Strengthened glass with deep depth of compression

摘要

Chemically strengthened glass articles having at least one deep compressive layer extending from a surface of the article to a depth of at least about 45 μm within the article are provided. In one embodiment, the compressive stress profile includes a single linear segment extending from the surface to the depth of compression DOC. Alternatively, the compressive stress profile includes two linear portions: the first portion extending from the surface to a relatively shallow depth and having a steep slope; and a second portion extending from the shallow depth to the depth of compression. The strengthened glass has a 60% survival rate when dropped from a height of 80 cm in an inverted ball drop test and an equibiaxial flexural strength of at least 10 kgf as determined by abraded ring-on-ring testing. Methods of achieving such stress profiles are also described.

主权项

1. A glass article having a thickness t, the glass article comprising:
a compressive layer having a compressive stress CS in a range from about 500 MPa up to about 1200 MPa at a surface of the glass article, wherein:
a. the compressive layer extends from the surface to a depth of compression DOC, wherein DOC≧0.1·t when t<0.5 mm and DOC≧50 μm when t≧0.5 mm, and wherein the compressive layer has a compressive stress profile; andb. the compressive stress profile comprises:
i. a first portion h extending from the surface to a depth db and having an average slope mb, wherein 3 μm≦db≦15 μm and −40 MPa/μm≧mb≧−200 MPa/μm and wherein the first portion b is linear such thatσ″⁡(x)<2⁢σ′⁡(x)db  where σ″(x) is the second derivative of the stress profile in the first portion h with respect to depth x and σ′(x) is the first derivative of the stress profile in the first portion b with respect to depth x;
ii. a second portion c extending from db to the DOC and having an average slope mc, wherein −2 MPa/μm≧mc≧−8 MPa/μm and wherein the second portion c is linear such thatσ″⁡(x)<2⁢σ′⁡(x)D⁢⁢O⁢⁢Cwhere σ″(x) is the second derivative of the stress profile in the second portion e with respect to depth x and σ′(x) is the first derivative of the stress profile in the second portion c with respect to depth x.