US 12,269,768 B2
Glass-ceramic cover glass, process for production thereof and use thereof, and digital display device comprising such a cover glass
Ruediger Dietrich, Jena (DE); Bernd Ruedinger, Woerrstadt (DE); Meike Schneider, Taunusstein (DE); Jochen Alkemper, Klein-Winternheim (DE); Lars Mueller, Wiesbaden (DE); Thomas Pfeiffer, Ingelheim (DE); and Julian Koch, Mainz (DE)
Assigned to SCHOTT AG, Mainz (DE); and SCHOTT TECHNICAL GLASS SOLUTIONS GMBH, Jena (DE)
Filed by SCHOTT AG, Mainz (DE); and SCHOTT Technical Glass Solutions GmbH, Jena (DE)
Filed on Dec. 12, 2022, as Appl. No. 18/064,873.
Claims priority of application No. 10 2021 132 738.5 (DE), filed on Dec. 10, 2021; and application No. 10 2022 114 184.5 (DE), filed on Jun. 3, 2022.
Prior Publication US 2023/0183128 A1, Jun. 15, 2023
Int. Cl. C03C 10/00 (2006.01); C03B 32/02 (2006.01); C03C 3/083 (2006.01); C03C 3/085 (2006.01); C03C 3/087 (2006.01); C03C 21/00 (2006.01)
CPC C03C 10/0027 (2013.01) [C03B 32/02 (2013.01); C03C 3/083 (2013.01); C03C 3/085 (2013.01); C03C 3/087 (2013.01); C03C 10/0009 (2013.01); C03C 10/0054 (2013.01); C03C 21/002 (2013.01); C03C 2201/50 (2013.01); C03C 2203/20 (2013.01); C03C 2203/50 (2013.01); C03C 2204/00 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A cover glass comprising:
a chemically tempered silica based glass ceramic having two faces;
a thickness between the two faces of at least 0.4 mm and at most 0.85 mm;
a transmittance of more than 80% in a range from 380 nm to 780 nm; and
a stress attribute selected from a group consisting of: an overall compressive stress (CS) of at least 250 MPa and at most 1500 MPa, a compressive stress at a depth of 30 μm (CS30) from one of the two faces of at least 160 MPa and at most 525 MPa, a depth of the compression layer (DoCL) of at least 0.2 times the thickness and less than 0.5 times the thickness, and any combinations thereof,
wherein the chemically tempered silica based glass ceramic comprises at least one silica based crystal phase having in a near-surface layer of 20 μm to 70 μm, determined at a right angle from one of the two faces, a unit cell volume of at least 1% by volume larger than that of a core where the crystal phase has minimum stresses.