Alkali-free glass

Patent metadata

Field	Value
Publication number	US-11053160-B2
Application number	US-201916282363-A
Country	US
Kind code	B2
Filing date	Feb 22, 2019
Priority date	Aug 23, 2016
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

To provide an alkali-free glass, of which the compaction is low, the strain point is high, and the ultraviolet transmittance is high, and which is easy to melt.An alkali-free glass, which comprises, as represented by mol % based on oxides,SiO2from 65 to 75,Al2O3from 9 to 15,B2O3from 0 to 3,MgOfrom 0 to 12,CaOfrom 0 to 8,SrOfrom 0 to 6, andBaOfrom 0 to 5,wherein MgO+CaO+SrO+BaO is from 12 to 22, and 4.84[Fe2O3]+5.65[Na2O]+4.03[K2O]+4.55[SnO2] is at most 0.55, and of which the compaction is at most 80 ppm.

First claim

What is claimed is:

1. An alkali-free glass, comprising, as represented by mol % based on oxides,

SiO 2
from 65 to 75,

Al 2 O 3
from 9 to 15,

B 2 O 3
from 0 to 3,

MgO
from 5 to 12,

CaO
from 3 to 8,

SrO
from 1 to 6,

BaO
from 0 to 5,

Fe 2 O 3
from 0.001 to 0.03,

Na 2 O
from 0.003 to 0.06,

K 2 O
from 0 to 0.02,

SnO 2
from 0 to 0.12, and

ZrO 2
from 0 to 2,

wherein MgO+CaO+SrO+BaO is from 12 to 22, MgO/(MgO+CaO+SrO+BaO) is at least 0.33, MgO/(MgO+CaO) is at least 0.40, MgO/(MgO+SrO) is at least 0.45, and 4.84[Fe 2 O 3 ]+5.65[Na 2 O]+4.03[K 2 O]+4.55[SnO 2 ] is at most 0.55, and
wherein an average thermal expansion coefficient at from 50 to 350° C. is from 30×10 −7 to 45×10 −7 /° C.

2. The alkali-free glass according to claim 1 , wherein the alkali-free glass has a strain point of at least 690° C., a temperature T 2 at which a glass viscosity becomes 10 2 dPa·s of at most 1,710° C., and a temperature T 4 at which the glass viscosity becomes 10 4 dPa·s of at most 1.350° C.

3. The alkali-free glass according to claim 1 , wherein a strain point of the alkali-free glass is at least 725° C.

4. The alkali-free glass according to claim 1 , wherein a glass transition point of the alkali-free glass is at least 750° C.

5. The alkali-free glass according to claim 1 , wherein a compaction is at most 50 ppm.

6. The alkali-free glass according to claim 1 , wherein a compaction is at most 80 ppm.

7. The alkali-free glass according to claim 1 , wherein an ultraviolet transmittance of the alkali-free glass at the wavelength of 300 nm in the plate thickness of 0.5 mm is at least 40%.

8. The alkali-free glass according to claim 1 , of wherein a photoelastic constant of the alkali-free glass is at most 31 nm/MPa/cm.

9. The alkali-free glass according to claim 1 , wherein a β-OH value of the alkali-free glass is at most 0.45 mm −1 .

10. The alkali-free glass according to claim 1 , wherein a dielectric constant of the alkali-free glass is at least 5.6.

11. The alkali-free glass according to claim 1 , wherein a Young's modulus of the alkali-free glass is at least 82 GPa.

12. The alkali-free glass according to claim 1 , which is a substrate glass for displays.

13. A substrate glass for displays, comprising:
the alkali-free glass of claim 1 , and
a thin film of a metal or oxide on at least one surface.

14. The alkali free substrate glass according to claim 13 , wherein the substrate glass is used for a liquid crystal display device, an organic EL device, or a lighting device.

Assignees

• Agc Inc

Inventors

• Tokunaga Hirofumi
• Ono Kazutaka
• Hirose Motoyuki

Classifications

• C03C3/087 Primary

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

• C03C3/091 Primary

  containing aluminium · CPC title

• C03C3/093 Primary

  containing zinc or zirconium · CPC title

• C03C3/083 Primary

  containing aluminium oxide or an iron compound · CPC title

• C03C17/06

  with metals (C03C17/34, C03C17/44 take precedence) · CPC title