Apparatus and method to form thin glass

Abstract

An apparatus and method for manufacturing a glass article includes forming a glass ribbon from a glass delivery device, the glass ribbon extending in a widthwise direction below the glass delivery device and including a first edge region, a central region, and a second edge region in the widthwise direction where each of the first edge region and the second edge region of the glass ribbon is contacted with a pair of edge rolls proximate the glass delivery device.

Description

PPARATUS AND METHOD TO FORM THIN GLASSCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63 / 592678 filed on October 24, 2023, the content of which is relied upon and incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates generally to an apparatus and method to form thin glass and more specifically an apparatus and method to form ultra-thin bendable glass.BACKGROUND

[0003] In the production of glass articles, such as glass sheets for display applications, including televisions and hand-held devices, such as telephones and tablets, molten glass can be formed into glass sheets by flowing the molten glass into a glass ribbon from a forming device. Depending on the glass composition and the desired thickness of the glass, significant challenges may exist in producing glass sheets with acceptable characteristics, such as thickness uniformity. In addition, the width of the glass ribbon tends to contract below the forming device, a phenomenon commonly referred to as ribbon width attenuation. Such attenuation not only reduces the volume of usable glass from a given process but can also adversely affect characteristics such as thickness uniformity. Accordingly, it would be desirable to produce glass sheets, such as increasingly wide and thin glass sheets, with relatively uniform thickness from a variety of different glass compositions.S MMARY

[0004] Embodiments disclosed herein include a method of manufacturing a glass article. The method includes forming a glass ribbon from a glass delivery device. The glass ribbon extends in a widthwise direction below the glass delivery device and includes a first edge region, a central region, and a second edge region in the widthwise direction. The method also includes contacting each of the first edge region and the second edge region of the glass ribbon with a pair of edge rolls proximate the glass delivery device.

[0005] Embodiments disclosed herein also include an apparatus for manufacturing a glass article. The apparatus includes a glass delivery device extending in a widthwise direction andincluding a first edge region, a central region, and a second edge region. The apparatus also includes a pair of edge rolls proximate the glass delivery device and a pair of opposing movable coplanar plates proximate the pair of edge rolls.

[0006] Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the disclosed embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0007] It is to be understood that both the foregoing general description and the following detailed description present embodiments intended to provide an overview or framework for understanding the nature and character of the claimed embodiments. The accompanying drawings are included to provide further understanding and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic view of a glass making apparatus and process;

[0009] FIG. 2 is a schematic perspective end view of a glass manufacturing apparatus that includes a delivery device having a delivery orifice;

[0010] FIG. 3 is schematic perspective side view of a portion of the glass manufacturing apparatus of FIG. 2;

[0011] FIG. 4 is schematic bottom view of an example glass manufacturing apparatus that includes edge rolls and movable coplanar plates in accordance with embodiments herein;

[0012] FIG. 5 is a schematic perspective end view of the example glass manufacturing apparatus of FIG. 4;

[0013] FIG. 6 is a schematic perspective side view of the example glass manufacturing apparatus of FIGS. 4 and 5;

[0014] FIG. 7 is bottom cutaway view of an example glass ribbon in accordance with embodiments disclosed herein;

[0015] FIG. 8 is a side cutaway view of an example edge roll in accordance with embodiments disclosed herein;

[0016] FIG. 9 is a schematic perspective end view of an example glass manufacturing apparatus in accordance with embodiments disclosed herein; and

[0017] FIG. 10 is a schematic perspective end view of an example glass manufacturing apparatus in accordance with embodiments disclosed herein.DETAILED DESCRIPTION

[0018] Reference will now be made in detail to the present preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0019] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, for example by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0020] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0021] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0022] As used herein, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0023] As used herein, the term “molten glass” refers to a glass composition that is at or above its liquidous temperature (the temperature above which no crystalline phase can coexist in equilibrium with the glass).

[0024] As used herein, the term “liquidous viscosity” refers to the viscosity of a glass composition at its liquidous temperature.

[0025] As used herein, the term “proximate the delivery orifice” refers to a distance that is less than or equal to about 50 millimeters to at least a portion of a delivery orifice of a glass delivery device.

[0026] As used herein, the term “near the first edge region” of a glass ribbon refers to a position closer to a first edge of a glass ribbon in its widthwise direction than a central region or a second edge of the glass ribbon in its widthwise direction.

[0027] As used herein, the term “near the second edge region” of a glass ribbon refers to a position closer to a second edge of a glass ribbon in its widthwise direction than a central region or a first edge of the glass ribbon in its widthwise direction.

[0028] As used herein, the term “near the central region” of a glass ribbon refers to a position closer to a central region of a glass ribbon in its widthwise direction than a first edge or a second edge of the glass ribbon in its widthwise direction.

[0029] As used herein, the term “thermally conductive” refers to a material having a thermal conductivity of greater than or equal to about 10 W / m-K at 25 °C.

[0030] As used herein, the term “relatively farther” refers to a distance that is at least twice as far from an object, device, or region as a distance that is “relatively closer” to that object, device, or region.

