in Fig. 3, when the movement of the back surface support member 3 and the pressing member 4 is completed, the effective area G1 is supported by the back surface support member 3 in a state where it is sandwiched between the back surface support member 3 and the pressing member 4. In addition, the suction mechanism 6 moves toward the unnecessary area G2, and the suction member 62 comes into contact with the back surface G2b of the unnecessary area G2.

[0036] As shown in FIG. 4 , when the chucking member 62 contacts the unnecessary region G2, the topmost chucking member 621 begins chucking. After a predetermined time has elapsed, the second-highest chucking member 622 begins chucking. After another predetermined time has elapsed, the third-highest chucking member 623 begins chucking. Here, if a warped glass sheet G is simultaneously chucking using multiple chucking members 621-623, the chucking result will be warped in the vertical cross-sectional shape of the chucking-held glass sheet G, and the vertical cross-sectional shape of the chucking-held glass sheet G will likely vary. On the other hand, if the chucking members 621-623 chucking in order from top to bottom as described above, the warp is corrected during the chucking process, and the cross-sectional shape of the chucking-held glass sheet G will be stable. In this embodiment, three chucking members 62 are used. However, even if two or four or more chucking members 62 are used, the same effect can be obtained by chucking the glass sheet G in order from the top.

[0037] The suction pressure applied by the suction member 62 to suction the glass sheet G is set lower as the suction member 62 is positioned higher in the vertical direction of the glass sheet G. Here, the suction pressure is atmospheric pressure minus the pressure inside the suction member 62. As a result, in the unnecessary region G2, a region at the same height as the upper end of the scribe line S (hereinafter also referred to as the "upper end region G2U of the unnecessary region G2") protrudes further toward the front surface G2a than a region at the same height as the middle or lower end of the scribe line S. The protrusion amount D2U of the upper end region G2U of the unnecessary region G2 is, for example, 10 to 300 mm, and preferably 30 to 100 mm. This ensures that the upper end of the scribe line S serves as the starting point for breaking, and also reliably prevents damage to the glass sheet G during breaking.

[0038] 5(a), (b), and (c) are top views of the glass sheet breaking apparatus showing the subsequent steps of breaking the glass sheet G. FIG. 5(a) shows the initial stage of the breaking process, in which the unnecessary region G2 has a shape in which the upper end region G2U protrudes toward the front surface G2a. From this state, the pressing member 5 is moved, and the pressing member 5 comes into contact with the unnecessary region G2 as shown in FIG. 5(a). As the pressing member 5 continues to move, the unnecessary region G2 is bent toward the back surface G2b, with the back surface support member 3 as a fulcrum, as shown in FIG. 5(b). As the pressing member 5 moves, it rotates. In response, the suction mechanism 6 rotates while moving in the direction of arrow A. The suction mechanism 6 does not substantially apply a pulling force toward the back surface G2b to the unnecessary region G2. During this process, a bending deformation occurs in the width direction around the scribe line S, which causes a bending stress to act on the scribe line S. Furthermore, because the upper end region G2U of the unnecessary region G2 protrudes toward the front surface G2a, the largest bending stress acts on the upper end of the scribe line S. Thereafter, as the pressing member 5 further moves, when the bending stress acting on the upper end of the scribe line S becomes sufficiently large, a crack extends from the upper end of the scribe line S in the thickness direction and in the direction of the scribe line S. As the crack extends along the entire scribe line S in this manner, the glass sheet G is broken along the scribe line S, as shown in FIG. 5(c). After the glass sheet G is broken and the unnecessary region G2 is cut out, the unnecessary region G2 is transported to a retracted position while being held by the suction mechanism 6, and then is released from the holding by the suction mechanism 6 and dropped for collection.

