Method and apparatus for manufacturing glass sheet from glass ribbon

Abstract

An apparatus for manufacturing a glass sheet from a glass ribbon includes a roller for providing the glass ribbon to the apparatus, an actuator configured to bend the glass ribbon along a predetermined cutting path by applying a first average stress and, after nicking the glass ribbon, to further bend a bent portion of the glass ribbon by applying a second average stress, and a nicking device for nicking at least one point of the bent portion of the glass ribbon, wherein the second average stress is greater than the first average stress. According to the configuration described above, a glass sheet without multiple cracks may be manufactured by a simpler process so that glass sheets may be manufactured with high yield and at low cost.

Description

[Rectified under Rule 91, 13.03.2025]METHOD AND APPARATUS FOR MANUFACTURING GLASS SHEET FROM GLASS RIBBON

[0001] The disclosure relates to an apparatus and method for manufacturing a glass sheet from a glass ribbon.

[0002] More particularly, the disclosure relates to an apparatus and method for manufacturing a glass sheet by bending and nicking a glass ribbon.

[0003] Conventionally, a roll-to-sheet (R2S) assembly has been used as a system for manufacturing a glass sheet (or a glass substrate) by cutting an ultrathin glass ribbon (or a glass web). In such roll-to-sheet assemblies according to the related art, a glass ribbon is cut by pressing the glass ribbon with a center bar with constant force along a predetermined broken line path of the glass ribbon and / or scoring the glass ribbon.

[0004] However, a glass ribbon is typically manufactured such that edge portions of opposite sides of the glass ribbon perpendicular to a transfer direction are formed with beads about 2 to 3 times thicker than a quality area that is a middle portion of the glass ribbon between the beads. When stress is applied by applying constant pressure to the glass ribbon in a conventional manner, less internal stress occurs in the quality area that is relatively thin, whereas greater internal stress occurs in the bead portion that is relatively thick. Accordingly, an accurate cut cross-section may not be formed along a predetermined cutting path in the quality area or multiple cracks may be generated in the bead portion.

[0005] Conventionally, a roll-to-sheet (R2S) assembly has been used as a system for manufacturing a glass sheet (or a glass substrate) by cutting an ultrathin glass ribbon (or a glass web). In such roll-to-sheet assemblies according to the related art, a glass ribbon is cut by pressing the glass ribbon with a center bar with constant force along a predetermined broken line path of the glass ribbon and / or scoring the glass ribbon.

[0006] However, a glass ribbon is typically manufactured such that edge portions of opposite sides of the glass ribbon perpendicular to a transfer direction are formed with beads about 2 to 3 times thicker than a quality area that is a middle portion of the glass ribbon between the beads. When stress is applied by applying constant pressure to the glass ribbon in a conventional manner, less internal stress occurs in the quality area that is relatively thin, whereas greater internal stress occurs in the bead portion that is relatively thick. Accordingly, an accurate cut cross-section may not be formed along a predetermined cutting path in the quality area or multiple cracks may be generated in the bead portion.

[0007] These and / or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

[0008] FIG. 1 is a view schematically showing examples of possible cuts of a glass sheet;

[0009] FIG. 2 shows a schematic side view (a) and a schematic front view (b) of a system for manufacturing a glass sheet from a glass ribbon according to the present disclosure;

[0010] FIG. 3 is a top view of a singulation apparatus of FIG. 2 according to the present disclosure;

[0011] FIGs. 4A and 4B are schematic side views of the singulation apparatus of FIG. 2 before bending the glass ribbon and after bending the glass ribbon, respectively, according to the present;

[0012] FIG. 5 is a schematic view showing cutting modes according to a change in displacement of opposite end portions of a center bar in primary bending and secondary bending, in a method of manufacturing a glass sheet from a glass ribbon, according to the present disclosure;

[0013] FIG. 6 is a view showing the stress distribution of a glass ribbon when primary bending is performed on the glass ribbon, according to the present disclosure;

[0014] FIG. 7 is a view showing a change in a radius R of curvature of a bent portion of a glass ribbon according to a change in overhang between a first clamping bar and a second clamping bar in a singulation apparatus according to the present disclosure;

[0015] FIG. 8 is a schematic flowchart of a method of manufacturing a glass sheet from a glass ribbon, according to the present disclosure;

[0016] FIG. 9 is a graph showing crack propagation modes according to an average displacement of a center bar set in primary bending on the Y-axis and secondary bending on the X-axis in a method of manufacturing a glass sheet from a glass ribbon, according to the present disclosure; and

[0017] FIG. 10 is a graph showing a correlation of tensile stress σ on a glass ribbon according to the displacement of a center bar when bending stress is applied to each of two ultrathin glass ribbons having thicknesses of 75 μm and 100 μm, according to the present disclosure.