[0031] Shown in FIG. 1 is an exemplary glass manufacturing apparatus 10. In some examples, the glass manufacturing apparatus 10 can comprise a glass melting furnace 12 that can include a melting vessel 14. In addition to melting vessel 14, glass melting furnace 12 includes one or more additional components, such as heating elements (as will be described in more detail herein) that heat raw materials and convert the raw materials into molten glass. In further examples, glass melting furnace 12 may include thermal management devices (e.g., insulation components) that reduce heat lost from a vicinity of the melting vessel. In still further examples, glass melting furnace 12 may include electronic devices and / orelectromechanical devices that facilitate melting of the raw materials into a glass melt. Still further, glass melting furnace 12 may include support structures (e.g., support chassis, support member, etc.) or other components.

[0032] Glass melting vessel 14 is typically comprised of refractory material, such as a refractory ceramic material, for example a refractory ceramic material comprising alumina or zirconia. In some examples glass melting vessel 14 may be constructed from refractory ceramic bricks. Specific embodiments of glass melting vessel 14 will be described in more detail below.

[0033] In some examples, the glass melting furnace may be incorporated as a component of a glass manufacturing apparatus to fabricate a glass substrate, for example a glass ribbon of a continuous length. In some examples, the glass melting furnace of the disclosure may be incorporated as a component of a glass manufacturing apparatus comprising a slot draw apparatus, a float bath apparatus, a down-draw apparatus such as a fusion process, an up- draw apparatus, a press-rolling apparatus, a tube drawing apparatus or any other glass manufacturing apparatus that would benefit from the aspects disclosed herein.

[0034] The glass manufacturing apparatus 10 can optionally include an upstream glass manufacturing apparatus 16 that is positioned upstream relative to glass melting vessel 14. In some examples, a portion of, or the entire upstream glass manufacturing apparatus 16, may be incorporated as part of the glass melting furnace 12.

[0035] As shown in the illustrated example, the upstream glass manufacturing apparatus 16 can include a storage bin 18, a raw material delivery device 20 and a motor 22 connected to the raw material delivery device. Storage bin 18 may be configured to store a quantity of raw batch materials 24 that can be fed into melting vessel 14 of glass melting furnace 12, as indicated by arrow 26. Raw batch materials 24 typically comprise one or more glass forming metal oxides and one or more modifying agents. In some examples, raw material delivery device 20 can be powered by motor 22 such that raw material delivery device 20 delivers a predetermined amount of raw batch materials 24 from the storage bin 18 to melting vessel 14. In further examples, motor 22 can power raw material delivery device 20 to introduce raw batch materials 24 at a controlled rate based on a level of molten glass sensed downstream from melting vessel 14. Raw batch materials 24 within melting vessel 14 can thereafter be heated to form molten glass 28.

[0036] Glass manufacturing apparatus 10 can also optionally include a downstream glass manufacturing apparatus 30 positioned downstream relative to glass melting furnace 12. In some examples, a portion of downstream glass manufacturing apparatus 30 may beincorporated as part of glass melting furnace 12. In some instances, first connecting conduit 32 discussed below, or other portions of the downstream glass manufacturing apparatus 30, may be incorporated as part of glass melting furnace 12. Elements of the downstream glass manufacturing apparatus, including first connecting conduit 32, may be formed from a precious metal. Suitable precious metals include platinum group metals selected from the group of metals consisting of platinum, iridium, rhodium, osmium, ruthenium and palladium, or alloys thereof. For example, downstream components of the glass manufacturing apparatus may be formed from a platinum -rhodium alloy including from about 100% to about 60% by weight platinum and about 0% to about 40% by weight rhodium. However, other suitable metals can include molybdenum, rhenium, tantalum, titanium, tungsten and alloys thereof. Oxide Dispersion Strengthened (ODS) precious metal alloys are also possible.

[0037] Downstream glass manufacturing apparatus 30 can include a first conditioning (i.e., processing) vessel, such as fining vessel 34, located downstream from melting vessel 14 and coupled to melting vessel 14 by way of the above-referenced first connecting conduit 32. In some examples, molten glass 28 may be gravity fed from melting vessel 14 to fining vessel 34 by way of first connecting conduit 32. For instance, gravity may cause molten glass 28 to pass through an interior pathway of first connecting conduit 32 from melting vessel 14 to fining vessel 34. It should be understood, however, that other conditioning vessels may be positioned downstream of melting vessel 14, for example between melting vessel 14 and fining vessel 34. In some embodiments, a conditioning vessel may be employed between the melting vessel and the fining vessel wherein molten glass from a primary melting vessel is further heated to continue the melting process or cooled to a temperature lower than the temperature of the molten glass in the melting vessel before entering the fining vessel.

[0038] Bubbles may be removed from molten glass 28 within fining vessel 34 by various techniques. For example, raw batch materials 24 may include multivalent compounds (i.e. fining agents) such as tin oxide that, when heated, undergo a chemical reduction reaction and release oxygen. Other suitable fining agents include without limitation arsenic, antimony, iron and cerium. Fining vessel 34 is heated to a temperature greater than the melting vessel temperature, thereby heating the molten glass and the fining agent. Oxygen bubbles produced by the temperature-induced chemical reduction of the fining agent(s) rise through the molten glass within the fining vessel, wherein gases in the molten glass produced in the melting furnace can diffuse or coalesce into the oxygen bubbles produced by the fining agent. The enlarged gas bubbles can then rise to a free surface of the molten glass in the finingvessel and thereafter be vented out of the fining vessel. The oxygen bubbles can further induce mechanical mixing of the molten glass in the fining vessel.

