Provided is a material which is excellent in heat resistance and weather resistance while having low dielectric characteristics and flexibility. A glass film of the present invention is a glass film, which has a film thickness of 100 μm or less, wherein the glass film has a specific dielectric constant at 25° C. and a frequency of 2.45 GHz of 5 or less and a dielectric dissipation factor at 25° C. and a frequency of 2.45 GHz of 0.01 or less.

A laminated glass article comprises a core layer comprising a core glass composition having an average core coefficient of thermal expansion (CTE.sub.core) and a clad layer directly adjacent to the core layer and comprising a clad glass composition having an average clad coefficient of thermal expansion (CTE.sub.clad) that is less than the CTE.sub.core such that the clad layer is in compression and the core layer is in tension. A compressive stress of the clad layer increases with increasing distance from the outer surface of the clad layer, transitions to a minimum tensile stress as a step-change at an interface region between the core layer and the clad layer, and a magnitude of the tensile stress increases continuously to a maximum tensile stress in the core layer. Other stress profiles, and methods of preparing laminated glass articles are also disclosed.

Glass-based articles that include a compressive stress layer extending from a surface of the glass-based article to a depth of compression are formed by exposing glass-based substrates to water vapor containing environments. The glass-based substrates have compositions selected to be fusion formable, to be steam strengthen able, and to avoid the formation of platinum defects during the forming process. The methods of forming the glass-based articles may include elevated pressures and/or multiple exposures to water vapor containing environments.

Methods of manufacturing a ribbon can comprise identifying a location of a nonuniformity in a characteristic of a molten portion of a moving ribbon. The methods can further comprise impinging a deflected pulsed laser beam on a heating zone comprising a location of a nonuniformity in the molten portion of the ribbon. In some embodiments, the heating zone can be elongated in a travel direction of a travel path of the moving ribbon. In some embodiments, the pulsed laser beam can be reflected off a reflective surface of a polygonal reflecting device rotating at a substantially constant angular velocity. In some embodiments, the methods can include impinging the deflected pulsed laser beam on a sensing device to generate a signal. The methods can further comprise calibrating a location of the deflected pulsed laser beam based on the signal from the sensing device.

Provided is a method for producing a glass substrate that can reduce the dimensional change during heat treatment while avoiding shortening of facilities' service lives. A method for producing a glass substrate includes melting and forming a glass raw material to produce a glass substrate having a strain point of 690 to 750° C., wherein an average cooling rate in a temperature range from (an annealing point plus 150° C.) to (the annealing point minus 200° C.) in a cooling process during the forming is adjusted to 100 to 400° C./min to obtain the glass substrate having a degree of thermal contraction of 15 ppm or less when subjected to a heat treatment at 500° C. for an hour.

A glass manufacturing apparatus can include a conduit connected to a delivery vessel and an inlet of a forming vessel. The conduit includes a closed sidewall surrounding a channel extending in a flow direction of the conduit. The closed sidewall is continuous from the delivery vessel to the inlet of the forming vessel to define a closed atmosphere from the delivery vessel, through the conduit, and through the inlet of the forming vessel. The glass manufacturing apparatus can include a heating enclosure including a heating wall and a first heating element. The heating wall surrounds a chamber within which the conduit extends. The first heating element is positioned within the chamber between the heating wall and the conduit to increase a temperature within the channel. Methods for manufacturing a glass ribbon with a glass manufacturing apparatus are provided.

Glass manufacturing methods disclosed herein include delivering a molten glass to a melting vessel, and melting the batch materials to produce a molten glass comprising less than about 20 ppm CrO.sub.3. Glass articles produced by these methods are also disclosed herein.

Various improvements for dual-elevation edge roll system used in fused downdraw glass forming process are disclosed.

The present disclosure provides a device and a method with which flat glasses with particularly uniform thickness can be obtained. The methods are drawing methods in which a glass ribbon is drawn. In the method an aperture is used which allows a defined very small slit between the glass ribbon and the aperture also in the case of a change of the position of the glass ribbon.

A method of manufacturing a glass includes a conveying step of moving a conveyance sheet material that contacts a lower surface of a glass film, to thereby convey the glass film. The conveyance sheet material includes a first contact portion that contacts the lower surface of the glass film on an upstream side in a manufacture-related process step, a second contact portion that contacts the lower surface of the glass film on a downstream side in the manufacture-related process step, and a non-contact portion that is prevented from contacting the lower surface of the glass film. In this method, the manufacture-related process step includes subjecting the glass film to a predetermined process at a position corresponding to the non-contact portion between the first and second contact portions while simultaneously moving the first, second, and non-contact portions of the conveyance sheet material through the conveying step.