| 摘要 |
PROBLEM TO BE SOLVED: To provide a safe strengthened glass plate of high strength that does not produce sharp fragments when crushed. ! SOLUTION: A manufacturing method of a strengthened glass plate includes a step for forming a pattern of a low alkali concentration region where the content of an alkali metal ion is low, and a chemically strengthening step for chemically strengthening a glass substrate having the pattern of a low alkali concentration region. In the step for forming a pattern of a low alkali concentration region, the glass substrate containing an alkali metal oxide is arranged between a cathode and an anode and a direct voltage is applied to between the cathode and the anode to generate corona discharge. At least one kind of alkali metal ion is thus moved to the anode side of the glass substrate in a predetermined region of a surface layer part on the cathode side. ! COPYRIGHT: (C)2015,JPO&INPIT |
