Abstract: Disclosed are synthetic silica glass body with a birefringence pattern having low fast axis direction randomness factor and glass reflow process. The glass reflow process comprises steps of: providing a glass tube having a notch; and thermally reflowing the glass tube to form a glass plate. The process can be advantageously used to produce fused silica glass plate without observable striae when viewed in the direction of optical axis. Also disclosed are optical members comprising the fused silica glass body and a process for reflowing glass cylinders.

Abstract: Methods for controlling thickness variations across the width of a glass ribbon (104) are provided. The methods employ a set of thermal elements (106) for locally controlling the temperature of the ribbon (104). The operating values for the thermal elements (106) are selected using an iterative procedure in which thickness variations measured during a given iteration are employed in a mathematical procedure which selects the operating values for the next iteration. In practice, the method can bring thickness variations of glass sheets within commercial specifications in just a few iterations, e.g., 2-4 iterations.

Abstract: A flange (13) for use in direct resistance heating of a glass-carrying vessel (10), such as a finer, is provided. The flange comprises a plurality of electrically-conductive rings which include an innermost ring (140) which is joined to the vessel's exterior wall (12) during use of the flange and an outermost ring (150) which receives electrical current during use of the flange. The innermost ring (140) comprises a high-temperature metal which comprises at least 80% platinum and the outermost ring (150) comprises at least 99.0% nickel. This combination of materials both increases the reliability of the flange and reduces its cost. In certain embodiments, the flange can also include one or more rings (190) composed of a platinum-nickel alloy which has a lower thermal conductivity than platinum or nickel and thus can serve to reduce heat loss through the flange.

Abstract: Methods for controlling thickness variations across the width of a glass ribbon (104) are provided. The methods employ a set of thermal elements (106) for locally controlling the temperature of the ribbon (104). The operating values for the thermal elements (106) are selected using an iterative procedure in which thickness variations measured during a given iteration are employed in a mathematical procedure which selects the operating values for the next iteration. In practice, the method can bring thickness variations of glass sheets within commercial specifications in just a few iterations, e.g., 2-4 iterations.

Abstract: A method of making a fused silica plate includes providing a fused silica blank having a length, a longitudinal axis, and an outer diameter. The method further includes forming a slot in the fused silica blank which extends from the outer diameter to a location at or offset from a center of the fused silica blank and is substantially parallel to the longitudinal axis of the fused silica blank. The slot is defined by a concave surface located at or offset from the center of the fused silica blank, a first side surface extending between a first edge of the concave surface and the outer diameter of the fused silica blank, and a second side surface extending between a second edge of the concave surface and the outer diameter of the fused silica blank. At least one of the first and second side surfaces are connected to the concave surface by a chamfered surface. The method further includes rolling out the fused silica blank having the slot to form a fused silica plate.

Abstract: Methods and apparatus for controlling the stress in, and the shape of, the glass ribbon (15) formed in a downdraw glass manufacturing process (e.g., the fusion downdraw process) are provided. In certain embodiments, the control is achieved by cooling the bead portions (21a, 21b) of the ribbon (15) at a rate which provides a heat flux Q?b at the thickest part of the bead (23a, 23b) which is given by Q?b=Q?q+?Q?, where (i) Q?q is the heat flux at a transverse position adjacent to the bead portion (21a, 21b) at which the ribbon's thickness equals 1.05*tcenter, where tcenter is the final thickness at the ribbon's center line (17), and (ii) ?Q??(tb/tq?1)Q?q+10 kilowatts/meter2, where tb is the thickness of the thickest part of the bead portion. The cooling can take place along the entire length of the ribbon (15) or at selected locations, e.g.

Abstract: Methods and apparatus for controlling the stress in, and the shape of, the glass ribbon (15) formed in a downdraw glass manufacturing process (e.g., the fusion downdraw process) are provided. In certain embodiments, the control is achieved by cooling the bead portions (21a, 21b) of the ribbon (15) at a rate which provides a heat flux Q?b at the thickest part of the bead (23a, 23b) which is given by Q?b=Q?q+?Q?, where (i) Q?q is the heat flux at a transverse position adjacent to the bead portion (21a, 21b) at which the ribbon's thickness equals 1.05*tcenter, where tcenter is the final thickness at the ribbon's center line (17), and (ii) ?Q??(tb/tq?1)Q?q+10 kilowatts/meter2, where tb is the thickness of the thickest part of the bead portion. The cooling can take place along the entire length of the ribbon (15) or at selected locations, e.g.

Abstract: Methods for controlling thickness variations across the width of a glass ribbon (104) are provided. The methods employ a set of thermal elements (106) for locally controlling the temperature of the ribbon (104). The operating values for the thermal elements (106) are selected using an iterative procedure in which thickness variations measured during a given iteration are employed in a mathematical procedure which selects the operating values for the next iteration. In practice, the method can bring thickness variations of glass sheets within commercial specifications in just a few iterations, e.g., 2-4 iterations.

