In a glass sheet 12 for chemical strengthening having a thickness of 0.1 mm or less, the glass sheet 12 has a warped shape as a whole or includes a warped part in a portion thereof. When the glass sheet 12 is placed on a horizontal surface with one main surface 12a facing upward, a first peak position D1 is present in a part inside a peripheral edge portion 12e of the glass sheet 12, where the first peak position D1 is a position having the highest height from the horizontal surface in the glass sheet 12, and the peripheral edge portion 12e is a part having a width of 10 mm along a peripheral edge of the glass sheet 12.

A glass roll of band-shaped glass film is free of skew and single slack when a roll-to-roll mode is used. The band-shaped glass film is wound into a roll shape and has creases formed thereon. The band-shaped glass film includes an effective section with two side edges in a width direction extending parallel to each other, and leading and trailing end portions extending parallel to the width direction. When a length from the leading end portion to the trailing end portion along a surface of the effective section is measured along each of a first position along one side edge and a second position along another side edge, a difference between the first and second measurement lengths is 400 ppm or less of a longer measurement length of the first and second measurement lengths.

A method of forming a glass sheet comprises: (a) forming a ribbon of glass from molten glass with a pair of forming rollers; (b) reducing horizontal temperature variability of the ribbon of glass to be 10? C. or less across 80 percent of an entire width of the ribbon of glass before the ribbon of glass cools to a glass transition temperature; (c) controlling a cooling rate of the ribbon of glass while the ribbon of glass moves vertically downward within a setting zone such that the ribbon of glass has a first average cooling rate before the ribbon of glass cools to the glass transition temperature and a second average cooling rate after the ribbon of glass cools to the glass transition temperature, the first average cooling rate being less than the second average cooling rate; and (d) separating a glass sheet from the ribbon of glass.

Apparatuses and methods are described for controlling the width and thickness of glass during glass sheet production. The apparatuses and methods employ a gas cooling mechanism that is designed to extract heat from molten glass during the drawdown process to reduce width attenuation and generate more uniform glass. In some examples, a nozzle of a glass forming apparatus includes a first nozzle portion with a first glass forming surface, and a second nozzle portion opposite the first nozzle portion, where the second nozzle portion includes a second glass forming surface opposite the first glass forming surface. The nozzle also includes a first cavity within the first nozzle portion, and a second cavity within the second nozzle portion. Gas, such as air, is delivered to each of the first cavity and the second cavity to cool molten glass as it is drawn between the first and second glass forming surfaces.

Provided is a method comprises: continuously forming an elongated, glass film having marginal portions from molten glass into a given shape having two marginal portions, in width-directional opposite edge regions thereof, wherein the glass film having marginal portions has the marginal portions, and an effective portion formed in a width-directional central region of the glass film having marginal portions; annealing the glass film having marginal portions; continuously forming resin tapes on the glass film having marginal portions at positions adjacent to and away by a given distance from the respective marginal portions, to extend in a length direction of the glass film having marginal portions; and continuously removing each of the marginal portions from the glass film having marginal portions, along a position between the marginal portion and a corresponding one of the resin tapes, or at a given width-directional position within the corresponding resin tape.

A glass manufacturing apparatus includes a forming apparatus forming a glass ribbon. An enclosure is positioned downstream from the forming apparatus and includes a first chamber, a first end defining an inlet opening, and a second end defining an outlet opening. A first enclosure wall of the enclosure includes an enclosure wall opening defining a gas travel path from the first chamber to an exterior of the enclosure. A ribbon travel path extends through the first chamber. A first conduit extends along a first side of the enclosure and includes a second chamber. A gas opening provides fluid communication between the first chamber and the second chamber. A first gas source is in fluid communication with the second chamber. The first gas source delivers a first gas to the first chamber through the second chamber. Methods of manufacturing a glass ribbon are provided.

A method for forming a laminated glass article with a ceramic phase, such as a beta-spodumene phase, located at least at the junctures between a glass core and directly adjacent glass clad layers, and in some embodiments located throughout the laminated glass article. In some embodiments, a method is disclosed herein for forming a beta-spodumene glass-ceramic sheet, or a laminated glass article having a ceramic phase, or a laminated glass article having a beta-spodumene glass-ceramic, is disclosed.

Embodiments of a method of forming a glass article are disclosed. The methods include supplying a glass ribbon in a first direction and redirecting the glass ribbon to a second direction different from the first direction without contacting the glass ribbon with a solid material. The glass ribbon may exhibit a viscosity of less than about 10.sup.8 Poise and a thickness of about 1 mm or less. Embodiments of a glass or glass-ceramic forming apparatus are also disclosed. The apparatus may include a glass feed device for supplying a glass ribbon in a first direction and a redirection system disposed underneath the glass feed device for redirecting the glass ribbon to a second direction. In one or more embodiments, the redirection system comprising at least one gas bearing system for supplying a gas film to support the glass ribbon.

Provided is a method of manufacturing a glass film, including: a forming step of forming a band-shaped glass film (1); a conveyance direction changing step of changing a conveyance direction of the band-shaped glass film (1) from a vertically downward direction to a horizontal direction by conveying the band-shaped glass film (1) along a curved conveyance path (R1); and a horizontal conveyance step of conveying the band-shaped glass film (1) in the horizontal direction along a horizontal conveyance path (R2), wherein, when some sections of the band-shaped glass film (1) are to be discarded, the method involves: a separating step of separating a discard glass part (1x) from the band-shaped glass film (1) on the horizontal conveyance path (R2); and a discarding step of discarding the separated discard glass part (1x) by causing the discard glass part (1x) to leave the horizontal conveyance path (R2) downward.

An alkali-free glass substrate which is a glass substrate includes, as represented by molar percentage based on oxides, 0.1% to 10% of ZnO. The alkali-free glass substrate has an average coefficient of thermal expansion .sub.50/100 at 50 to 100 C. of from 2.70 ppm/ C. to 3.20 ppm/ C., an average coefficient of thermal expansion .sub.200/300 at 200 to 300 C. of from 3.45 ppm/ C. to 3.95 ppm/ C., and a value .sub.200/300/.sub.50/100 obtained by dividing the average coefficient of thermal expansion .sub.200/300 at 200 to 300 C. by the average coefficient of thermal expansion .sub.50/100 at 50 to 100 C. of from 1.20 to 1.30.