| 摘要 |
<p>Disclosed is a tempered glass or the like which can be obtained through a short-time ion exchange treatment without requiring polishing. Specifically disclosed is a tempered glass characterized by being composed of a glass containing, in mass%, 60-80% of SiO<SUB>2</SUB>, 3-18% of Al<SUB>2</SUB>O<SUB>3</SUB>, 0-7% of B<SUB>2</SUB>O<SUB>3</SUB>, 0.01-10% of Li<SUB>2</SUB>O, 4-16% of Na<SUB>2</SUB>O, 0-15% of K<SUB>2</SUB>O and 0-5% of R'O (the amount of alkaline earth metal oxides in total), while having a molar ratio (Li<SUB>2</SUB>O + Al<SUB>2</SUB>O<SUB>3</SUB>)/(Na<SUB>2</SUB>O + K<SUB>2</SUB>O) within the range of 0.1-2. This tempered glass is also characterized by having a compression stress layer in the surface. This tempered glass can be obtained through the following procedure: a glass material prepared to have a certain glass composition is melted and then formed into a plate by an overflow downdraw glass forming method, and after that a compression stress layer is formed in the surface of the glass plate through an ion exchange treatment.</p> |