Abstract: Systems, methods, apparatus and products relate to display glass from curved glass ribbons, to improve shape stability in glass ribbons, to creation of reduced stress glass ribbons, and to creation of improved shape stability and reduced stress of display glass, which may include forming slightly a curved glass ribbon in a fusion draw machine (FDM). One or more embodiments may include an isopipe having a desired curvature; an isopipe having a desired incline; an offset draw device operable to draw the glass ribbon in an inclined ribbon draw direction; one or more air jets or vacuum operable to apply air pressure to a first side of the glass ribbon, thereby creating a pressure differential on the first side; and/or one or more electrostatic force generators operable to apply electrostatic force to a first side of the glass ribbon, thereby generating an electric field differential across the glass ribbon.

Abstract: Methods and apparatus for controlling the stress in, and the shape of, the glass ribbon (15) formed in a downdraw glass manufacturing process (e.g., the fusion downdraw process) are provided. In certain embodiments, the control is achieved by cooling the bead portions (21a, 21b) of the ribbon (15) at a rate which provides a heat flux Q?b at the thickest part of the bead (23a, 23b) which is given by Q?b=Q?q+?Q?, where (i) Q?q is the heat flux at a transverse position adjacent to the bead portion (21a, 21b) at which the ribbon's thickness equals 1.05*tcenter, where tcenter is the final thickness at the ribbon's center line (17), and (ii) ?Q??(tb/tq?1)Q?q+10 kilowatts/meter2, where tb is the thickness of the thickest part of the bead portion. The cooling can take place along the entire length of the ribbon (15) or at selected locations, e.g.

Abstract: In the formation of sheet glass by the overflow downdraw process, the width of usable sheet glass is maximized by downwardly flowing edge portions of the sheet over web-like members and thereafter over extensions which intersect with and are downwardly inclined relative to the web-like members to thin edge portions of the glass flow and maintain sheet width. The extension members are preferably removably attached to the web-like members, greatly facilitating replacement of the more easily damaged extension members.

Abstract: A flange (13) for use in direct resistance heating of a glass-carrying vessel (10), such as a finer, is provided. The flange comprises a plurality of electrically-conductive rings which include an innermost ring (140) which is joined to the vessel's exterior wall (12) during use of the flange and an outermost ring (150) which receives electrical current during use of the flange. The innermost ring (140) comprises a high-temperature metal which comprises at least 80% platinum and the outermost ring (150) comprises at least 99.0% nickel. This combination of materials both increases the reliability of the flange and reduces its cost. In certain embodiments, the flange can also include one or more rings (190) composed of a platinum-nickel alloy which has a lower thermal conductivity than platinum or nickel and thus can serve to reduce heat loss through the flange.

Abstract: A method of making a fused silica plate includes providing a fused silica blank having a length, a longitudinal axis, and an outer diameter. The method further includes forming a slot in the fused silica blank which extends from the outer diameter to a location at or offset from a center of the fused silica blank and is substantially parallel to the longitudinal axis of the fused silica blank. The slot is defined by a concave surface located at or offset from the center of the fused silica blank, a first side surface extending between a first edge of the concave surface and the outer diameter of the fused silica blank, and a second side surface extending between a second edge of the concave surface and the outer diameter of the fused silica blank. At least one of the first and second side surfaces are connected to the concave surface by a chamfered surface. The method further includes rolling out the fused silica blank having the slot to form a fused silica plate.

Abstract: Disclosed are synthetic silica glass body with a birefringence pattern having low fast axis direction randomness factor and glass reflow process. The glass reflow process comprises steps of: providing a glass tube having a notch; and thermally reflowing the glass tube to form a glass plate. The process can be advantageously used to produce fused silica glass plate without observable striae when viewed in the direction of optical axis. Also disclosed are optical members comprising the fused silica glass body and a process for reflowing glass cylinders.

Abstract: In the formation of sheet glass by the overflow downdraw process, the width of usable sheet glass is maximized by downwardly flowing edge portions of the sheet over web-like members and thereafter over extensions which intersect with and are downwardly inclined relative to the web-like members to thin edge portions of the glass flow and maintain sheet width. The extension members are preferably removably attached to the web-like members, greatly facilitating replacement of the more easily damaged extension members.

Abstract: In the formation of sheet glass by the overflow downdraw process, the width of usable sheet glass is maximized by downwardly flowing edge portions of the sheet over web-like members and thereafter over extensions which intersect with and are downwardly inclined relative to the web-like members to thin edge portions of the glass flow and maintain sheet width. The extension members are preferably removably attached to the web-like members, greatly facilitating replacement of the more easily damaged extension members.

Abstract: Systems, methods, apparatus and products relate to display glass from curved glass ribbons, to improve shape stability in glass ribbons, to creation of reduced stress glass ribbons, and to creation of improved shape stability and reduced stress of display glass, which may include forming slightly a curved glass ribbon in a fusion draw machine (FDM). One or more embodiments may include an isopipe having a desired curvature; an isopipe having a desired incline; an offset draw device operable to draw the glass ribbon in an inclined ribbon draw direction; one or more air jets or vacuum operable to apply air pressure to a first side of the glass ribbon, thereby creating a pressure differential on the first side; and/or one or more electrostatic force generators operable to apply electrostatic force to a first side of the glass ribbon, thereby generating an electric field differential across the glass ribbon.