Alkali-free aluminoborosilicate glass and its use

• US 5,770,535 A
• Filed: 01/31/1997
• Issued: 06/23/1998
• Est. Priority Date: 02/02/1996
• Status: Expired due to Fees

• Current Assignee: Schott Glaswerke
• Original Assignee: Schott Glaswerke
• Inventors: Schneider, Klaus, Brix, Peter, Lautenschlager, Gerhard, Kloss, Thomas
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US08/791,949
• Time in Patent Office: 508 Days
• Field of Search: 501/67, 501/70
• US Class Current: 501/67
• CPC Class Codes: C03C 1/004 Refining agents refining C03B5/225
• CPC Class Codes: C03C 3/093 containing zinc or zirconium

Abstract

An alkali-free aluminoborosilicate glass preferably with a thermal expansion α_20/300 of about 3.7 ×10^-6 /K, an annealing temperature OKP of above 700° C., a treatment temperature V_A of less than 1220° C., and very good chemical stability, which can be produced in a float unit and has the following composition (in % by weight based on oxide): SiO₂ 52-62; B₂ O₃ 4-14; Al₂ O₃ 12-20; MgO 0-8; CaO 4-11; BaO 0-2; ZnO 2-8; ZrO₂ 0-2; SnO₂ 0-2. The ratio of Al₂ O₃ /B₂ O₃ is preferably equal to or greater than 3. The glass is especially suitable for use in display technology.

Claims

1. Alkali-free aluminoborosilicate glass of the following composition, in % by weight based on oxide:

SiO₂ 52-62

B₂ O₃ 4-14

Al₂ O₃ 12-20

MgO 0-8

CaO 4-11

BaO 0-2

ZnO 2-8

ZrO₂ 0-2

SaO₂ 052 0-2.

2. Aluminoborosilicate glass according to claim 1 with a composition, in % by weight based on oxide, of

SiO₂ 55-60

B₂ O₃ 5-12

Al₂ O₃ 15-18

MgO 0-6

CaO 6-10

BaO 0-1

ZnO 2-6

ZrO₂ 0-2

SnO₂ 0.5-1.

3. Aluminoborosilicate glass according to claim 1 with a ratio by weight of Al₂ O₃ :

B₂ O₃ ≧

3.

4. Aluminoborosilicate glass according to claim 1 with a molar ratio of CaO:

MgO=1.

5. Aluminoborosilicate glass of claim 1, having a thermal expansion of α

_20/300 of about 3.7×

10^-6 /K, an annealing temperature OKP of above 700°

C., a treatment temperature V_A of less than 1220°

C. and a very good chemical stability.

6. Aluminoborosilicate glass of claim 5, produced by a float glass process.

7. A display comprising a display screen of the glass of claim 1.

8. The display of claim 7, wherein the display screen is a flat panel display screen.

9. An aluminoborosilicate glass of claim 1, having a thermal expansion, α

_20/300, of about 3.7×

10^-6 /K.

10. An aluminoborosilicate glass of claim 1, having an annealing temperature, OKP, of above 700°

C.

11. An aluminoborosilicate glass of claim 1, having a treatment temperature, V_A, of less than 1200°

C.

12. An aluminoborosilicate glass of claim 1, having a hydrolytic resistance according to ISO 719 of about 12-13 μ

g of Na₂ O/g.

13. An aluminoborosilicate glass of claim 1, having no BaO content.