A laminated glass article has a first layer having a first ion exchange diffusivity, D.sub.0, and a second layer adjacent to the first layer and having a second ion exchange diffusivity, D.sub.1. D.sub.0/D.sub.1 is from about 1.2 to about 10, or D.sub.0/D.sub.1 is from about 0.05 to about 0.95. A method for manufacturing the laminated glass article includes forming a first layer having a first ion exchange diffusivity, D.sub.0, and forming a second layer adjacent to the first layer and having a second ion exchange diffusivity, D.sub.1. The laminated glass article can be strengthened by an ion exchange process to form a strengthened laminated glass article having a compressive stress layer with a depth of layer from about 8 μm to about 100 μm.

An apparatus for forming glass tubing is described. The apparatus for forming glass tubing comprises an endless former with an outer surface and an inner passage defining an inner surface. The apparatus for forming glass tubing further comprises two chambers from which molten glass may flow. One chamber flows molten glass to the outer surface of the endless former and another chamber flows molten glass to the inner surface of the endless former. The two flows of molten glass meet at the bottom of the former to form glass tubing.

An apparatus for forming glass tubing is described. The apparatus for forming glass tubing comprises an endless former with an outer surface and an inner passage defining an inner surface. The apparatus for forming glass tubing further comprises two chambers from which molten glass may flow. One chamber flows molten glass to the outer surface of the endless former and another chamber flows molten glass to the inner surface of the endless former. The two flows of molten glass meet at the bottom of the former to form glass tubing.

The present invention is directed to methods for making high quality glass tubes, and apparatuses for making high quality glass tubes. Because glass tubes made using the methods and apparatuses disclosed herein are substantially free from the optical defect known as paneling, the glass tubes may be used in displays for consumer electronic devices. The glass tubes are made by a continuous process in which a flow of molten glass is provided on an inner surface of a hollow, rotating mandrel such that the glass coats the inner surface of the mandrel and flows downstream on the inner surface of the mandrel, during which it is cooled to provide a higher viscosity. The glass is then removed from the mandrel and drawn to obtain a glass tube. A flow of molten glass may also be provided on the outer surface of the mandrel and joined with the glass flow on the inner surface of the mandrel when the glass flows exit the mandrel. The apparatuses presented herein are configured to provide high quality glass tubes using this method.

A method for strengthening an edge of a glass laminate including a glass core layer positioned between a first glass clad layer and a second glass clad layer may include forming a channel in the edge of the glass laminate. Sidewalls of the channel may be formed from the first glass clad layer and the second glass clad layer. Glass filler material having a filler coefficient of thermal expansion greater than a core coefficient of thermal expansion may be positioned in the channel. The glass filler material and the sidewalls of the channel may be fused to the second glass clad layer thereby forming an edge cap over the channel. The edge of the glass laminate is under compressive stress after the glass filler material is enclosed in the channel.

Intermediate to high CTE glass compositions and laminates formed from the same are described. The glasses described herein have properties, such as liquidus viscosity or liquidus temperature, which make them particularly well suited for use in fusion forming processes, such as the fusion down draw process and/or the fusion lamination process. Further, the glass composition may be used in a laminated glass article, such as a laminated glass article formed by a fusion laminate process, to provide strengthened laminates via clad compression as a result of CTE mismatch between the core glass and clad glass.

Intermediate to high CTE glass compositions and laminates formed from the same are described. The glasses described herein have properties, such as liquidus viscosity or liquidus temperature, which make them particularly well suited for use in fusion forming processes, such as the fusion down draw process and/or the fusion lamination process. Further, the glass composition may be used in a laminated glass article, such as a laminated glass article formed by a fusion laminate process, to provide strengthened laminates via clad compression as a result of CTE mismatch between the core glass and clad glass.

A method for forming a laminated glass article may include flowing a molten first glass composition having a first R.sub.2O concentration and a first fining agent with a first fining agent concentration. The method may also include flowing a molten second glass composition having a second R.sub.2O concentration less than the first R.sub.2O concentration of the first glass composition and a second fining agent with a second fining agent concentration that is greater than or equal to the first fining agent concentration of the first glass composition. The molten first glass composition may be contacted with the molten second glass composition to form an interface between the molten first glass composition and the molten second glass composition.

A method for forming a laminated glass article may include flowing a molten first glass composition having a first R.sub.2O concentration and a first fining agent with a first fining agent concentration. The method may also include flowing a molten second glass composition having a second R.sub.2O concentration less than the first R.sub.2O concentration of the first glass composition and a second fining agent with a second fining agent concentration that is greater than or equal to the first fining agent concentration of the first glass composition. The molten first glass composition may be contacted with the molten second glass composition to form an interface between the molten first glass composition and the molten second glass composition.

A base substrate includes a first base layer and an electrostatic resistant layer that are disposed in a stack.