| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass substrate on which a sulfate protective film, that has high acid resistance and high strength and is cleaned and removed more easily, can be formed.SOLUTION: The glass substrate: has a first surface; contains silicon, an alkali metal, an alkaline-earth metal, and oxygen; has 640°C or higher glass transition temperature; has 3.0 or larger Y/X when the first hydrogen ion concentration at the depth of 500-5,000 nm from the first surface is defined as X [ppm] and the second hydrogen ion concentration at the depth of 40-60 nm from the first surface is defined as Y [ppm]; exhibits 0.5 mg/cmor smaller elution quantity when such an acid resistance test is conducted that the glass substrate is immersed in diluted hydrochloric acid, which is kept at 90°C and has 1 mole/liter concentration, for 20 hours; and has 500 or higher Vickers hardness Hv.SELECTED DRAWING: None |
