Boron aluminosilicate glass

• US 20040229743A1
• Filed: 02/27/2004
• Published: 11/18/2004
• Est. Priority Date: 03/12/2003
• Status: Active Grant

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Inventors: Kolberg, Uwe, Woelfel, Ute, Wolff, Silke, Kasprzik, Holger
• Granted Patent: US 7,323,427 B2
• Time in Patent Office: Days
• US Class Current: 501/67
• CPC Class Codes: C03C 13/046 Multicomponent glass compositions
• CPC Class Codes: C03C 3/066 containing zinc
• CPC Class Codes: C03C 3/068 containing rare earths
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/093 containing zinc or zirconium
• CPC Class Codes: C03C 3/095 containing rare earths

Abstract

A short optical glass is disclosed which is particularly suited for the applications imaging, projection, telecommunication, optical information technology and/or laser technology, also particularly suited for fiber applications (light guides or imaging guides). Preferably, the glass has a refractive index of 1.54≦n_d≦1.62 and an Abbe coefficient of 48≦v_d=57. It further has good attenuating and ion exchange characteristics, good chemical stability and good crystallization stability. The glass comprises 35 to 50 wt.-% SiO₂, 0.1 to 6 wt.-% B₂O₃, 0.1 to 7 wt.-% Al₂O₃, 0.1 to 4 wt.-% P₂O₅, 4 to 24 wt.-% R₂O (alkali oxides), 6 to 14.5 wt.-% BaO, 0 to 12 wt.-% other RO (alkaline earth oxides), 14 to 25 wt.-% ZnO, 0 to 5 wt.-% La₂O₃, 0 to 10 wt.-% ZrO₂, wherein R₂O is an alkali oxide, RO is an alkaline earth oxide other than BaO, wherein Li₂O is 6 wt.-% at the most, wherein the glass does not contain any GeO₂, SnO, SnO₂, AgO, Sb₂O₃ and, preferably, no rare earth oxides, and wherein the glass may be molten while adding suitable purifying agents.

Claims

1. A boron aluminosilicate glass comprising at least the following components (in wt.-%):

2. The boron aluminosilicate glass of claim 1 comprising in wt.-%):

3. A boron aluminosilicate glass comprising at least the following components (in wt.-%):

4. The boron aluminosilicate glass of claim 3, comprising the following components (in wt.-%):

5. A boron aluminosilicate glass comprising (in wt.-%):

6. The boron aluminosilicate glass of claim 5 which comprises up to 1 wt.-% of refining agents.

7. The boron aluminosilicate glass of claim 6, wherein said refining agents comprise at least one component selected from the group formed by Sb₂O₃, As₂O₃, SnO, NaCl, SO₄²⁻

and F⁻

.

8. The boron aluminosilicate glass of claim 5 comprising (in wt.-%):

9. The boron aluminosilicate glass of claim 7, wherein the portion of RO in the total weight is smaller than the portion of BaO.

10. The boron aluminosilicate glass of claim 5, comprising at least the following components (in wt.-%):

11. The boron aluminosilicate glass of claim 5 having a refractive index n_d of 1.54=n_d=1.62.

12. The boron aluminosilicate glass of claim 5 having an Abbe number of 48=v_d=57.

13. An optical stepped-index fiber comprising a core glass according to claim 5, and further comprising a cladding glass fully enclosing an outer surface of said core glass and having a numerical aperture of 0.28 to 0.70.

14. The optical stepped-index fiber of claim 13, wherein said cladding glass comprises (in wt.-%):

15. The optical stepped-index fiber of claim 13, wherein said cladding glass comprises (in wt.-%):

16. The optical stepped-index fiber of claim 13, wherein said cladding glass, apart from any unintended contaminants, does not contain any Cs₂O.

17. The optical stepped-index fiber of claim 13, wherein in said cladding glass the sum of the components Na₂O, Li₂O and K₂O is smaller than 3 wt.-%.

18. The optical stepped-index fiber of claim 17 wherein in said cladding glass the content of SiO₂ is between 66 and 72 wt.-%.