[0039] Downstream glass manufacturing apparatus 30 can further include another conditioning vessel such as a mixing vessel 36 for mixing the molten glass. Mixing vessel 36 may be located downstream from the fining vessel 34. Mixing vessel 36 can be used to provide a homogenous glass melt composition, thereby reducing cords of chemical or thermal inhomogeneity that may otherwise exist within the fined molten glass exiting the fining vessel. As shown, fining vessel 34 may be coupled to mixing vessel 36 by way of a second connecting conduit 38. In some examples, molten glass 28 may be gravity fed from the fining vessel 34 to mixing vessel 36 by way of second connecting conduit 38. For instance, gravity may cause molten glass 28 to pass through an interior pathway of second connecting conduit 38 from fining vessel 34 to mixing vessel 36. It should be noted that while mixing vessel 36 is shown downstream of fining vessel 34, mixing vessel 36 may be positioned upstream from fining vessel 34. In some embodiments, downstream glass manufacturing apparatus 30 may include multiple mixing vessels, for example a mixing vessel upstream from fining vessel 34 and a mixing vessel downstream from fining vessel 34. These multiple mixing vessels may be of the same design, or they may be of different designs.

[0040] Downstream glass manufacturing apparatus 30 can further include another conditioning vessel such as delivery vessel 40 that may be located downstream from mixing vessel 36. Delivery vessel 40 may condition molten glass 28 to be fed into a downstream forming device. For instance, delivery vessel 40 can act as an accumulator and / or flow controller to adjust and / or provide a consistent flow of molten glass 28 to forming body 42 by way of exit conduit 44. As shown, mixing vessel 36 may be coupled to delivery vessel 40 by way of third connecting conduit 46. In some examples, molten glass 28 may be gravity fed from mixing vessel 36 to delivery vessel 40 by way of third connecting conduit 46. For instance, gravity may drive molten glass 28 through an interior pathway of third connecting conduit 46 from mixing vessel 36 to delivery vessel 40.

[0041] Downstream glass manufacturing apparatus 30 can further include forming apparatus 48 comprising the above-referenced glass delivery device 42 and inlet conduit 50. Exit conduit 44 can be positioned to deliver molten glass 28 from delivery vessel 40 to inlet conduit 50 of forming apparatus 48. For example, exit conduit 44 may be nested within and spaced apart from an inner surface of inlet conduit 50, thereby providing a free surface of molten glass positioned between the outer surface of exit conduit 44 and the inner surface of inlet conduit 50. Glass delivery device 42 can comprise a delivery orifice (e.g., delivery slot142 as shown in FIG. 3) through which molten glass flows to produce a single glass ribbon 58 that is drawn in a draw or flow direction 60 by applying tension to the glass ribbon, such as by gravity, edge rolls 72 and pulling rolls 82, to control the dimensions of the glass ribbon as the glass cools and a viscosity of the glass increases. Accordingly, glass ribbon 58 goes through a visco-elastic transition and acquires mechanical properties that give the glass ribbon 58 stable dimensional characteristics. Glass ribbon 58 may, in some embodiments, be separated into individual glass sheets 62 by a glass separation apparatus 100 in an elastic region of the glass ribbon. A robot 64 may then transfer the individual glass sheets 62 to a conveyor system using gripping tool 65, whereupon the individual glass sheets may be further processed.

[0042] FIG. 2 shows a schematic perspective end view of a glass manufacturing apparatus 10 that includes a glass delivery device 42 that includes a delivery orifice (delivery slot 142). Molten glass flows from delivery slot 142 to form glass ribbon 58. Specifically, glass ribbon 58 flows from glass delivery device 42 and between first forming roll 180A and second forming roll 180B that each respectively rotate in the directions indicated by dashed and curved arrows. Glass ribbon 58 can be further drawn by applying tension thereto, such as by gravity, opposing sets of edge rolls 72A and 72B and opposing sets of pulling rolls 82A and 82B, to control the dimensions of the glass ribbon 58 as the glass cools and a viscosity of the glass increases. And while FIG. 2 shows one set of opposing edge rolls and pulling rolls, embodiments disclosed herein can include more than one set of opposing edge rolls and / or more than one set of pulling rolls.

[0043] In certain exemplary embodiments, forming rolls 180A and 180B can be configured in accordance with forming rolls shown and described in W02009 / 070236, the entire disclosure of which is incorporated herein by reference. Forming rolls 180A and 180B can be configured so as to provide a controllable adhesion force between the forming rolls 180A and 180B and the glass ribbon 58. The diameter of forming roll 180A and 180B, while not limited to any particular value, may, for example, range from about 20 millimeters to about 500 millimeters and all ranges and subranges in between. In addition, forming rolls 180A and 180B may be comprised of a refractory material, which, while not limited to any particular refractory material, may comprise a metallic material (e.g., stainless steel) and / or a refractory ceramic material.