[0039] The above-described glass cutting device 1 and cutting process have been described with reference to the unnecessary region G2 at one widthwise end of the glass sheet G. However, the unnecessary region G2 is typically formed at both widthwise ends of the glass sheet G. To perform cutting of the glass sheet G to remove the unnecessary region G2, the following configuration is adopted. That is, as shown in FIG. 6 , the glass sheet G has an effective region G1 at the center of the widthwise direction and unnecessary regions G2 on both sides of the effective region G1. Scribe lines S are formed at the two boundaries between the effective region G1 and each unnecessary region G2. The glass sheet G is cut along these two scribe lines S by a glass cutting device 1 disposed corresponding to each unnecessary region G2. Each of these glass cutting devices 1 has a pressing member 4 and a back surface support member 3 disposed on the front surface G1a and back surface G1b of the effective region G1, respectively, and a pushing member 5 and a suction mechanism 6 disposed on the front surface G2a and back surface G2b of the unnecessary region G2, respectively. The pushing member 5 and the suction mechanism 6 are configured to rotate and move in the direction of arrow A. The detailed configuration of the two cutting devices 1 is the same as that of the above-described cutting device 1. In this case, the two cutting devices 1 may perform cutting simultaneously, or one cutting device 1 may complete cutting before the other cutting device 1 performs cutting. Alternatively, one cutting device 1 and the other cutting device 1 may be arranged at a distance longer than the width of the glass sheet G, and after one unnecessary region G2 is broken and removed by one cutting device 1, the glass sheet G may be moved in the width direction, and then the other unnecessary region G2 may be broken and removed by the other cutting device 1. Furthermore, separately from this, one bending / cutting device 1 may be used, and one unnecessary area G2 may be bent / cut and removed by the bending / cutting device 1, and then the glass plate G may be rotated 180 degrees in a planar view, and then the other unnecessary area G2 may be bent / cut and removed by the bending / cutting device 1.

[0040] Second Embodiment Hereinafter, a method for manufacturing a glass sheet according to a second embodiment of the present invention will be described. In the description of the second embodiment, components that are substantially the same as those described in the first embodiment will be denoted by the same reference numerals, and redundant description will be omitted. Only components that differ from the first embodiment will be described.

[0041] The manufacturing apparatus according to the second embodiment has the same configuration as the manufacturing apparatus according to the first embodiment, but the suction pressure with which the suction member 62 suctions the glass sheet G is set lower as the suction member 62 is positioned lower in the vertical direction of the glass sheet G. As a result, in the second embodiment, a crack is propagated starting from the lower end of the scribe line S.

[0042] 7 and 8, in the unnecessary region G2, a region whose height is the same as the bottom end of the scribe line S (hereinafter also referred to as the "bottom end region G2L of the unnecessary region G2") protrudes toward the surface G2a more than a region whose height is the same as the middle or top end of the scribe line S. The protrusion amount D2L of the bottom end region G2L of the effective region G2 is preferably 10 to 300 mm, and more preferably 10 to 100 mm.

[0043] 9(a), 9(b), and 9(c) are top views of the breaking device showing the subsequent procedure for breaking the glass sheet G. FIG. 9(a) shows the initial stage of the breaking process, in which the unnecessary region G2 has a shape in which the lower end region G2L protrudes toward the front surface G2a. From this state, by moving the pressing member 5, the unnecessary region G2 is bent toward the back surface G2b, with the back surface support member 3 as a fulcrum, as shown in FIG. 9(b). During this process, a bending deformation occurs in the width direction around the scribe line S, which causes bending stress to act on the scribe line S. Furthermore, because the lower end region G2L of the unnecessary region G2 protrudes toward the front surface G2a, the largest bending stress acts on the lower end of the scribe line S. After this, as the pressing member 5 continues to move, when the bending stress acting on the lower end of the scribe line S becomes sufficiently large, a crack propagates from the lower end of the scribe line S in the thickness direction and in the direction of the scribe line S. In this way, the crack propagates along the entire scribe line S, and the glass sheet G is broken along the scribe line S as shown in FIG. 9(c).

[0044] (Third embodiment) Hereinafter, a method and an apparatus for manufacturing a glass sheet according to a third embodiment of the present invention will be described. In the description of the third embodiment, components that are substantially the same as those described in the first and second embodiments are designated by the same reference numerals, and redundant description will be omitted. Only components that differ from the first and second embodiments will be described.

[0045] 10 shows a sheet glass cutting device 1 included in a sheet glass manufacturing apparatus according to a third embodiment. The sheet glass cutting device 1 according to the third embodiment differs from the sheet glass cutting device 1 according to the first embodiment in the configurations of the back surface support member 3 and the pressing member 4, and in the setting of the suction pressure of the suction member 62.