[0018] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0019] Embodiments of the disclosure will be described below in detail with reference to the accompanying drawings. The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those of ordinary skill in the art. Throughout the drawings, like reference numerals denote like elements. Furthermore, various components and regions in the drawings are schematically illustrated. Accordingly, the present disclosure is not limited by the relative size or distance drawn in the accompanying drawings.

[0020] FIG. 1 is a view schematically showing examples of possible cuts of a glass sheet that may be formed.

[0021] In FIG. 1, (a) shows a case in which multiple cracks are generated in a bead where cutting stress propagation in the transverse direction of a glass ribbon ends, and thus crack branches are formed; (b) shows a case in which cutting is performed well along a certain cutting path; (c) shows a case in which a crack stops prematurely in the opposing bead portion of the transverse cutting path of a glass ribbon; (d) shows a case in which a crack is not propagated straight along the transverse cutting path of a glass ribbon, but is transferred deviated from a crack propagation direction (jog); (e) shows a case in which propagation of a crack stops in the middle; and (f) shows a case in which a crack is not initiated and propagated properly. When cutting such as the cases (a) and (c) to (e) of FIG. 1 occurs, glass sheet manufacturing yield may be reduced, and an additional subsequent process may be necessary, thereby increasing a manufacturing process cost.

[0022] FIG. 2 shows a schematic side view (a) and a schematic front view (b) of a system 200 for manufacturing a glass sheet from a glass ribbon 200 according to embodiments. Referring to FIG. 2, the system 200 according to the present disclosure may include a spool unwinder 220 for unwinding a glass ribbon 210 from a spool, a guide roller 230 for guiding the direction of an unwound glass ribbon and / or holding the unwound glass ribbon, a singulation apparatus 250 for cutting the glass ribbon 210 to manufacture a glass sheet, and an unloader for unloading a cut glass sheet.

[0023] The system 200 according to the present disclosure may further include at least one edge position control (EPC) sensor 240 for detecting and controlling the position of a side surface edge of the glass ribbon 210 between the guide roller 230 and the singulation apparatus 250. Furthermore, the system 200 may further include the unloader (e.g., a vacuum hand) 260 for unloading a cut glass sheet and an interleaf rewinder 270 for rewinding the glass ribbon 210.

[0024] Referring to FIG. 2, the singulation apparatus 250 according to the present disclosure may include a roller 251, at least one actuator 252, and a nicking device 253. The roller 251 may be configured to control the position of the glass ribbon 210 to be provided to the singulation apparatus 250 and maintain the position and tension of the glass ribbon 210 during a cutting process. The roller 251 may be, for example, an edge driven roller (EDR).

[0025] The actuator 252 may be positioned after the roller 251 in a receiving direction of the glass ribbon 210 from the roller 251 and configured to receive the glass ribbon 210 from the roller 251, and perform primary bending on the glass ribbon 210 by applying first average stress to the glass ribbon 210 along a predetermined cutting path. The actuator 252 may be configured to, after nicking at least one point on the predetermined cutting path of the glass ribbon 210, further perform secondary bending on the glass ribbon 210 by applying a second average stress to a bent portion of the glass ribbon 210. In this state, the second average stress applied during the secondary bending may be greater than the first average stress applied during the primary bending.

[0026] The nicking device 253 may be positioned near a first surface of the glass ribbon at the actuator. The nicking device 253 may be configured to nick at least one point of the first surface of the bent portion of the glass ribbon 210. Here, nicking the glass ribbon means generating a defect on the at least one point of the first surface of the glass ribbon. During the secondary bending, the defect will generate a crack exactly at the desired site on the predetermined cutting path of the glass ribbon 210 and allow the crack to propagate along the predetermined cutting path.

