| 摘要 |
PROBLEM TO BE SOLVED: To provide a tempered glass or the like which can be obtained through a short-time ion exchange treatment without requiring polishing. SOLUTION: The tempered glass is characterized by being composed of glass containing, by mass, 60-80% of SiO<SB>2</SB>, 3-18% of Al<SB>2</SB>O<SB>3</SB>, 0-7% of B<SB>2</SB>O<SB>3</SB>, 0.01-10% of Li<SB>2</SB>O, 4-16% of Na<SB>2</SB>O, 0-15% of K<SB>2</SB>O and 0-5% of R'O (R'O represents the total amount of alkaline earth metal oxides), while having a molar ratio (Li<SB>2</SB>O + Al<SB>2</SB>O<SB>3</SB>)/(Na<SB>2</SB>O + K<SB>2</SB>O) within a 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. COPYRIGHT: (C)2008,JPO&INPIT |