[0044] Forming rolls 180A and 180B may also comprise one or more mechanisms for controlling their temperatures, such as a cooling mechanism, wherein a cooling fluid flows through or around forming rolls 180A and 180B. For example, forming rolls 180A and 180Bmay comprise at least one channel (not shown) configured to flow a cooling fluid therethrough. Depending on the configuration of temperature control mechanism, the cooling fluid can comprise a liquid, such as water, or a gas, such as nitrogen or air.

[0045] A closest distance between glass delivery device 42 and forming rolls 180A and 180B, while not limited to any particular value, may, for example, range from about 50 millimeters to about 1,000 millimeters and all ranges and subranges in between.

[0046] FIG. 3 shows a schematic perspective side view of a portion of the glass manufacturing apparatus 10 shown in FIG. 2. As can be seen in FIG. 3, molten glass flows from delivery slot 142 of glass delivery device 42 to form glass ribbon 58, which flows between first forming roll 180A and second forming roll 180B (not shown in FIG. 3). Glass ribbon 58 extends below delivery slot 142 in a widthwise direction (indicated by arrow ‘W’ in FIG. 3). As shown in FIG. 3, glass ribbon 58 extension in the widthwise direction shortens or attenuates below the delivery slot 142 from a first width near delivery slot 142 (shown as ‘Wl’) to a second with a distance below delivery slot (shown as ‘W2’), wherein second width is less than first width (which attenuation is indicated by arrows ‘A’). As further shown in FIG. 3, glass ribbon 58 includes a first edge region ‘El’, a central region ‘C’, and a second edge region ‘E2’ in the widthwise direction.

[0047] FIG. 4 shows a schematic bottom view of an example glass manufacturing apparatus 10 that includes edge rolls 300A-D and movable coplanar plates 200A-B in accordance with embodiments herein. Specifically, edge rolls 300A-D includes first edge rolls 300A and opposing second edge rolls 300B proximate delivery slot 142 near the first edge region ‘El’. Edge rolls 300A-D also includes third edge rolls 300C and opposing fourth edge rolls 300D proximate delivery slot 142 near the second edge region ‘E2’. Movable coplanar plates 200A-B include first movable coplanar plate 200A and opposing second movable coplanar plate 200B proximate delivery slot 142 near the central region ‘C’.

[0048] FIG. 5 shows a schematic perspective end view of the example glass manufacturing apparatus 10 of FIG. 4 that includes edge rolls 300A-D and movable coplanar plates 200A-B in accordance with embodiments herein. As shown in FIGS. 4-5, movable coplanar plates 200A-B are each movable between a first position that is relatively farther from the delivery slot 142 and a second position that is relatively closer to the delivery slot 142. For example, such plates may be slidable between said first and second positions (as indicated by arrow ‘S’ in FIGS. 4-5). Such sliding movement may be enabled by methods known to persons having ordinary skill in the art, such as through use of a servo motor and / or counterweight mechanism, etc.

[0049] In certain exemplary embodiments, movable coplanar plates 200A-B can comprise a material having athermal conductivity of less than or equal to about 2 W / m-K at 25°C, such as less than or equal to about 1 W / m-K at 25°C, and further such as less than or equal to about 0.5 W / m-K at 25°C, and yet further such as less than or equal to about 0.2 W / m-K at 25°C, and still yet further such as less than or equal to about 0.1 W / m-K at 25°C, including from about 0.001 W / m-K at 25°C to about 2 W / m-K at 25°C, such as from about 0.01 W / m-K at 25°C to about 1 W / m-K at 25°C, and further such as from about 0.05 W / m-K at 25°C to about 0.5 W / m-K at 25°C.

[0050] While not limited to any specific material, in certain exemplary embodiments, movable coplanar plates 200A-B may comprise at least one material selected from a refractory thermally insulative ceramic material, such as a refractory thermally insulative ceramic material comprising at least one of alumina or mullite, including but not limited to refractory thermally insulative materials comprising alumina available from Zircar Ceramics.

[0051] In certain exemplary embodiments, movable coplanar plates 200A-B may house or be positioned adjacent to a plurality of parallel conduits (not shown) configured to flow a fluid, such as air, therethrough, wherein the fluid is flowed toward delivery slot 142. Movable coplanar plates 200A-B may also house or be positioned adjacent to a fluid containing enclosure or channel, such as a water containing enclosure or channel (not shown). Parallel conduits and / or fluid containing enclosure or channel may be independently movable relative to each other and / or relative to movable coplanar plates 200A-B and can further effectuate heat transfer in the vicinity of delivery slot 142 (e.g., to further effectuate thickness control of glass ribbon 58, etc.). And while FIG. 5 shows coplanar plates 200A-B positioned at a higher elevation than edge rolls 300A-D, embodiments disclosed herein include those in which coplanar plates 200A-B are positioned at the same or lower elevation as edge rolls 300A-D.