[0027] According to some embodiments the singulation apparatus 250 may further include at least one EPC sensor 257 for detecting and controlling the side surface edge position of the glass ribbon 210 between the roller 251 and the actuator 252.

[0028] The primary bending for applying weak stress to the predetermined cutting path of the glass ribbon 210 may generate a basic stress field in the cutting path of the glass ribbon 210 before performing nicking, thereby forming a straight guideline for propagating a crack generated later in the secondary bending. Nicking at least one point of the cutting path of the glass ribbon 210 generates a defect in the glass ribbon 210 from which a crack is initiated during the secondary bending. During the secondary bending, in which greater stress is applied than that in the primary bending, a crack is initiated from the nicked portion that is weakened by the defect, and thus the crack may be propagated straight along the guideline formed during the primary bending, thereby minimizing generation of multiple cracks in the bead portion. Accordingly, final cutting may be performed after the secondary bending so that when a glass sheet is manufactured, manufacturing yield may be improved in a simple process.

[0029] According to some embodiments, the actuator 252 may further include a center bar 254 positioned near a second surface of the glass ribbon at the actuator 252 and at least two clamping bars 255 and 256 positioned near the first surface of the glass ribbon at the actuator. The center bar 254 may bend the glass ribbon 210 by applying stress to the glass ribbon 210 along the predetermined cutting path in a direction transverse to the receiving direction of the glass ribbon 210 from the roller 251, and thus tensile stress may be generated so that a crack may be propagated along the cutting path.

[0030] The at least two clamping bars 255 and 256 may be positioned near the first surface of the glass ribbon 210 and include a first clamping bar 255 and a second clamping bar 256. The clamping bars may hold the glass ribbon 210 and / or isolate the bent portion with the center bar 254. FIG. 3 is a top view of the singulation apparatus 250 of FIG. 2 according to the present disclosure, and FIGs. 4A and 4B are schematic side views of the singulation apparatus of FIG. 2 before bending the glass ribbon and after bending the glass ribbon, respectively, according to the present disclosure.

[0031] Referring to FIG. 3, the actuator 252 may include two or more sub-actuators, and may include, for example, two servo motors. As illustrated in FIG. 3, when two sub-actuators (e.g., servo motor) 252 are used, the two sub-actuators 252 may be respectively connected to a first and a second end portions of the center bar 254 and move respectively the first and second end portions of the center bar 254 perpendicularly to the receiving direction of the glass ribbon from the roller 251. The first and second sub-actuators, during bending of the glass ribbon 210, may move the first and second end portions of the center bar 254 perpendicularly to the receiving direction of the glass ribbon toward the first surface of the glass ribbon 210 and make respectively different displacements to the first and second end portions of the center bar 254. This separate movements of the first and second end portions of the center bar 254 allow different levels of stresses to be applied to the first and second end portions of the glass ribbon 210 along the predetermined cutting path.

[0032] In FIGs. 4A and 4B, a first clamping bar 255 of the at least two clamping bars 255 and 256 is located before the center bar 254 in the receiving direction of the glass ribbon 210. A second clamping bar 256 of the at least two clamping bars 255 and 256 is located after the center bar 254 in the receiving direction of the glass ribbon 210, as shown in Fig. 2 and 4. Fig. 4A shows that the center bar 254 move to contact the second surface of the glass ribbon 210 in a direction from the second surface to the first surface of the glass ribbon 210 and the clamping bars 255 and 256 move to contact the first surface of the glass ribbon 210 in a direction from the first surface and to the second surface of the glass ribbon 210. In Fig. 4A, the displacement (d) of the glass ribbon 210 in the direction toward the clamping bars 255 and 256 will be 0 mm. The displacement (d) may affect the stress applied for bending. When the displacement (d) is too small, a crack may not be propagated sufficiently, and when the displacement (d) is too large, multiple cracks may be generated in the glass ribbon 210, in particular in the bead portion thereof. When the actuator 252 performs primary bending on the glass ribbon 210, the actuator 252 may apply first average stress to the glass ribbon 210 by moving the center bar and the at least two clamping bars so that the glass ribbon is bent by a first average displacement from a position of the receiving glass ribbon in a direction of from the second surface to the first surface. When the actuator 252 performs secondary bending on the glass ribbon 210, the actuator 252 may apply second average stress to the glass ribbon 210 by moving the center bar so that the glass ribbon is bent by a second average displacement from the position of the receiving glass ribbon in the direction of from the second surface to the first surface. The second average displacement may be greater than the first average displacementA.

