Cover glass and method for producing cover glass

Patent metadata

Field	Value
Publication number	US-9434644-B2
Application number	US-201113247627-A
Country	US
Kind code	B2
Filing date	Sep 28, 2011
Priority date	Sep 30, 2010
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

The disclosed cover glass is produced by etching a glass substrate that has been formed by a down-drawing process, and chemically strengthening the glass substrate to provide the glass substrate with a compressive-stress layer on the principal surfaces thereof. The glass substrate contains, as components thereof, 50% to 70% by mass of SiO 2 , 5% to 20% by mass of Al 2 O 3 , 6% to 30% by mass of Na 2 O, and 0% to less than 8% by mass of Li 2 O. The glass substrate may also contain 0% to 2.6% by mass of CaO, if necessary. The glass substrate has an etching characteristic in which the etching rate is at least 3.7 μm/minute in an etching environment having a temperature of 22° C. and containing hydrogen fluoride with a concentration of 10% by mass.

First claim

What is claimed is:

1. A cover glass comprising:
a plate-shaped glass substrate having a compressive-stress layer on principal surfaces thereof,
the glass substrate containing, as components thereof, 50% to 67% by mass of SiO 2 , 5% to 20% by mass of Al 2 O 3 , 10% to 15.4% by mass of Na 2 O, 0% to 1% by mass of Li 2 O, 0% to less than 4% by mass of K 2 O, substantially no CaO, 0% to less than 0.1% by mass of ZrO 2 , 0% to 1% by mass of TiO 2 , 0% to 5% by mass of B 2 O 3 , and greater than 1% to 15% by mass of MgO,
the ratio of the content of K 2 O to R 2 O (K 2 O/R 2 O) of the substrate being from 0 to 0.08, and
the ratio of the content of ZrO 2 and TiO 2 to SiO 2 ((ZrO 2 +TiO 2 )/SiO 2 ) of the substrate being from 0 to 0.01, and if the content by percentage of the SiO 2 is X % by mass and the content by percentage of the Al 2 O 3 is Y % by mass, X-½·Y is 45% to 57.5% by mass.

2. The cover glass according to claim 1 , wherein the compressive-stress layer is formed on an end surface of the cover glass.

3. The cover glass according to claim 1 , wherein the glass substrate has an etching characteristic in which an etching rate is at least 3.7 μm/minute in an etching environment having a temperature of 22° C. and containing hydrogen fluoride with a concentration of 10% by mass.

4. The cover glass according to claim 1 , wherein the glass substrate is formed into a plate-like shape by a down-drawing process.

5. The cover glass according to claim 1 , wherein the glass substrate contains substantially no K 2 O.

6. The cover glass according to claim 1 , wherein the glass substrate has a strain point of 580° C. or more.

7. The cover glass according to claim 1 , wherein the depth of the compressive stress layer range is 47.7 μm to 90.0 μm.

Assignees

• Koyama Akihiro
• Morishita Mikiko
• Ami Satoshi
• Hashimoto Kazuaki
• Takano Tetsuo
• Avanstrate Inc
• Hoya Corp

Inventors

• Koyama Akihiro
• Morishita Mikiko
• Ami Satoshi
• Hashimoto Kazuaki
• Takano Tetsuo

Classifications

• C03C21/002 Primary

  to perform ion-exchange between alkali ions (C03C21/005 takes precedence) · CPC title

• C03C15/02

  for making a smooth surface · CPC title

• C03C3/087

  containing calcium oxide, e.g. common sheet or container glass · CPC title

• C03C15/00

  Surface treatment of glass, not in the form of fibres or filaments, by etching (etching or surface-brightening compositions, in general C09K13/00) · CPC title

• C03C3/083

  containing aluminium oxide or an iron compound · CPC title