Method of reducing warpage generated in glass plate by chemical strengthening treatment, method of manufacturing glass plate for chemical strengthening and method of manufacturing chemically strengthened glass plate

摘要

The present invention is a method for reducing warping of the glass sheet generated by subjecting a glass plate produced by a float process to a chemical strengthening treatment. In the method of the present invention, before the chemical strengthening treatment is applied, the glass plate produced by the float method is held in the temperature range of strain point of-70 C. to strain point + 20 C. of the glass for 10 minutes or longer .