[0046] FIG. 11 is a cross-sectional view taken along line E-E in FIG. 10. The pressing member 4 has a lower convex portion 43 at the lower end of an opposing portion 42 that faces the surface G1a of the glass sheet G (effective area G1). More specifically, the pressing member 4 has a columnar or plate-shaped supporting substrate 41. The lower convex portion 43, whose surface is curved, is fixed to the surface of the supporting substrate 41. The surface of the lower convex portion 43 is smoothly curved so that the length that it protrudes from the supporting substrate 41 gradually decreases from the bottom to the top. The surface of the lower convex portion 43 may be an inclined surface.

[0047] The lower convex portion 43 is disposed at a position that does not overlap in the vertical direction with the gripping piece 21 that grips the upper end of the effective region G1. That is, the upper end 43U of the lower convex portion 43 is located below the lower end 21L of the gripping piece 21. The lower convex portion 43 is softer than the glass sheet G and the supporting substrate 41 and has excellent elasticity or cushioning properties, and is formed, for example, from plastic corrugated cardboard, porous resin or foamed resin typified by Paronia (registered trademark), FC Nylon (registered trademark), or the like. A covering sheet 44 is attached to the surfaces of the supporting substrate 41 and the lower convex portion 43 to cover them. The covering sheet 44 is softer than the lower convex portion 43 and is formed, for example, from porous resin or foamed resin typified by sponge or low-resilience sponge, or the like.

[0048] The rear surface support member 3 has an upper convex portion 33 at the upper end of an opposing portion 32 that faces the rear surface G1b of the glass plate G (effective area G1). More specifically, the rear surface support member 3 has a columnar or plate-shaped support base 31. The upper convex portion 33 is fixed to the surface portion of the support base 31. The surface of the upper convex portion 33 is smoothly curved so that the length of the portion protruding from the support base 31 gradually decreases from the top to the bottom. The surface portion of the support base 31 may be a curved surface.

[0049] The upper protrusion 33 is disposed at a position overlapping in the vertical direction with the gripping piece 21 gripping the upper end of the effective region G1. That is, the upper end 33U of the upper protrusion 33 is located above the upper end 21U of the gripping piece 21, and the lower end 33L of the upper protrusion 33 is located below the lower end 21L of the gripping piece 21. The upper protrusion 33 may be disposed at a position overlapping only a portion of the gripping piece 21 in the vertical direction. In this embodiment, the upper end 33U of the upper protrusion 33 protrudes from the upper end of the glass sheet G, but it does not have to protrude. The upper protrusion 33 is softer than the glass sheet G and the supporting substrate 31 and has excellent elasticity or cushioning properties, and is formed of, for example, plastic corrugated cardboard, a porous resin or foam resin typified by Paronia (registered trademark), FC Nylon (registered trademark), or the like. A covering sheet 34 is attached to the surfaces of the support base 31 and the upper convex portion 33. The covering sheet 34 is softer than the upper convex portion 33 and is made of, for example, a porous resin or foamed resin, such as a sponge or a low-resilience sponge.

[0050] Next, a method for manufacturing a glass sheet using the manufacturing apparatus according to the third embodiment will be described.

[0051] As in the first embodiment, after the glass sheet G on which the scribe line S is formed reaches the breaking position, the back surface support member 3 moves toward the effective region G1, and the pressing member 4 also moves toward the effective region G1. As shown in FIG. 11 , when the movement of the back surface support member 3 and the pressing member 4 is completed, the effective region G1 is sandwiched between the back surface support member 3 and the pressing member 4 and supported by the back surface support member 3. As a result, as shown in FIG. 12 , a region of the effective region G1 that is at the same height as the upper end of the scribe line S (hereinafter also referred to as the "upper end region G1U of the effective region G1") protrudes toward the front surface G1a more than regions that are at the same height as the middle or lower end of the scribe line S. The protrusion amount D1U of the upper end region G1U of the effective region G1 is preferably 10 to 300 mm, more preferably 10 to 100 mm. Furthermore, the suction mechanism 6 moves toward the unnecessary region G2, and the suction member 62 contacts the back surface G2b of the unnecessary region G2.

