Alkali metal-free aluminoborosilicate glass and its use

• US 6,096,670 A
• Filed: 09/11/1998
• Issued: 08/01/2000
• Est. Priority Date: 09/11/1997
• Status: Expired due to Fees

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott Glaswerke
• Inventors: Schneider, Klaus, Brix, Peter, Lautenschlager, Gerhard, Kloss, Thomas
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US09/151,726
• Time in Patent Office: 690 Days
• Field of Search: 501/64, 501/67, 501/70, 428/426
• US Class Current: 501/67
• CPC Class Codes: C03C 1/004 Refining agents refining C03B5/225
• CPC Class Codes: C03C 3/095 containing rare earths

Abstract

An alkali metal-free aluminoborosilicate glass is described which has the following composition (in % by weight based on oxide):

SiO₂ 57-60; B₂ O₃ 6.5-9.5; Al₂ O₃ 14-17.5; MgO 5-8; CaO 1-4; SrO 5-8; BaO 0-3.5; with MgO+CaO+SrO+BaO 15-17; ZrO₂ 0.4-1.5; TiO₂ 0.4-1.5; CeO₂ 0.1-0.5; SnO₂ 0.2-1.

The glass is particularly suitable for use as a substrate glass in display technology.

Claims

1. An alkali metal-free aluminoborosilicate glass, which has the following composition in % by weight based on oxide:

space="preserve" listing-type="tabular">______________________________________ SiO.sub.2 57-60 B.sub.2 O.sub.3 6.5-9.5 Al.sub.2 O.sub.3 14-17.5 MgO 5-8 CaO 1-4 SrO 5-8 BaO 0-3.5 with MgO + CaO + SrO + BaO 15-17 ZrO.sub.2 0.4-1.5 TiO.sub.2 0.4-1 CeO.sub.2 0.1-0.5 SnO.sub.2 0.2-1. ______________________________________

2. The aluminoborosilicate glass according to claim 1, which is capable of being produced on a float system, and which is essentially free of arsenic oxide and antimony oxide.

3. The aluminoborosilicate glass according to claim 1, which further contains in % by weight based on oxide:

space="preserve" listing-type="tabular">______________________________________ As.sub.2 O.sub.3 0-1.5 Sb.sub.2 O.sub.3 0-1.5 Cl 0-1.5 F.sup.- 0-1.5 SO.sub.4 .sup.2- 0-1.5 ______________________________________

with As₂ O₃ +Sb₂ O₃ +Cl^- +F^- +SO₄^2- ≦

1.5.

4. The aluminoborosilicate glass according to claim 1, which has a coefficient of thermal expansion, α

_20/300, of from 3.5 to 3.8×

10^-6 /K, a temperature at the viscosity 10¹⁴.5 dPas of at least 650°

C., a temperature at the viscosity 10⁴ dPas of ≦

1280°

C., a density ρ

of at most 2.60 g/cm³ and a weight loss of at most 1.0 mg/cm² after 24 hours of treatment in 5% strength hydrochloric acid at 95°

C.

5. The aluminoborosilicate glass according to claim 3, which has a coefficient of thermal expansion, α

_20/300, of from 3.5 to 3.8×

10^-6 /K, a temperature at the viscosity 10¹⁴.5 dPas of at least 650°

C., a temperature at the viscosity 10⁴ dPas of ≦

1280°

C., a density ρ

of at most 2.60 g/cm³ and a weight loss of at most 1.0 mg/cm² after 24 hours of treatment in 5% strength hydrochloric acid at 95°

C.

6. The aluminoborosilicate glass of claim 1, which has a temperature at viscosity of 10⁴ dpas of 1230 to 1260°

C. and a v_MAX of no more than 10 μ

m/h.

7. The aluminoborosilicate glass of claim 2, which is further essentially free of P₂ O₅, Bi₂ O₃, PbO, CdO and ZnO, has a temperature at 10⁴ dpas viscosity of 1230 to 1280°

C. and has a v_MAX less than or equal to 30 μ

m/h.

8. The aluminoborosilicate glass of claim 1, which has a v_MAX of at most 5 μ

m/h, a processing temperature V_A from 1240 to 1320°

C.

9. A display glass substrate composed of an aluminoborosilicate glass of claim 1.

10. The display glass substrate of claim 9 which has a thickness of 30 μ

m to 2 mm.

11. A display glass substrate of claim 9 which is a TFT display glass substrate.