Method for achieving a stress profile in a glass
AssigneeCorning Incorporated
InventorsDouglas Clippinger Allan, Xiaoju Guo, Guangli Hu, Gaozhu Peng
Life of this patent
Estimating the term…
Abstract
A method for generating various stress profiles for chemically strengthened glass. An alkali aluminosilicate glass is brought into contact with an ion exchange media such as, for example, a molten salt bath containing an alkali metal cation that is larger than an alkali metal cation in the glass. The ion exchange is carried out at temperatures greater than about 420° C. and at least about 30° C. below the anneal point of the glass.
Claims29
A method of strengthening an alkali aluminosilicate glass comprising first metal cations and having an anneal point, the method comprising:
- a. immersing the alkali aluminosilicate glass in a molten salt bath, the molten salt bath comprising at least one salt of a second metal, wherein cations of the second metal are larger than the first metal cations;
- b. ion exchanging the cations of the second metal from the molten salt bath for the first metal cations in the alkali aluminosilicate glass at a temperature of greater than about 420° C. and at least about 30° C. less than the anneal point, wherein ion exchanging forms a region of compressive stress, the region extending from a surface of the glass to a depth of layer of at least 40 μm into the glass, and wherein a compressive stress at a first depth is at least about 50% of a compressive stress at the surface, the first depth being between about 30% and about 70% of the depth of layer.
An alkali aluminosilicate glass article, the alkali aluminosilicate glass article having a region under a compressive stress, the region extending from a surface of the alkali aluminosilicate glass article to a depth of layer of at least about 40 μm within the alkali aluminosilicate glass article, wherein the alkali aluminosilicate glass article has a compressive stress at the surface and a first compressive stress at a first depth, the first depth being between about 30% and about 70% of the depth of layer, wherein the first compressive stress is at least about 50% of the compressive stress at the surface.
Dependencies are inferred from the claim text.