[0052] 10, when the suction members 62 come into contact with the unnecessary region G2, they suction the unnecessary region G2 in order, starting with the suction member 62 located at the top, as in the first embodiment. The suction pressures of the multiple suction members 62 are set equal. Therefore, the upper end region G2U of the unnecessary region G2 does not protrude, and the surface G2a of the unnecessary region G2 is approximately parallel to the vertical plane.

[0053] 13(a), (b), and (c) are top views of the breaking device showing the subsequent procedure for breaking the glass sheet G. FIG. 13(a) shows the initial stage of the breaking process, in which the effective region G1 has a shape in which the upper end region G1U protrudes toward the front surface G1a. From this state, by moving the pressing member 5, the unnecessary region G2 is bent toward the back surface G2b, with the back surface support member 3 as a fulcrum, as shown in FIG. 13(b). During this process, a bending deformation occurs in the width direction around the scribe line S, which causes bending stress to act on the scribe line S. Furthermore, because the upper end region G1U of the effective region G1 protrudes toward the front surface G1a, the largest bending stress acts on the upper end of the scribe line S. After this, as the pressing member 5 continues to move, when the bending stress acting on the upper end of the scribe line S becomes sufficiently large, a crack propagates from the upper end of the scribe line S in the thickness direction and in the direction of the scribe line S. In this way, the crack propagates along the entire scribe line S, and the glass sheet G is broken along the scribe line S, as shown in FIG. 13(c).

[0054] (Fourth embodiment) Hereinafter, a method and an apparatus for manufacturing a glass sheet according to a fourth embodiment of the present invention will be described. In the description of the fourth embodiment, components that are substantially the same as those described in the first, second, and third embodiments are designated by the same reference numerals, and redundant description will be omitted. Only components that differ from the first, second, and third embodiments will be described.

[0055] 14 shows a sheet glass cutting device 1 included in a sheet glass manufacturing apparatus according to a fourth embodiment. The sheet glass cutting device 1 according to the fourth embodiment differs from the sheet glass cutting device 1 according to the third embodiment in the configurations of a back surface support member 3 and a pressing member 4.

[0056] Fig. 15 is a cross-sectional view taken along line F-F in Fig. 14. The rear surface support member 3 has a lower protrusion 35 at the lower end of an opposing portion 32 that faces the rear surface G1b of the glass plate G (effective area G1). More specifically, the rear surface support member 3 has a columnar or plate-shaped support base 31. The lower protrusion 35, whose surface is curved, is fixed to the surface of the support base 31. The lower protrusion 35 has the same material and shape as the lower protrusion 43 of the pressing member 4 in the third embodiment.

[0057] The pressing member 4 has an upper convex portion 45 at the upper end of a facing portion 42 that faces the front surface G1a of the glass sheet G (effective area G1). More specifically, the pressing member 4 has a columnar or plate-shaped supporting substrate 41. The upper convex portion 45, whose surface is curved, is fixed to the front surface of the supporting substrate 41. The upper convex portion 45 has the same material and shape as the upper convex portion 33 of the back surface supporting member 3 in the third embodiment.

[0058] Next, a method for manufacturing a glass sheet using the manufacturing apparatus according to the fourth embodiment will be described.

[0059] As in the first embodiment, after the glass sheet G on which the scribe line S is formed reaches the breaking position, the back surface support member 3 moves toward the effective region G1, and the pressing member 4 also moves toward the effective region G1. As shown in FIG. 15, when the movement of the back surface support member 3 and the pressing member 4 is completed, the effective region G1 is sandwiched between the back surface support member 3 and the pressing member 4 and supported by the back surface support member 3. As a result, as shown in FIG. 16, in the effective region G1, a region at the same height as the lower end of the scribe line S (hereinafter also referred to as the "lower end region G1L of the effective region G1") protrudes toward the front surface G1a more than regions at the same height as the middle or upper end of the scribe line S. The protrusion amount D1L of the lower end region G1L of the effective region G1 is preferably 10 to 300 mm, more preferably 10 to 100 mm. Furthermore, the suction mechanism 6 moves toward the unnecessary region G2, and the suction member 62 contacts the back surface G2b of the unnecessary region G2.

