Patent ID: 11878941
Assignee: CORNING INCORPORATED
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A glass, the glass being ion-exchanged and comprising:
a. a compressive layer extending from a surface of the glass to a depth of compression DOC, the compressive surface layer having a maximum compressive stress CS;
b. a central region having a maximum physical central tension CT at a centre of the glass, the central region extending outward from the centre of the glass to the depth of compression, wherein the glass has an average elastic energy density of less than 200 J/m2·mm;
a thickness t in a range from 0.3 mm to 1.0 mm, wherein DOC≥0.08·t and; and wherein:
i. the physical central tension CT is greater than 0.681×(57−9.0×ln(t)+49.3×(ln(t)2) when 0.3 mm≤t≤0.5 mm, wherein the unit of 57 is MPa, the unit of −9.0 is MPa/mm, the unit of ln(t) is mm, the unit of 49.3 is MPa/mm and the unit of (ln(t))2 is mm;
ii. the physical central tension CT is greater than 0.728×(57−9.0×ln(t)+49.3×(ln(t)2) when 0.5 mm≤t≤0.7 mm, wherein the unit of 57 is MPa, the unit of −9.0 is MPa/mm, the unit of ln(t) is mm, the unit of 49.3 is MPa/mm and the unit of (ln(t))2 is mm;
iii. the physical central tension CT is greater than 0.755×(−38.7×ln(t)+48.2) when 0.7 mm<t≤1.0 mm, wherein the unit of −38.7 is MPa/mm, the unit of ln(t) is mm, and the unit of 48.2 is MPa; and
iv. the glass has a total normalized energy, W
    norm
    tot
  
  =
  
    
      
        W
        el
        tot
      
      
        (
        
          
            1
            -
            v
          
          E
        
        )
      
    
    =
    
      
        ∫
        0
        Thickness
      
      ⁢
      
        
          σ
          2
        
        ⁢
        dx, per unit thickness of less than or equal to 37.5×103 MPa2μm, wherein v is the Poisson ratio, E is Young's modulus, σ is the stress, and x is the depth.