Cover glass and method for producing same

Abstract

A cover glass having a compressive-stress layer on the principal surfaces thereof, and having a glass composition containing 50% to 70% by mole of SiO2, 3% to 20% by mole of Al2O3, 5% to 25% by mole of Na2O, more than 0% by mole and less than or equal to 2.5% by mole of Li2O, 0% to 5.5% by mole of K2O, and 0% to less than 3% by mole of B2O3. Also disclosed is a method for producing a cover glass which includes: (i) preparing molten glass by melting a glass raw material; (ii) forming the prepared molten glass into a plate-like shape by a down-draw process and thereby obtaining a glass substrate; and (iii) forming a compressive-stress layer on the surface of the glass substrate.

Description

technical field [0001] The invention relates to a cover glass and its manufacturing method. Background technique [0002] Conventionally, sheet glass has been used as a cover glass for protecting liquid crystal screens such as mobile phones, PDAs, digital cameras, and FPDs, or as a cover glass for housings of portable terminal devices. In recent years, these mobile phones, PDAs, and the like tend to be thinner and more functional, and require high mechanical strength. Therefore, tempered glass chemically strengthened for the strength of the thin glass substrate is used as a cover glass. [0003] Such tempered glass is chemically strengthened, for example, by ion exchange treatment. Ion exchange treatment is usually the following method: immerse the glass in a molten salt containing potassium and / or sodium at a temperature of about 350-550°C, so that the sodium ions and lithium ions on the glass surface and the potassium in the ion-exchange salt Ion or sodium ion exchange ...

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In addition, new problems arise, such as complicated steps before the measurement.

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