[0033] An overhang is a distance between a center of the first clamping bar 255 and a center of the second clamping bar 256, as indicated by OH in FIGs. 4A and 4B. As the overhang increases, a process window that is tolerant with respect to the process may be widened. However, as the overhang decreases, the curvature of the bent portion of the glass ribbon 210 is affected during bending and the applied stress to the glass ribbon increases.

[0034] According to some embodiments, the nicking device 253 may include, for example, at least one of a cutting wheel or a laser device, but the disclosure is not limited thereto and any device capable of generating a nick on the glass ribbon 210 may be used therefor. Furthermore, the nicking device 253 may be connected to another actuator (e.g., a servo motor) to move the nicking device to another position along the predetermined cutting path of the glass ribbon 210.

[0035] FIG. 5 is a schematic view showing the cutting modes according to a change in the displacements of the opposite end portions of the center bar 254 during the primary bending and the secondary bending, in a method of manufacturing a glass sheet from a glass ribbon, according to the present disclosure. Referring to FIGS. 2 and 5, according to some embodiments, during the primary bending, the center bar 254 is set to have the displacement H1Fof one end portion less than the displacement H1Rof the other end portion so as to asymmetrically press forward the glass ribbon 210 in a direction toward the clamping bars 255 and 256, and thus stress applied to one end portion of a predetermined cutting path of the glass ribbon 210 may be less than the stress applied to the other end portion thereof.

[0036] Furthermore, during the secondary bending, reversely, the displacement H1F'of one end portion of the center bar 254 is set to be greater than the displacement H1R'of the other end portion so that the center bar 254 asymmetrically presses forward the glass ribbon 210 in the direction toward the clamping bars 255 and 256, and thus, stress applied to the one end portion of the predetermined cutting path of the glass ribbon 210 may be greater than the stress applied to the other end portion thereof. In this case, at least a point of the bent portion of the glass ribbon 210 where nicking is performed may be the one end portion of the glass ribbon 210. For example, during the primary bending, with the displacement dFof the front end portion of the center bar 254 set to be 0.8 mm and the displacement dRof the rear end portion of the center bar 254 set to be 1.2 mm, the center bar 254 may press forward the glass ribbon 210 in the direction toward the clamping bars 255 and 256, and during the secondary bending, with the displacement H1F'of the front end portion of the center bar 254 set to be 2.8 mm and the displacement H1R'of the rear end portion of the center bar 254 set to be 1.2 mm, the center bar 254 may press forward the glass ribbon 210 in the direction toward the clamping bars 255 and 256. According to the configuration as above, as a nick is generated in the one end portion of the cutting path of the glass ribbon 210, a defect is formed, but the defect does not initiate a crack, and during the secondary bending, when the propagation of a crack is initiated. The displacement dR'of the other end portion of the center bar 254 is set to be smaller than the displacement d1F'. Thus, less stress is applied to the corresponding second end of the glass ribbon contacting the other end portion of the center bar 254 than the corresponding first end of the glass ribbon contacting the one end portion of the center bar 254 along the predetermined cutting path. In this case, the internal stress applied to the bead of the second side edge end portion of the glass ribbon may be reduced, thereby minimizing multiple cracks on the bead.

[0037] FIG. 6 is a view showing the stress distribution of the glass ribbon 210 when the primary bending is performed on the glass ribbon 210, according to the present disclosure.

[0038] In FIG. 6, during the primary bending, the stress applied to beads 212 and 216 of edges of the glass ribbon 210 is greater than the stress applied to a quality area 214 that is a middle portion of the glass ribbon 210.