[0052] In certain exemplary embodiments, movable coplanar plates 200A-B may comprise or be coated with a refractory thermally conductive material such as silicon carbide (SiC). For example, in certain exemplary embodiments, movable coplanar plates 200A-B may comprise a base portion or layer of thermally insulative material (e.g., comprising at least one of alumina or mullite) that is covered by a layer of thermally conductive material (e.g., SiC). In certain exemplary embodiments, movable coplanar plates 200A-B may comprise a low emissivity surface layer to minimize radiation heat transfer between delivery slot 142 and / or glass ribbon 58 and movable coplanar plates 200A-B. Exemplary low emissivity surface layer materials include, but are not limited to, polished metals, such as polished platinum.

[0053] As shown in FIG. 5, edge rolls 300A and 300B are situated below delivery slot 142 such that they contact glass ribbon 58 at a vertical distance below delivery slot, which is approximately the same as the vertical distance between the delivery slot 142 and the axis of rotation of edge rolls 300A and 300B (shown as ‘VD’ in FIG. 5). In exemplary embodiments, edge rolls 300A and 300B contact the glass ribbon 58 at a vertical distance of less than about 25 millimeters, such as less than about 20 millimeters, and further such as less than about 15 millimeters, including from about 5 millimeters to about 25 millimeters, and further including from about 10 millimeters to about 20 millimeters from the delivery slot 142. In exemplary embodiments, each of the pair of edge rolls 300A and 300B has a diameter (shown as ‘RD’ in FIG. 5) ranging from about 5 millimeters to about 30 millimeters, such as from about 10 millimeters to about 25 millimeters, and further such as from about 15 millimeters to about 20 millimeters. In exemplary embodiments, edge rolls 300A and 300B may comprise a refractory metallic and / or ceramic material.

[0054] FIG. 6 shows a schematic perspective side view of the example glass manufacturing apparatus 10 of FIGS. 4 and 5. As shown in FIG. 6, edge rolls 300B and 300D contact glass ribbon 58 below delivery slot 142. Specifically, edge roll 300B contacts first edge region ‘El’ of glass ribbon 58 and edge roll 300D contacts second edge region ‘E2’ of glass ribbon 58, wherein a central region ‘C’ of the glass ribbon 58 extends between the first edge region ‘El’ and the second edge region ‘E2’ in the widthwise direction of the glass ribbon 58.

[0055] In FIG. 6, a minimum temperature of first edge region ‘El’ contacted by edge roll 300B is shown as Tmini. a minimum temperature of second edge region ‘E2’ contacted by edge roll 300D is shown as Tmin2, and a maximum temperature of central region ‘C’ is shown as Tmax. In addition, a maximum viscosity of first edge region ‘El’ contacted by edge roll 300B is shown as Vmaxi, a maximum viscosity of second edge region ‘E2’ contacted by edge roll 300D is shown as Vmax2, and a minimum viscosity of central region ‘C’ is shown as Vmin. The lowest temperature between Tmin2 is designated as (minimum temperatureof the first edge region ‘El ’ and the second edge region ‘E2’) and the highest viscosity between Vmaxi and Vmax2 is designated as Vmax. (maximum viscosity of the first edge region ‘El’ and the second edge region ‘E2’).

[0056] In certain exemplary embodiments, the first edge region ‘El’ and the second edge region ‘E2’ contacted by the edge rolls 300B or 300D has a viscosity ranging from about 250 kilopoise (kP) to about 1 megapoise (MP), such as from about 300 kilopoiose (kP) to about 600 kilopoise (kP), and further such as from about 350 kilopoise (kP) to about 500 kilopoise(kP). In certain exemplary embodiments, a difference between a minimum temperature, Tmin, of the first edge region ‘El’ and the second edge region ‘E2’ contacted by the edge rolls 300B or 300D and a maximum temperature, Tmax, of the central region ‘C’ between the first edge region ‘El’ and the second edge region ‘E2’ contacted by the edge rolls 300B or 300D is less than about 30°C, such as less than about 25°C, and further such as less than about 20°C, such as from about 5°C to about 30°C, and further such as from about 15°C to about 25 °C. In certain exemplary embodiments, a difference between a maximum viscosity, Vmax, of the first edge region ‘El’ and the second edge region ‘E2’ contacted by the edge rolls 300B or 300D and a minimum viscosity, Vmin, of the central region ‘C’ between the first edge region ‘El’ and the second edge region ‘E2’ contacted by the edge rolls 300B or 300D is less than about 500 kilopoise (kP), such as less than about 250 kilopoise (kP), including from about 50 kilopoise (kP) to about 500 kilopoise (kP), and further such s from about 100 kilopoise (kP) to about 250 kilopoise (kP).

[0057] In the above exemplary embodiments, glass ribbon 58 a predetermined distance below delivery slot 142 has at least a minimum width relative to that of delivery slot. For example, with reference to FIG. 3, glass ribbon may have a first width ‘WT near delivery slot 142 that is approximately equal to that of delivery slot 142 and a second width ‘W2’ a predetermined distance below delivery slot 142 that is less than that of delivery slot 142. For example, embodiments disclosed herein include those in which a width of glass ribbon 58 that is 100 millimeters below delivery slot 142 is at least about 85%, such as at least about 90%, and further such as at least about 95%, including from about 85% to about 95% of the width of delivery slot 142.

