Glass plate for display device, plate glass for display device and production process thereof

Abstract

A process for producing a plate glass for a display device having a thickness of at most 1.5 mm by a float process, wherein the plate glass comprises, as represented by mole percentage based on the following oxides, from 67 to 75% of SiO 2 , from 0 to 4% of Al 2 O 3 , from 7 to 15% of Na 2 O, from 1 to 9% of K 2 O, from 6 to 14% of MgO and from 0 to 1.5% of ZrO 2 , has a total content of SiO 2 and Al 2 O 3 of from 71 to 75%, has a total content Na 2 O+K 2 O of Na 2 O and K 2 O of from 12 to 20%, and has a content of CaO of less than 1% if contained.

1 . A process for producing a plate glass for a display device having a thickness of at most 1.5 mm by a float process, wherein the plate glass comprises, as represented by mole percentage based on the following oxides, from 67 to 75% of SiO 2 , from 0 to 4% of Al 2 O 3 , from 7 to 15% of Na 2 O, from 1 to 9% of K 2 O, from 6 to 14% of MgO and from 0 to 1.5% of ZrO 2 , has a total content of SiO 2  and Al 2 O 3  of from 71 to 75%, has a total content Na 2 O+K 2 O of Na 2 O and K 2 O of from 12 to 20%, and has a content of CaO of less than 1% if contained. 
     
     
         2 . The process for producing a plate glass for a display device according to  claim 1 , wherein the SiO 2  content of the plate glass is from 69 to 74%. 
     
     
         3 . The process for producing a plate glass for a display device according to  claim 1 , wherein the Al 2 O 3  content of the plate glass is at least 0% and less than 3%. 
     
     
         4 . The process for producing a plate glass for a display device according to  claim 1 , wherein the MgO content of the plate glass is from 8 to 13%. 
     
     
         5 . The process for producing a plate glass for a display device according to  claim 1 , wherein the total content Na 2 O+K 2 O of the plate glass is higher than 13.5%. 
     
     
         6 . The process for producing a plate glass for a display device according to  claim 1 , wherein when the plate glass contains at least one component of CaO, SrO, BaO and ZrO 2 , the total content of these four components is less than 1.5%. 
     
     
         7 . The process for producing a plate glass for a display device according to  claim 1 , wherein the B 2 O 3  content of the plate glass is less than 1% if contained. 
     
     
         8 . The process for producing a plate glass for a display device according to  claim 1 , wherein the temperature at which the viscosity of the plate glass is 10 2  dPa·s is at most 1,650° C. 
     
     
         9 . The process for producing a plate glass for a display device according to  claim 1 , wherein the average linear expansion coefficient of the plate glass at from 50 to 350° C. is higher than 86×10 −7 /° C. 
     
     
         10 . A plate glass for a display device having a thickness of at most 1.5 mm, comprising, as represented by mole percentage based on the following oxides, from 67 to 75% of SiO 2 , from 0 to 4% of Al 2 O 3 , from 7 to 15% of Na 2 O, from 1 to 9% of K 2 O, from 6 to 14% of MgO and from 0 to 1.5% of ZrO 2 , having a total content of SiO 2  and Al 2 O 3  of from 71 to 75%, having a total content Na 2 O+K 2 O of Na 2 O and K 2 O of from 12 to 20%, and having a content of CaO of less than 1% if contained. 
     
     
         11 . The plate glass for a display device according to  claim 10 , which has an Al 2 O 3  content of at least 0% and less than 3%. 
     
     
         12 . The plate glass for a display device according to  claim 10 , which has a total content Na 2 O+K 2 O of higher than 13.5%. 
     
     
         13 . The plate glass for a display device according to  claim 10 , which has an average linear expansion coefficient at from 50 to 350° C. of higher than 86×10 −7 /° C. 
     
     
         14 . A glass plate for a display device, obtained by chemically tempering a glass plate having a thickness of at most 1 mm, comprising, as represented by mole percentage based on the following oxides, from 67 to 75% of SiO 2 , from 0 to 4% of Al 2 O 3 , from 7 to 15% of Na 2 O, from 1 to 9% of K 2 O, from 6 to 14% of MgO, and from 0 to 1.5% of ZrO 2 , having a total content of SiO 2  and Al 2 O 3  of from 71 to 75%, having a total content Na 2 O+K 2 O of Na 2 O and K 2 O of from 12 to 20%, and having a content of CaO of less than 1% if contained. 
     
     
         15 . A cover glass for a display device, comprising the glass plate for a display device as defined in  claim 14 . 
     
     
         16 . The cover glass according to  claim 15 , wherein the display device is a mobile device. 
     
     
         17 . The cover glass according to  claim 15 , wherein the display device is a touch panel.