[0039] FIG. 6 shows a stress distribution when asymmetrical stress is applied by applying a greater stress to the bead portion 216 at the other end portion of the glass ribbon than the bead 212 at the one end portion of the bend portion of the glass ribbon 210 during the primary bending according to some embodiments. Accordingly, the bead portion at the other end portion of the glass ribbon shows the maximum stress STmax.

[0040] FIG. 7 is a view showing a change in a radius R of curvature of the bent portion of the glass ribbon 210 according to a change in overhang OH in the singulation apparatus 250 according to the present disclosure. In FIG. 7, according to some embodiments, the displacement of the center bar 254 and the displacements of the clamping bars 255 and 256 are set to the same condition in (a) and (b), and only the overhang between the first clamping bar 255 and the second clamping bar 256 is set to 40 mm in (a) and 30 mm in (b), respectively. Then, the radius R of the curvature of the bent portion of the glass ribbon 210 becomes R1= 192.5 mm in (a) and R2= 105 mm in (b), In this case, a bending level of (b) is greater than that of (a). Accordingly, the applied stress increases as the overhang decreases. In contrast, as the overhang increases, the process window with respect to a thickness change of the glass ribbon may be widened.

[0041] However, as the overhang OH affects the curvature of the bent portion of the glass ribbon 210 during bending, thereby affecting the applied stress to the bent portion of the glass ribbon 210. Referring to Figs. 6 and 7, when the overhang OH increases more than 40 mm, the quality area 214, which exists between the beads 212 of both edges in a width direction of the glass ribbon 210, does not receive enough stress to propagate a crack. Accordingly, the overhang OH may be in a range from 0 mm to 40mm, a range from 10 mm to 40 mm, a range from 20 mm to 40 mm, a range from 28 mm to 40 mm, or a range from 32 mm to 40 mm. By way of example, in the case that the thickness of the glass ribbon 210 is 75 micrometers (μm), the widest process window is obtainable when the overhang is in a range from 28 mm to 40 mm. In the case that the thickness of the glass ribbon is 100 μm, the widest process window is obtainable when the overhang is in a range from 32 mm to 40 mm.

[0042] FIG. 8 is a schematic flowchart of a method of manufacturing a glass sheet from a glass ribbon, according to the present disclosure. According to some embodiments, the method of manufacturing a glass sheet from a glass ribbon may include providing the singulation apparatus 250 with the glass ribbon 210 in operation S810; performing primary bending on the glass ribbon 210 along a predetermined cutting path thereof by applying a first average stress thereto S820; nicking at least one point of the bent portion of the glass ribbon 210 using the nicking device 253 S830; and performing secondary bending on the bent portion of the glass ribbon 210 by applying a second average stress thereto S840.

[0043] The second average stress may be greater than the first average stress. The method may further include cutting a secondary bent portion of the glass ribbon 210 S850. Referring to FIGS. 2 and 8, in operation S810, the glass ribbon 210 may be provided from the spool unwinder 220 to the singulation apparatus 250 through the guide roller 230, and during a cutting process the position and tension of the glass ribbon 210 may be maintained. In this state, the glass ribbon 210 is provided to a space between the center bar 254 and the at least two clamping bars 255 and 256.

[0044] In operation S820, the center bar 254 is set to have the first average displacement H11and presses the glass ribbon 210 toward the clamping bars 255 and 256, applying stress to the glass ribbon, thereby performing primary bending. According to some embodiments, in operation S820, during the primary bending, the center bar 254 may apply stress, for bending, to one end portion (e.g., the front end portion) of the predetermined cutting path of the glass ribbon 210 that is less than the stress applied to the other end portion (e.g., the rear end portion) of the predetermined cutting path.

[0045] In operation S830, at least one point of the bent portion of the glass ribbon 210 may be nicked using the nicking device 253. For example, at least one of a cutting wheel or a laser device may be used as the nicking device 253, but the disclosure is not limited thereto. For example, at least one of a cutting wheel or a laser device may be used as the nicking device 253, but the disclosure is not limited thereto.

