Method for producing toughened glass plate

Patent metadata

Field	Value
Publication number	US-10329193-B2
Application number	US-201414892363-A
Country	US
Kind code	B2
Filing date	May 22, 2014
Priority date	May 24, 2013
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

A method of manufacturing a tempered glass sheet of the present invention includes: subjecting a glass sheet to be tempered having a sheet thickness of 2.0 mm or less to ion exchange treatment; and performing heat treatment at a temperature of 50° C. or more and less than a strain point of the glass sheet to be tempered.

First claim

The invention claimed is:

1. A method of manufacturing a tempered glass sheet, comprising:
subjecting a glass sheet to be tempered having a sheet thickness of 2.0 mm or less to ion exchange treatment;
then cooling the glass sheet to be tempered to a temperature of 80° C. or less after the ion exchange treatment;
then measuring a warpage of the glass sheet to be tempered after the cooling; and
then performing heat treatment on the glass sheet to be tempered at a temperature of 100° C. or more and less than a strain point of the glass sheet to be tempered after measuring the warpage.

2. The method of manufacturing a tempered glass sheet according to claim 1 , wherein
the ion exchange treatment is performed with use of an ion exchange solution containing a KNO 3 molten salt; and
the heat treatment is performed so that a value of (internal K emission intensity)/(surface layer K emission intensity) becomes from more than 0.67 to 0.95.

3. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the heat treatment is performed at a temperature of 100° C. or more and less than (strain point-200°) C.

4. The method of manufacturing a tempered glass sheet according to claim 1 , further comprising a step of cutting the tempered glass sheet to a predetermined size after the heat treatment.

5. The method of manufacturing a tempered glass sheet according to claim 1 , comprising a step of cutting the tempered glass sheet to a predetermined size after the ion exchange treatment and before the heat treatment.

6. The method of manufacturing a tempered glass sheet according to claim 1 , comprising a step of cutting the tempered glass sheet to a predetermined size before the ion exchange treatment.

7. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the glass sheet to be tempered is formed by an overflow down-draw method or a float method.

8. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the step of subjecting a glass sheet to be tempered to ion exchange treatment is performed so that a compressive stress of a compressive stress layer of the tempered glass sheet is 400 MPa or more, and a depth of layer of the compressive stress layer is 15 μm or more.

9. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the glass sheet to be tempered is produced so as to comprise 1 mass % to 20 mass % of Na 2 O in a glass composition.

10. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the glass sheet to be tempered is produced so as to comprise as a glass composition, in terms of mass %, 50% to 80% of SiO 2 , 5% to 25% of Al 2 O 3 , 0% to 15% of B 2 O 3 , 1% to 20% of Na 2 O, and 0% to 10% of K 2 O.

11. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the glass sheet to be tempered is produced so as to have a strain point of 500° C. or more.

12. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the glass sheet to be tempered is produced so as to have a β-OH value of 0.45/mm or less.

13. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the method is free of polishing a whole or a part of a surface of the tempered glass sheet.

14. The method of manufacturing a tempered glass sheet according to claim 1 , wherein the tempered glass sheet is used for a cover glass of a display device.

Assignees

• Nippon Electric Glass Co

Inventors

• Yasuda Hiroyuki
• Kobayashi Kozo
• Oka Takuji
• Toyofuku Naoki
• SERA Shigeru

Classifications

• C03C3/093

  containing zinc or zirconium · CPC title

• C03C21/002 Primary

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

• C03B29/025

  Glass sheets · CPC title

• C03C3/091

  containing aluminium · CPC title

• C03C3/087

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