Glass sheet

Abstract

A glass sheet includes, as represented by mole percentage based on oxides, from 55.5 to 80% of SiO 2 , from 12 to 20% of Al 2 O 3 , from 8 to 25% of Na 2 O, 2.5% or more of P 2 O 5 , and 1% or more of an alkaline earth metal RO (RO is MgO+CaO+SrO+BaO).

1 - 7 : (canceled) 
     
     
         8 . A glass sheet comprising, as represented by mole percentage based on oxides, from 59 to 72.5% of SiO 2 , from 12 to 20% of Al 2 O 3 , from 8 to 17% of Na 2 O, more than 0% and 4.0% or less of P 2 O 5 , from 0 to 3% of MgO, from 0 to 3% of SrO, from 0 to 3% of BaO, and from 0 to 3% of K 2 O,
 wherein, when an indentation is formed by using a Vickers indenter, a pressing load of the Vickers indenter at which an incidence of cracking is 50% is equal to or more than 300 gf.   
     
     
         9 . The glass sheet according to  claim 8 , wherein a depth at which a hydrogen amount is 1.05 times a bulk value thereof is equal to or more than 500 nm from a surface of the glass sheet. 
     
     
         10 . The glass sheet according to  claim 8 , wherein an average value of a hydrogen amount in a depth of from 500 nm to 1,000 nm from a surface of the glass sheet is equal to or more than 1.5 times a bulk value thereof. 
     
     
         11 . The glass sheet according to  claim 8 , wherein a content of SiO2 is 61% or more. 
     
     
         12 . The glass sheet according to  claim 8 , wherein a content of CaO is 1% or less. 
     
     
         13 . The glass sheet according to  claim 8 , wherein SrO is not contained. 
     
     
         14 . The glass sheet according to  claim 8 , wherein BaO is not contained. 
     
     
         15 . The glass sheet according to  claim 8 , further comprising 1% or more of an alkaline earth metal RO. 
     
     
         16 . The glass sheet according to  claim 8 , wherein a content of MgO is 1.5% or less.