[0046] In operation S840, the center bar 254 moves by the second average displacement and pressurizes the glass ribbon 210 toward the clamping bars 255 and 256, applying stress to the glass ribbon, thereby performing secondary bending. According to some embodiments, in operation S840, during the secondary bending, the center bar 254 may apply stress, for bending, to the one end portion (e.g., the front end portion) of the predetermined cutting path of the glass ribbon 210 that is greater than the stress applied to the other end portion (e.g., the rear end portion) of the predetermined cutting path. During the secondary bending, a crack may be propagated from the bead at the one end portion to the other bead portion at the other end portion of the predetermined cutting path of the glass ribbon 210. Then, in operation S850, cutting along the predetermined cutting path of the glass ribbon 210 may be performed. During the operation S850, the glass ribbon 210 may be cut along the predetermined cutting path by applying greater stress to the glass ribbon 210 through the center bar 254 than the stress applied to the glass ribbon 210 during operation S840 for the secondary bending of the glass ribbon 210.

[0047] FIG. 9 is a graph schematically showing crack propagation modes according to the average displacement H1of the center bar 254 set in the primary bending on a Y-axis and the secondary bending on an X-axis in a method of manufacturing a glass sheet from a glass ribbon. FIG. 9 shows results of crack propagation modes with respect to the coordinates of a Y-axis indicating the displacement of a center bar in the primary bending and an X-axis indicating the displacement of a center bar in the secondary bending, for a glass ribbon in which the quality area in the middle of the ribbon has a 100 μm thickness.

[0048] In the case of FIG. 9, a crack is generated from when the center bar displacement d of the Y-axis in the primary bending is about 0.8 mm. However, as multiple cracks M.C. may also be generated, it may be appropriate that the displacement d is about 1.0 mm or more.

[0049] Furthermore, when the center bar displacement d of the Y-axis in the primary bending exceeds 1.4 mm, a crack is initiated without the secondary bending so that the displacement d of 1.4 mm or less may be appropriate. In addition, it may be seen that the displacement d of the center bar of the X-axis in the secondary bending may be 0.8 mm or more at which generation of a crack is stopped, and it may be appropriate that the displacement is set to 1.8 mm or less at which multiple cracks are generated.

[0050] FIG. 10 is a graph showing a correlation of tensile stress σ generated in each of two glass ribbons having thicknesses of 75 μm and 100 μm according to the displacement of the center bar 254 when bending stress is applied to each of the glass ribbons, according to the present disclosure. The graphs of FIG. 10 show different stresses generated in the beads located at both side edge portions of each of the two glass ribbons and the quality area 214, which is a middle portion between the beads 212 and 216. In the singulation apparatus 250 according to some embodiments, when a glass ribbon having a thickness of 75 μm is pressed and bent while the average displacementd of the center bar 254 is set to 1 mm, the maximum bending stress σmaxof the quality area that is a middle portion is 20.0 Mpa and the maximum bending stress σmaxof the bead area is 60.0 Mpa. Furthermore, when a glass ribbon having a thickness of 100 μm is pressed and bent while the average displacement daverageof the center bar 254 is set to 0.75 mm, the maximum bending stress σmaxof the quality area that is a middle portion is 20.0 Mpa and the maximum bending stress σmaxof the bead area is 60.0 Mpa.

[0051] It is seen that when the bending stress σmaxapplied to the quality area of a glass ribbon exceeds 20.0 Mpa (in this case, the maximum bending stress σmaxof the bead area may be 60.0 Mpa), a crack may be initiated and start to propagate along the predetermined cutting path of the glass ribbon 210, transverse to the receiving direction of the glass ribbon 210. In this state, the average displacement of the center bar 254 on the graph is between about 0.75 mm and about 1 mm.

[0052] Furthermore, when the bending stress σmaxapplied to the bead area of the glass ribbon is greater than 100 Mpa, multiple cracks and multiple chips may be generated in the bead area. Accordingly, it is seen that, in order to prevent the generation of multiple cracks and chips and the propagation of a crack by generating appropriate tensile stress σ in the bead area of the glass ribbon, stress of about 60 MPa to about 100 MPa is applied to the bead area.

[0053] The range of the average displacement daof the center bar 254 used to apply bending stress corresponding thereto is about 1 mm to about 1.7 mm for a glass ribbon having a thickness of 75 μm and about 0.75 mm to about 1.25 mm for a glass ribbon having a thickness of 100 μm.