[0058] Embodiments disclosed herein include those in which the width of glass ribbon 58 a predetermined distance below delivery slot 142 is relatively insensitive to glass ribbon 58 flow density. Such embodiments include those in which a width of glass ribbon 58 that is 100 millimeters below delivery slot 142 changes by less than about 2%, such as less than about 1.5%, and further such as less than about 1%, including from about 0.5% to about 2%, and further including from about 1% to about 1.5% when a flow density of the glass ribbon of changes by 10%.

[0059] FIG. 7 shows a bottom cutaway view of an example glass ribbon 58 in accordance with embodiments disclosed herein. Glass ribbon 58 includes first edge region ‘El’, central region ‘C’, and second edge region ‘E2’ in the widthwise direction. First edge region ‘El’ has a maximum thickness (shown in FIG. 7 as ‘TE1’), second edge region has a maximum thickness (shown in FIG. 7 as ‘TE2’), and central region has a minimum thickness (shown inFIG. 7 as ‘TC’). In certain exemplary embodiments, central region ‘C’ has a minimum thickness ‘TC’ of less than or equal to about 100 microns, such as less than or equal to about 75 microns, and further such as less than or equal to about 50 microns, such as from about 20 microns to about 100 microns, and further such as from about 25 microns to about 75 microns, and yet further such as from about 30 microns to about 50 microns. In certain exemplary embodiments, a maximum thickness ‘TEI’ of first edge region ‘El’ and a maximum thickness ‘TE2’ of second edge region ‘E2’ is less than about 5 times, such as less than about 4 times, and further such as less than about 3 times, such as from about 1.5 times to about 5 times, and further such as from about 2 times to 4 times, and yet further such as from about 2.5 times to 3 times the minimum thickness ‘TC’ of central region ‘C.’ Embodiments disclosed herein include those in which a boundary between central region ‘C’ and each of first edge region ‘El’ and second edge region ‘E2’ is defined as occurring when glass ribbon 58 thickness from the central region to each edge region first reaches at least 1.12 times the minimum thickness ‘TC’ of central region ‘C.’

[0060] FIG. 8 shows a side cutaway view of an example edge roll 300 in accordance with embodiments disclosed herein. Edge roll 300 is positioned on shaft 302 and comprises central inner channel 304 and annular inner channel 306 circumferentially surrounding central inner channel 304. Central inner channel 304 is configured to flow a working fluid into edge roll 300 (as shown by arrow ‘FI’ in FIG. 8) and annular inner channel 306 is configured to flow the working fluid out of edge roll 300 (as shown by arrows ‘FO’ in FIG. 8).

[0061] Embodiments disclosed herein include those in which the working fluid comprises a liquid, such as water, and / or a gas, such as air, nitrogen, or a noble gas (e.g., helium, neon, argon, etc.). In certain exemplary embodiments the working fluid flowed into edge roll 300 can include both a liquid and a gas, such as a spray or mist of a liquid, such as water, flowed within a stream of gas, such as air. As the liquid and gas stream is flowed through edge roll 300, some or all of the liquid may evaporate, thereby generating an evaporative cooling effect within edge roll 300.

[0062] While not limited to any specific temperature range, in certain exemplary embodiments, the working fluid can have a temperature ranging from about 0°C to about 100°C, such as from about 10°C to about 90°C, and further such as from about 20°C to about 80°C. The flowrate and temperature of the working fluid can be adjusted or varied in accordance with methods known to persons having ordinary skill in the art so as to effectuate the desired degree of heat transfer between the edge roll 300 and the glass ribbon 58.

[0063] In certain exemplary embodiments, glass ribbon 58 can comprise a glass composition comprising a liquidus viscosity of less than or equal to about 100 kilopoise (kP), such as a liquidus viscosity ranging from about 100 poise (P) to about 100 kilopoise (kP), and further such as a liquidus viscosity ranging from about 500 poise (P) to about 50 kilopoise (kP), and yet further such as a liquidus viscosity ranging from about 1 kilopoise (kP) to about 20 kilopoise (kP) and all ranges and subranges in between.

[0064] In certain exemplary embodiments, glass ribbon can comprise a glass composition comprising a liquidus temperature of greater than or equal to about 900°C, such as a liquidus temperature ranging from about 900°C to about l,450°C, and further such as a liquidus temperature ranging from about 950°C to about l,400°C, and yet further such as a liquidus temperature ranging from about l,000°C to about l,350°C.