[0060] As shown in FIG. 14, when the attraction member 62 comes into contact with the unnecessary area G2, attraction is performed in the same manner as in the third embodiment.

[0061] 17(a), (b), and (c) are top views of the breaking device showing the subsequent procedure for breaking the glass sheet G. FIG. 17(a) shows the initial stage of the breaking process, in which the effective region G1 has a shape in which the lower end region G1L protrudes toward the front surface G1a. From this state, by moving the pressing member 5, the unnecessary region G2 is bent toward the back surface G2b, with the back surface support member 3 as a fulcrum, as shown in FIG. 17(b). During this process, a bending deformation occurs in the width direction around the scribe line S, which causes bending stress to act on the scribe line S. Furthermore, because the lower end region G1L of the effective region G1 protrudes toward the front surface G1a, the largest bending stress acts on the upper end of the scribe line S. After this, as the pressing member 5 continues to move, when the bending stress acting on the upper end of the scribe line S becomes sufficiently large, a crack propagates from the lower end of the scribe line S in the thickness direction and in the direction of the scribe line S. In this way, the crack propagates along the entire scribe line S, and the glass sheet G is broken along the scribe line S, as shown in FIG. 17(c).

[0062] According to the above-described glass sheet manufacturing apparatus and glass sheet manufacturing method using the same, the end of the scribe line can be protruded to the front side when breaking the glass sheet. This allows the crack to extend from the end of the scribe line as a starting point, thereby improving the quality of breaking. Furthermore, by starting suction with the suction members located at the top, warping is corrected during the suction process, and the cross-sectional shape of the suction-held glass sheet can be stabilized.

[0063] The reason why the present invention can improve the quality of bending and breaking glass sheets, more specifically, why it can suppress breakage, chipping, and excessive generation of glass powder, is unclear. The inventors conducted a test in which 100 glass sheets were bent and broken using the first embodiment, with cracks propagating from the upper end of the scribe line. As a result, no breakage, chipping, or excessive generation of glass powder was observed. The glass sheets used in the test measured 3500 mm × 3500 mm and had a thickness of 500 μm. For comparison, a test was conducted in which 100 glass sheets were bent and broken by changing the suction pressure to cause the center of the scribe line to protrude toward the front side, with cracks propagating from the center of the scribe line. As a result, four glass sheets were broken, 13 glass sheets were chipped, and 15 glass sheets were subjected to excessive glass powder.

[0064] Here, the end of the scribe line S refers to a range from the tip of the scribe line S to less than 25% of the length of the scribe line S. It is more preferable that the starting point of the crack is located on the tip side of the end of the scribe line S, in other words, it is located in a range from the tip of the scribe line S to less than 12.5% ​​of the length of the scribe line S.

[0065] Next, a glass plate according to an embodiment of the present invention will be described.

[0066] As shown in FIG. 18, the sheet glass G manufactured by the sheet glass manufacturing apparatus and manufacturing method using the same according to an embodiment of the present invention has a rectangular shape having two first end faces G4 extending along the sheet drawing direction Z and two second end faces G5 extending in a width direction intersecting the sheet drawing direction Z.

[0067] The drawing direction Z of the glass sheet G can be observed as a striped pattern by, for example, irradiating the glass sheet G with light from a light source (e.g., a xenon light) while adjusting the angle of the glass sheet G in a darkroom and projecting the transmitted light onto a screen. Therefore, the drawing direction Z during forming can be identified even in the state of the glass sheet G after forming.

[0068] At least one first end surface G4 is a cut surface formed by bending and has scribe lines S1 and rib marks RM, as shown in FIGS. 19 and 20 . The rib marks RM are arc-shaped wave patterns formed perpendicular to the crack propagation direction and indicate the direction of crack propagation. FIG. 19 shows a glass sheet G that has been bent and broken by a crack that originates at the upper end of the scribe line S1 and continues to be bent downward. FIG. 20 shows a glass sheet G that has been bent and broken by a crack that originates at the lower end of the scribe line S1 and continues to be bent upward. The closer to the origin of the crack that propagates during bending, the narrower the spacing between adjacent rib marks RM. When tensile stress acts in an area where many rib marks RM exist, cracks may propagate from the rib marks RM, causing the glass sheet G to break.