[0054] According to the method of manufacturing a glass sheet from a glass ribbon in FIG. 8, the internal stress generated in the beads 212 of the glass ribbon is in a range of about 60 Mpa to about 100 Mpa during at least one of the primary bending operation S820 and the secondary bending operation S840.

[0055] When a glass sheet is manufactured from a glass ribbon according to the present disclosure, a glass sheet without multiple cracks may be manufactured by a simplified and efficient process with high yield and at low cost.

[0056] While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.

Claims

1.An apparatus for manufacturing a glass sheet from a glass ribbon, comprising:a roller;an actuator positioned after the roller in a receiving direction of the glass ribbon from the roller, the actuator being configured to receive the glass ribbon from the roller, bend the glass ribbon along a predetermined cutting path transverse to the receiving direction of the glass ribbon by applying a first average stress and, after nicking the glass ribbon, further bend a bent portion of the glass ribbon by applying a second average stress; anda nicking device positioned near a first surface of the glass ribbon at the actuator and configured to nick at least one point of the first surface of the bent portion of the glass ribbon;wherein the second average stress is greater than the first average stress.2.The apparatus of claim 1,wherein the actuator comprises a center bar positioned near a second surface of the glass ribbon and at least two clamping bars positioned near the first surface of the glass sheet, the second surface of the glass ribbon being opposite to the first surface of the glass ribbon.wherein, when bending the glass ribbon, the actuator applies the first average stress to the glass ribbon by moving the center bar and the at least two clamping bars so that the glass ribbon is bent by a first average displacement from a position of the receiving glass ribbon in a direction of from the second surface to the first surface, ,wherein, when further bending the bent portion of the glass ribbon, the actuator applies the second average stress to the bent portion of the glass ribbon by moving the center bar and the at least two clamping bars so that the glass ribbon is bent by a second average displacement from the position of the receiving glass ribbon in the direction of from the second surface to the first surface, andwherein the second average displacement is greater than the first average displacement.3.The apparatus of claim 2,wherein a first clamping bar of the at least two clamping bars is located before the center bar in the receiving direction of the glass ribbon at the actuator, and a second clamping bar of the at least two clamping bars is located after the center bar in the receiving direction of the glass ribbon at the actuator,wherein, when bending the glass ribbon, the center bar moves perpendicularly to the receiving direction of the glass ribbon toward the first surface of the glass ribbon to contact and pressurize the predetermined cutting path of the second surface of the glass ribbon so that the glass ribbon is bent by a first average displacement from a position of the receiving glass ribbon toward the first surface, the at least two clamping bars moving perpendicularly to the receiving direction of the glass ribbon toward the second surface of the glass ribbon to hold the glass ribbon, andwherein, when further bending the bent portion of the glass ribbon, the center bar moves perpendicularly to the receiving direction of the glass ribbon toward the first surface of the glass ribbon to contact and pressurize the predetermined cutting path of the second surface of the glass ribbon so that the glass ribbon is bent by a second average displacement from a position of the receiving glass ribbon toward the first surface, the at least two clamping bars moving perpendicularly to the receiving direction of the glass ribbon toward the second surface of the glass ribbon to hold the glass ribbon.4.The apparatus of claim 1, wherein, when bending the glass ribbon along the predetermined cutting path, the actuator applies smaller stress to a first end of the predetermined cutting path than a second end of the predetermined cutting path.5.The apparatus of claim 4, wherein, when further bending the bent portion of the glass ribbon, the actuator applies greater stress to the first end of the predetermined cutting path of the glass ribbon than the second end of the predetermined cutting path of the glass ribbon.6.The apparatus of claim 2 or 3, wherein, when bending the glass ribbon, a first end of the center bar, in a direction transverse to the receiving direction of the glass ribbon, has a smaller displacement in a direction from the second surface to the first surface than a second end of the center bar.7.The apparatus of claim 6, wherein, when further bending the bent portion of the glass ribbon, the first end of the center bar, in a direction transverse to the receiving direction of the glass ribbon, has a greater displacement in a direction from the second surface to the first surface than the second end of the center bar.8.The apparatus of claim 1, wherein the at least one point of the bent portion to be nicked by the nicking device is located on one end of the predetermined cutting path of the first surface of the glass ribbon.9.The