[0065] Embodiments disclosed herein can enable the production of glass articles, such as thin glass sheets for use in electronic devices, using a variety of glass compositions, including but not limited to glass compositions comprising 58-65 weight percent (wt%) SiCh, 14- 20wt% AI2O3, 8-12wt% B2O3, l-3wt% MgO, 5-10wt% CaO, and 0.5-2wt% SrO, alkali free glass compositions comprising 58-65wt% SiCh, 16-22wt% AI2O3, l-5wt% B2O3, l-4wt% MgO, 2-6wt% CaO, l-4wt% SrO, and 5-10wt% BaO, alkali free glass compositions comprising 57-61wt% SiO2, 17-21wt% AI2O3, 5-8wt% B2O3, l-5wt% MgO, 3-9wt% CaO, 0- 6wt% SrO, and 0-7wt% BaO, or alkali containing glass compositions comprising 55-72wt% SiO2, 12-24wt% AI2O3, 10-18wt% Na2O, 0-10wt% B2O3, 0-5wt% K2O, 0-5wt% MgO, and 0- 5wt% CaO, which, in certain embodiments, may also comprise l-5wt% K2O and l-5wt% MgO.

[0066] Embodiments disclosed herein can also enable increased flexibility in using the same production equipment for different glass compositions, such as glass compositions with differing liquidus temperatures or liquidus viscosities, and / or different glass ribbon flow densities to produce ultra-thin, flat glass sheets, wherein the glass sheets are produced with reduced glass ribbon attenuation (i.e., more usable glass ribbon width) and / or minimized undesirable glass ribbon stress (which stress can, for example, result in process upsets and / or undesirable glass ribbon shapes for producing such sheets) using glass ribbon pulling forces within a workable range.

[0067] For example, embodiments disclosed herein include those in which a glass ribbon comprising a first edge region, a central region, and a second edge region in the widthwise direction is contacted with a pair of edge rolls at each of its edge regions, wherein the first edge region and the second edge region contacted by the edge rolls has a viscosity rangingfrom about 250 kilopoise (kP) to about 1 megapoise (MP), a difference between a minimum temperature, Tmin, of the first edge region and the second edge region contacted by the edge rolls and a maximum temperature, Tmax, of the central region between the first edge region and the second edge region contacted by the edge rolls is less than about 30°C, a difference between a maximum viscosity, Vmax, of the first edge region and the second edge region contacted by the edge rolls and a minimum viscosity, Vmin, of the central region between the first edge region and the second edge region contacted by the edge rolls is less than about 500 kilopoise (kP), the glass ribbon comprises a glass composition comprising a liquidus temperature of greater than or equal to about 900°C, a width of the glass ribbon 100 millimeters below a glass delivery device is at least about 85% of a width of the glass delivery device, the central region of the glass ribbon has a minimum thickness of less than or equal to about 100 microns, a maximum thickness of the first edge region and the second edge region is less than about 5 times a minimum thickness of the central region, and / or a width of the glass ribbon 100 millimeters below the glass delivery device changes by less than about 2% when a flow density of the glass ribbon of changes by 10%.

[0068] While the above embodiments have been described with reference to a slot draw process, it is to be understood that such embodiments are also applicable to other glass forming processes, such as fusion processes, float processes, up-draw processes, tube drawing processes, and press-rolling processes.

[0069] For example, while FIGS. 1-6 show a glass delivery device 42 with a delivery slot 142, embodiments disclosed herein also apply to glass delivery devices that include a glass forming device comprising two sides over which molten glass flows and converges in a root from which molten glass flows to form a glass ribbon, as shown and described, for example in U.S. patent nos. 3,338,696 and 3,682,609, the entire disclosures of which are incorporated herein by reference.

[0070] For example, FIG. 9 shows a schematic perspective end view of an example glass manufacturing apparatus 10’ that includes a glass forming device 42’ comprising two sides over which molten glass flows and converges in a root 142’ from which molten glass flows to form a glass ribbon 58. Glass manufacturing apparatus 10’ includes edge rolls 300A-D and movable coplanar plates 200A-B in accordance with embodiments herein. Movable coplanar plates 200A-B are each movable between a first position that is relatively farther from the root 142’ and a second position that is relatively closer to the root 142’. For example, such plates may be slidable between said first and second positions (as indicated by arrow ‘S’ in FIGS. 4-5). Such sliding movement may be enabled by methods known to persons havingordinary skill in the art, such as through use of a servo motor and / or counterweight mechanism, etc.

[0071] As can be seen in FIG. 9, movable coplanar plates 200A-B are situated at a higher elevation than root 142’ of glass forming device 42’ while edge rolls 300A-D are situated at a lower elevation than root 142’ of glass forming device 42’. Specifically, edge rolls 300A and 300B are situated below root 142’ such that they contact glass ribbon 58 at a vertical distance below root 142’, which is approximately the same as the vertical distance between root 142’ and the axis of rotation of edge rolls 300A and 300B (shown as ‘VD’ in FIG. 9). In exemplary embodiments, edge rolls 300A and 300B contact the glass ribbon 58 at a vertical distance of less than about 25 millimeters, such as less than about 20 millimeters, and further such as less than about 15 millimeters, including from about 5 millimeters to about 25 millimeters, and further including from about 10 millimeters to about 20 millimeters from the root 142’. In exemplary embodiments, each of the pair of edge rolls 300A and 300B has a diameter (shown as ‘RD’ in FIG. 9) ranging from about 5 millimeters to about 30 millimeters, such as from about 10 millimeters to about 25 millimeters, and further such as from about 15 millimeters to about 20 millimeters.