[0069] When using glass sheets G to manufacture substrates or covers for displays and organic EL lighting, the glass sheets G are sometimes transported in a vertical position. More specifically, the upper part of the glass sheets G in a vertical position is clamped by a chuck mechanism (not shown) of the transport device, and the glass sheets G are transported in a suspended state. When transported in this manner, the glass sheets G tend to swing like a pendulum due to the influence of air resistance, inertial forces, and the like. If the swinging becomes too great, tensile stress acts on the curved portions due to the swinging, which may cause the glass sheets G to break.

[0070] Of the glass sheet G transported in a vertical position, the region at the same height as the upper end of the scribe line S1 is clamped by a chuck mechanism, so the glass sheet G is less likely to bend even if it shakes. Also, of the glass sheet G transported in a vertical position, the region at the same height as the lower end of the scribe line S1 is not clamped and is in a free state, so the glass sheet G is less likely to bend even if it shakes. Therefore, since the starting point of the cleavage is at the end of the scribe line S1, the region including the starting point of the cleavage is less likely to bend and is less likely to be subjected to tensile stress. Therefore, the glass sheet G is less likely to be damaged when transported in a vertical position.

[0071] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention.

[0072] In the above embodiment, the upper end of the first region G1 is held by the gripping pieces 21 of the gripping mechanism 2, but instead, it may be held by another holding member such as a suction cup.

[0073] In the above embodiment, the second region G2 is an unnecessary region having an ear portion Ge, but the second region G2 may also be an unnecessary region without an ear portion Ge, or may be an effective region that will become a product (an effective region with the same plate thickness as the first region G1).

[0074] In the above embodiment, the pushing member 5 and the suction mechanism 6 are used to apply a pushing force to the second region G2 toward the back surface G2b. However, the pushing member 5 may not be used and the suction mechanism 6 may apply a pulling force to the second region G2 toward the back surface G2b. Furthermore, the pushing member 5 and the suction mechanism 6 are used to apply a pushing force to the second region G2 toward the back surface G2b. However, instead of the pushing member, a member that pulls the second region G2 toward the back surface G2b may be used. Alternatively, the upper and lower ends of the second region G2 may be held by holding members such as gripping pieces, and the holding members may be moved toward the back surface G2b, thereby applying a force to the second region G2 toward the back surface G2b.

[0075] In the first embodiment, the suction pressure when the unnecessary region G2 is sucked by the sucking member 62 is set lower as the unnecessary region G2 is located higher in the vertical direction of the glass plate G, thereby causing the upper end region G2U to protrude toward the front surface G2a, and in the third embodiment, the upper end region G1U is caused to protrude toward the front surface G1a by bringing the effective region G1 into contact with the upper convex portion 33 of the back surface support member 3 and the lower convex portion 43 of the pressing member 4, but this is not limiting. The first and third embodiments may be combined to cause the upper end regions G1U and G2U to protrude toward the front surfaces G1a and G2a, respectively.

[0076] In the second embodiment, the suction pressure when the unnecessary region G2 is sucked by the sucking member 62 is set lower as the unnecessary region G2 is located lower in the vertical direction of the glass plate G, thereby causing the lower end region G2L to protrude toward the front surface G2a, and in the fourth embodiment, the effective region G1 is brought into contact with the lower convex portion 35 of the back surface support member 3 and the upper convex portion 45 of the pressing member 4, thereby causing the lower end region G1L to protrude toward the front surface G1a, but this is not limiting. The second embodiment and the fourth embodiment may be combined to cause the lower end regions G1L and G2L to protrude toward the front surfaces G1a and G2a, respectively. [Explanation of symbols]

[0077] 1 Folding device 2 Gripping mechanism 3 Back support member 6 Adsorption mechanism 62 Adsorption member G Plate glass G1 First area (effective area) G1a Surface of the first region G1b Back side of the first area G2 2nd area (unnecessary area) G2a Surface of the second region G2b Back of the second area S scribe line G4 First end surface G5 Second end face S1 Scribe marks

