| 摘要 |
PROBLEM TO BE SOLVED: To obtain a tempered glass plate of which the fragmentation is accelerated when it is crushed keeping sufficient strength to the glass plate having the thickness of 3 mm or less. SOLUTION: A stress pattern is formed on the tempered glass plate by air- cooling and tempering with a cooling medium blown from a plurality of nozzles set in parallel. The stress pattern is formed by ranging plural cells of which the center is just under each nozzle. The flat face stress is in a compressed state at a central area and the circumferential frame areas of the cells. The flat face stress is in a tensile state at the area between the central area and the circumferential frame area. |