[0072] FIG. 10 shows a schematic perspective end view of an example glass manufacturing apparatus 10’ that includes a glass forming device 42’ comprising two sides over which molten glass flows and converges in a root 142’ from which molten glass flows to form a glass ribbon 58. Glass manufacturing apparatus 10’ includes edge rolls (not shown in FIG. 10) and movable coplanar plates 200A-B. Movable coplanar plates 200A-B each comprise a base portion 202A-B of thermally insulative material (e.g., comprising at least one of alumina or mullite) that is partially covered by a layer of thermally conductive material 204A-B (e.g., SiC), wherein layer of thermally conductive material 204A-B extends between glass forming device 42’ and base portion 202A-B.

[0073] Glass manufacturing apparatus 10’ also includes first movable coplanar housings 400A-B situated below movable coplanar plates 200A-B and second movable coplanar housings 500A-B situated below first movable coplanar housings 400A-B. First movable coplanar housings 400A-B house a plurality of parallel conduits 402A-B configured to flow a fluid, such as air, therethrough, wherein the fluid is flowed toward root 142’. Second movable coplanar housings 500A-B house a fluid (e.g., water) containing channel 502A-B. First movable coplanar housings 400A-B and second movable coplanar housings 500A-B can be independently moveable relative to each other and / or movable coplanar plates 200A-B andand can further effectuate heat transfer in the vicinity of root 142’ (e.g., to further effectuate thickness control of glass ribbon 58, etc.).

[0074] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiment of the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A method of manufacturing a glass article comprising: forming a glass ribbon from a glass delivery device, the glass ribbon extending in a widthwise direction below the glass delivery device, the glass ribbon comprising a first edge region, a central region, and a second edge region in the widthwise direction; and contacting each of the first edge region and the second edge region of the glass ribbon with a pair of edge rolls proximate the glass delivery device.

2. The method of claim 1, wherein the edge rolls contact the glass ribbon at a vertical distance of less than about 25 millimeters from the glass delivery device.

3. The method of claims 1 or 2, wherein the first edge region and the second edge region contacted by the edge rolls has a viscosity ranging from about 250 kilopoise (kP) to about 1 megapoise (MP).

4. The method of any one of claims 1 to 3, wherein a difference between a minimum temperature, Tmin, of the first edge region and the second edge region contacted by the edge rolls and a maximum temperature, Tmax, of the central region between the first edge region and the second edge region contacted by the edge rolls is less than about 30°C.

5. The method of any one of claims 1 to 4, wherein a difference between a maximum viscosity, Vmax, of the first edge region and the second edge region contacted by the edge rolls and a minimum viscosity, Vmin, of the central region between the first edge region and the second edge region contacted by the edge rolls is less than about 500 kilopoise (kP).

6. The method of any one of claims 1 to 5, wherein the glass ribbon comprises a glass composition comprising a liquidus temperature of greater than or equal to about 900°C.

7. The method of any one of claims 1 to 6, wherein a width of the glass ribbon100 millimeters below the glass delivery device is at least about 85% of a width of the glass delivery device.

8. The method of any one of claims 1 to 7, wherein the central region has a minimum thickness of less than or equal to about 100 microns.

9. The method of any one of claims 1 to 8, wherein a maximum thickness of the first edge region and the second edge region is less than about 5 times a minimum thickness of the central region.

10. The method of any one of claims 1 to 9, wherein a width of the glass ribbon100 millimeters below the glass delivery device changes by less than about 2% when a flow density of the glass ribbon of changes by 10%.

11. The method of any one of claims 1 to 10, wherein each of the pair of edge rolls has a diameter ranging from about 5 millimeters to about 30 millimeters.

12. The method of any one of claims 1 to 11, wherein a working fluid is flowed through each of the pair of edge rolls.

13. A glass article manufacturing apparatus comprising: a glass delivery device extending in a widthwise direction and comprising a first edge region, a central region, and a second edge region; a pair of edge rolls proximate the glass delivery device; and a pair of opposing movable coplanar plates proximate the pair of edge rolls.

14. The apparatus of claim 13, wherein the edge rolls are configured to rotate about a central axis situated at a vertical distance of less than about 25 millimeters from the glass delivery device.

15. The apparatus of claims 13 or 14, wherein each of the pair of edge rolls has a diameter ranging from about 5 millimeters to about 30 millimeters.

16. The apparatus of any one of claims 13 to 15, wherein each of the pair of edge rolls is configured to flow a working fluid therethrough.

17. The apparatus of any one of claims 13 to 16, wherein each of the pair of edge rolls comprises at least one of a refractory metallic or ceramic material.

18. The apparatus of any one of claims 13 to 17, wherein the apparatus comprises at least one of: a pair of first movable coplanar housings, each of the first movable coplanar housings comprising a plurality of parallel conduits configured to flow a flow therethrough; and a pair of second movable coplanar housings, each of the second movable coplanar housings comprising a fluid containing channel, wherein each of the first movable coplanar housings, the second movable coplanar housings, and / or the opposing movable coplanar plates are each independently movable relative to each other.

19. A glass article made by the method of any one of claims 1 to 12.

20. An electronic device comprising the glass article of claim 19.

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