| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that when a small area of about 2 mm×2 mm square or less of a glass plate is tempered, it is difficult to temper the area of the glass plate by an air cooling tempering method because the tempered part is too large, and it is impossible to appropriately temper the area of the glass plate by a foreign phase forming process using a laser of an ultra-short wavelength because the tempered part is adversely too small. SOLUTION: A tempered glass plate has a thickness of 0.1-5 mm, and in the tempered glass plate, a boundary generated by laser irradiation has a retardation of≥25 nm, wherein the retardation is measured by incident light having a wavelength of 546 nm, observed in a top view, and the diameter of the inscribed circle of the boundary is≥20μm and≤1 mm, and the area up to 2.5 times of the radius of the inscribed circle from the outside of the boundary is tempered. COPYRIGHT: (C)2008,JPO&INPIT
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