Claims

1. A method for manufacturing a glass plate including a bending and breaking step of bending and breaking a glass plate in a vertical position along a scribe line, The glass plate has a first region and a second region arranged adjacent to each other in the width direction, The scribe line is formed on the front surface side of the glass plate at the boundary between the first region and the second region, In the bending and cutting step, the first region is supported by a back surface support member in contact with the back surface side of the glass plate, while the second region is held by suction from the back surface side by a suction mechanism. In this state, a force is applied to the second region toward the back surface side, thereby cutting out the second region, and A crack is extended from an end of the scribe line as a starting point, the suction mechanism includes a plurality of suction members arranged along the scribe line, In the bending and splitting step, the second region is adsorbed and held from the back surface side by the adsorption member, thereby causing the height position of the starting point of the second region to protrude toward the front surface side.

2. The glass sheet is held at its upper end by a gripping mechanism; The scribe line extends in the vertical direction, The method for manufacturing a glass sheet according to claim 1 , wherein among the plurality of suction members, suction is started in order from the suction member located at the top.

3. 3. The method for manufacturing a glass sheet according to claim 1, wherein the suction pressure of the suction member on the end side protruding toward the front surface is lower than that of the other suction members.

4. In the bending step, the first region and the back surface support member are brought into contact with each other, so that the height position of the first region as the starting point is protruded toward the front surface side.

5. A method for manufacturing a plate glass, comprising a bending and breaking step of bending and breaking a plate glass in a vertical position along a scribe line, The glass plate has a first region and a second region arranged adjacent to each other in the width direction, The scribe line is formed on the front surface side of the glass plate at the boundary between the first region and the second region, In the bending and cutting step, the first region is supported by a back surface support member from the back surface side of the glass plate, and the second region is held by suction from the back surface side by a suction mechanism while the first region is supported by a pressing member from the front surface side of the glass plate. In this state, a force is applied to the second region toward the back surface side to cut out the second region, and A crack is extended from an end of the scribe line as a starting point, One of the rear surface support member and the pressing member has a lower convex portion that protrudes toward the glass plate, A method for manufacturing plate glass, characterized in that in the bending and splitting process, the first region is brought into contact with the back surface support member and the pressing member, thereby causing the height position serving as the starting point in the first region to protrude toward the front surface.

6. A glass sheet manufacturing apparatus including a breaking device that breaks a glass sheet in a vertical position along a scribe line, The glass plate has a first region and a second region arranged adjacent to each other in the width direction, The scribe line is formed on the front surface side of the glass plate at the boundary between the first region and the second region, the breaking device includes a back surface support member that contacts and supports the first region from the back surface side of the glass plate, a suction mechanism that suction-holds the second region from the back surface side, and a pushing member that applies a force to the second region toward the back surface side, The breaking device is configured to extend a crack starting from an end of the scribe line, the suction mechanism includes a plurality of suction members arranged along the scribe line, The suction mechanism is configured to suction-hold the second region from the back surface side using the suction member, thereby causing the height position of the second region that serves as the starting point to protrude toward the front surface side.

7. A plate glass manufacturing apparatus including a bending and breaking device that bends and breaks a vertically oriented plate glass along a scribe line, The glass plate has a first region and a second region arranged adjacent to each other in the width direction, The scribe line is formed on the front surface side of the glass plate at the boundary between the first region and the second region, the breaking device includes a rear surface support member that contacts and supports the first region from the rear surface side of the glass sheet, a pressing member that contacts and supports the second region from the front surface side of the glass sheet, a suction mechanism that suction-holds the second region from the rear surface side, and a pressing member that applies a force to the second region toward the rear surface side, The breaking device is configured to extend a crack starting from an end of the scribe line, One of the rear surface support member and the pressing member has a lower convex portion that protrudes toward the glass plate, The bending and splitting device is characterized in that the height position of the starting point in the first region protrudes toward the front surface side by bringing the first region into contact with the back surface support member.

8. A rectangular glass sheet having two first end faces extending in a sheet drawing direction and two second end faces extending in a width direction intersecting the sheet drawing direction, At least one of the first end surfaces is a cut surface formed by folding and has a scribe line mark, the scribe line has a gap between itself and the second end surface, A glass plate characterized in that a starting point of folding is located at an end of the scribe line.

Images