Glass plate and process for its production

摘要

A cover glass includes a soda lime silica glass including SiO2, MgO, CaO, Na2O and Al2O3. The SiO2 content in the silica glass is in the range of 60 wt % to 71.1 wt %, the MgO content in the silica glass in the range of 4.5 wt % to 15 wt %, the CaO content in the silica glass in the range of 0.5 wt % to 10 wt %, the Na2O content in the silica glass in the range of 10-20 wt %, the Al2O3 content in the silica glass in the range of 0-10.3 wt %, the silica glass has the ratio [MgO]/[CaO] of larger than 1 and the Q value of 20 or larger, and the Q value is obtained by formula, Q =([MgO]/[CaO])X([CaO]+[Na2O]−[Al2O3]), where [MgO] is the MgO content, [CaO] is the CaO content, [Na2O] is the Na2O content, and [Al2O3] is the Al2O3 content by mass percentage based on oxides.

主权项

1. A cover glass, comprising:
a soda lime silica glass comprising Si02, MgO, CaO, Na2O and Al2O3, wherein a content of SiO2 in the soda lime silica glass is in a range of 60 wt % to 71.1 wt % , a content of MgO in the soda lime silica glass is in a range of 4.5 wt % to 15 wt % , a content of CaO in the soda lime silica glass is in a range of 0.5 wt % to 10 wt % , a content of Na2O in the soda lime silica glass is in a range of 10-20 wt % , a content of Al2O3 in the soda lime silica glass is in a range of 0-10.3 wt % , a content of B2O3 is at most 1 wt %, the soda lime silica glass has a ratio [MgO]/[CaO] of larger than 1 and a Q value of at least 20, and the Q value is obtained by formula of Q =([MgO]/[CaO])X([CaO]+[Na2O]−[Al2O3]),where [MgO] is the content of MgO by mass percentage based on oxide, [CaO] is the content of CaO by mass percentage based on oxide, [Na2O] is the content of Na2O by mass percentage based on oxide, and [Al2O3] is the content of Al2O3 by mass percentage based on oxide.