| 摘要 |
A tempered glass includes a glass sheet having a thickness of 2.3-3.5 mm, an average surface compressive stress of 1000-1300 kg/cm2, and a plurality of first and second belt-like regions. Each of the second belt-like regions is interposed between adjacent ones of the first belt-like regions. Each of the first belt-like regions has a width of 10-30 mm and a plurality of first reference points, each having a principal stress difference of 120 kg/cm2 or less, which is larger than principal stress differences at areas of each of the first belt-like regions which are peripheral to each of the first reference points. The first principal stress difference at each of the first reference points is located in a direction perpendicular to the length of the first belt-like regions. Lines connecting adjacent ones of the first reference points form a center line, as a reference line, of each of the first belt-like regions. Each of the second belt-like regions contain a plurality of second reference points, each having a second principal stress difference which is larger than principal stress differences at areas of each of the second belt-like regions which are peripheral to each of the second reference points. The second principal stress difference extends in at least two different directions, one direction being substantially perpendicular to the first direction of the first principal stress difference and being located at peripheral edges of each of the second belt-like regions, and another direction being oblique to the first direction of the first principal stress difference. The two different directions of the second reference points forms a pattern. The pattern is a snaking line having undulations which are approximately trapezoidally-shaped.
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