| CPC C03C 21/002 (2013.01) [C03C 3/085 (2013.01); C03C 3/097 (2013.01)] | 12 Claims |
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1. A tempered glass having a surface and a thickness T,
wherein, when a compressive stress of the tempered glass is represented by a positive number and a tensile stress thereof is represented by a negative number,
a maximum value of the compressive stress at the surface is 400 MPa or more,
a stress profile of the tempered glass obtained by measuring a stress in a depth direction from the surface has inflection points at each of which a second derivative of the stress profile becomes zero between the surface and a depth equal to a half of the thickness T, and
the compressive stress at a first inflection point present at a position closest to the surface among the inflection points is 150 MPa or less,
wherein the inflection points comprise a second inflection point present at a position deeper than the first inflection point, and
wherein (σ1−σ2)/(d1−d2) is −1.0 MPa/μm or more, where σ1 represents the stress at the first inflection point, d1 represents a depth of the first inflection point from the surface, σ2 represents the stress at the second inflection point, and d2 represents a depth of the second inflection point from the surface.
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