apparatus claim 3, wherein a distance between a center of the first clamping bar and a center of the second clamping bar is greater than 0 millimeter but less than or equal to 40 millimeters.10.The apparatus claim 1, wherein the nicking device comprises at least one of a cutting wheel or a laser device.11.A method of manufacturing a glass sheet from a glass ribbon, the method comprising:bending the glass ribbon along a predetermined cutting path with a singulation apparatus by applying a first average stress;nicking at least one point of the predetermined cutting path of a first surface of the glass ribbon;further bending a bent portion of the glass ribbon by applying a second average stress,wherein the second average stress is greater than the first average stress.12.The method of claim 11, wherein the singulation apparatus comprises an actuator which comprises a center bar positioned near a second surface of the glass ribbon and at least two clamping bars positioned near the first surface of the glass sheet, the second surface of the glass ribbon being opposite to the first surface of the glass ribbonwherein bending the glass ribbon along a predetermined cutting path comprises applying the first average stress to the glass ribbon by moving the center bar and the at least two clamping bars so that the glass ribbon is bent by a first average displacement from a position of the receiving glass ribbon in a direction of from the second surface to the first surface,wherein the further bending of the bent portion of the glass ribbon comprises applying the second average stress to the bent portion of the glass ribbon by moving the center bar and the at least two clamping bars so that the glass ribbon is bent by a second average displacement from the position of the receiving glass ribbon in the direction of from the second surface to the first surface, andwherein the second average displacement is greater than the first average displacement.13.The method of claim 12, wherein a first clamping bar of the at least two clamping bars is located before the center bar in the receiving direction of the glass ribbon at the actuator, and a second clamping bar of the at least two clamping bars is located after the center bar in the receiving direction of the glass ribbon at the actuator,wherein bending the glass ribbon comprises applying the first average stress to the glass ribbon by moving the center bar perpendicularly to the receiving direction of the glass ribbon toward the first surface of the glass ribbon to contact and pressurize the predetermined cutting path of the second surface of the glass ribbon so that the glass ribbon is bent by a first average displacement from a position of the receiving glass ribbon toward the first surface, and moving the at least two clamping bars perpendicularly to the receiving direction of the glass ribbon toward the second surface of the glass ribbon to hold the glass ribbon,wherein further bending the bent portion of the glass ribbon comprises applying the second average stress to the bent portion of the glass ribbon by moving the center bar perpendicularly to the receiving direction of the glass ribbon toward the first surface of the glass ribbon to contact and pressurize the predetermined cutting path of the second surface of the glass ribbon so that the glass ribbon is bent by a second average displacement from a position of the receiving glass ribbon toward the first surface, and moving the at least two clamping bars perpendicularly to the receiving direction of the glass ribbon toward the second surface of the glass ribbon to hold the glass ribbon.14.The method of claim 11, wherein bending the glass ribbon comprises applying smaller stress to a first end of the predetermined cutting path of the glass ribbon than a second end of the predetermined cutting path.15.The method of claim 14, wherein further bending the bent portion of the glass ribbon comprises applying greater stress to the first end of the predetermined cutting path of the glass ribbon than the second end of the predetermined cutting path of the glass ribbon.16.The method of claim 12, wherein while bending the glass ribbon, a first end of the center bar, in a direction transverse to the receiving direction of the glass ribbon, has a smaller displacement in a direction from the second surface to the first surface than a second end of the center bar.17.The method of claim 16, wherein while further bending the bent portion of the glass ribbon, the first end of the center bar, in a direction transverse to the receiving direction of the glass ribbon, has a greater displacement in a direction from the second surface to the first surface than the second end of the center bar.18.The method of claim 11 , wherein the at least one point of the bent portion to be nicked is located on one end of the predetermined cutting path of the first surface of the glass ribbon.19.The method of claim 11, wherein at least one of bending the glass ribbon and further bending the bent portion of the glass ribbon comprise creating an internal stress of at least 60 Mpa but less than 100 Mpa in bead areas of the glass ribbon.20.The method of claim 13, wherein a distance between a center of the first clamping bar and a center of the second clamping bar is greater than 0 millimeter but less than or equal to 40 millimeters.

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