Aluminosilicate glass
View Patent ↗A short optical glass is disclosed which does not comprise any silver, copper, thallium, lead or boron and is particularly suited for the application 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 1.55≦n d ≦1.65 and an Abbe coefficient of 48≦v d ≦57 and also has good attenuating and ion exchange characteristics, good chemical stability and good crystallization stability. The glass comprises 35 to <50 wt.-% SiO 2 ; 1 to 10 wt.-% Al 2 O 3 ; 5 to 15 wt.-% Na 2 O+K 2 O+CS 2 O+Li 2 O; 20 to 30 wt.-% BaO; 0 to 15 wt.-% ZnO; 0 to 10 wt.-% La 2 O 3 ; 0 to 10 wt.-% ZrO 2 ; 0 to 6 wt.-% P 2 O 5 ; 0 to 8 wt.-% MgO+CaO+SrO; 0 to 3 wt.-% of other oxides, and Cs 2 O<1, Li 2 O<1, and TiO 2 <1 wt.-%.
1. An aluminosilicate glass comprising (in wt.-%):
SiO 2
39 to 45
Al 2 O 3
3 to 7
Na 2 O + K 2 O + Cs 2 O + Li 2 O
5 to 15
BaO
24 to <30
ZnO
5 to 10
La 2 O 3
2 to 7
ZrO 2
2 to 7
P 2 O 5
0 to 6
and
MgO + CaO
0 to 8,
wherein the sum of Na 2 O and K 2 O is 8 to 12 wt.-%.
2. An aluminosilicate glass consisting of (in wt.-%):
SiO 2
35 to <50
Al 2 O 3
1 to 10
Na 2 O + K 2 O + Cs 2 O + Li 2 O
5 to 15
the Na 2 O + K 2 O + Cs 2 O + Li 2 O providing less than
1 wt. % Cs 2 O and less than 1 wt. % Li 2 O to the glass
BaO
20 to 30
ZnO
0 to 15
La 2 O 3
1 to 10
ZrO 2
0 to 10
TiO 2
<1
P 2 O 5
0 to 6
MgO + CaO + SrO
0 to 8
and
at least one refining agent residue
0 to 1.
3. The aluminosilicate glass of claim 2 wherein said glass is at least substantially free of TiO 2, Li 2 O and Cs 2 O.
4. The aluminosilicate glass of claim 2 , consisting of (in wt.-%):
SiO 2
35 to <50
Al 2 O 3
1 to 10
Na 2 O + K 2 O
5 to 15
BaO
20 to 30
ZnO
1 to 15
La 2 O 3
1 to 10
ZrO 2
1 to 10
P 2 O 5
0 to 6
MgO + CaO
0 to 8
and
at least one refining agent residue
0 to 1,
wherein the amount of Na 2 O is at least 5 wt.-%.
5. The aluminosilicate glass of claim 4 , consisting of (in wt.-%):
SiO 2
35 to <50
Al 2 O 3
1 to 10
Na 2 O + K 2 O
5 to 15
BaO
20 to 30
ZnO
1 to 15
La 2 O 3
1 to 10
ZrO 2
1 to 10
P 2 O 5
0 to 6
and
MgO + CaO
0 to 8.
6. The aluminosilicate glass of claim 2 , wherein said refining agent residue is obtained from a refining agent that is any one or more of Sb 2 O 3 , As 2 O 3 , SnO, NaCl, SO 4 −− and F − .
7. The aluminosilicate glass of claim 2 , consisting of (in wt.-%):
SiO 2
35 to 48
Al 2 O 3
1 to 10
Na 2 O + K 2 O
5 to 15
BaO
20 to <30
ZnO
1 to 12
La 2 O 3
1 to 10
ZrO 2
1 to 10
P 2 O 5
0 to 6
and
MgO + CaO
0 to 8.
8. The aluminosilicate glass of claim 2 , consisting of (in wt.-%):
SiO 2
35 to 45
Al 2 O 3
2 to 7
Na 2 O + K 2 O
6 to 12
BaO
20 to <30
ZnO
5 to 10
La 2 O 3
1 to 7
ZrO 2
1 to 10
P 2 O 5
0 to 6
and
MgO + CaO
0 to 8.
9. The aluminosilicate glass of claim 2 , consisting of (in wt.-%):
SiO 2
37 to 45
Al 2 O 3
3 to 7
Na 2 O + K 2 O
8 to 12
BaO
22 to <30
ZnO
5 to 10
La 2 O 3
2 to 7
ZrO 2
2 to 7
P 2 O 5
0 to 6
and
MgO + CaO
0 to 8.
10. The aluminosilicate glass of claim 2 , consisting of (in wt.-%):
SiO 2
39 to 45
Al 2 O 3
3 to 7
Na 2 O + K 2 O
8 to 12
BaO
24 to <30
ZnO
5 to 10
La 2 O 3
2 to 7
ZrO 2
2 to 7
P 2 O 5
0 to 6
and
MgO + CaO
0 to 8.
11. The aluminosilicate glass of claim 2 having a refractive index n d of 1.55≦n d ≦1.65 and an Abbe number of 48≦v d ≦57.
12. An optical stepped-index fiber comprising a core glass fiber and fully clad at an outer surface thereof by a cladding glass, said optical step index fiber having a numerical aperture of 0.30 to 0.75 and comprising a core glass fiber consisting of (in wt.-%):
SiO 2
35 to <50
Al 2 O 3
1 to 10
Na 2 O + K 2 O + Cs 2 O + Li 2 O
5 to 15
the Na 2 O + K 2 O + Cs 2 O + Li 2 O providing less than 1
wt. % Cs 2 O and less than 1 wt. % Li 2 O to the glass
BaO
20 to 30
ZnO
0 to 15
La 2 O 3
1 to 10
ZrO 2
0 to 10
TiO 2
<1
P 2 O 5
0 to 6
MgO + CaO + SrO
0 to 8
and
at least one refining agent residue
0 to 1.
13. The optical stepped-index fiber of claim 12 , wherein said cladding glass comprises (in wt.-%):
SiO 2
60 to 72
B 2 O 3
<20
Na 2 O
<18
K 2 O
<15
Li 2 O
<2
MgO
<3
BaO
<3
SrO
<4
CaO
<6
ZnO
<3
and
F −
<1.
14. The optical stepped-index fiber of claim 13 , wherein said cladding glass, apart from any unintended contaminants, is free of Cs 2 O.
15. The optical stepped-index fiber of claim 12 , wherein the sum of the components Na 2 O, Li 2 O and K 2 O is smaller than 3 wt.-%.
16. The optical stepped-index fiber of claim 12 , wherein the content of SiO 2 in said cladding glass is between 66 and 72 wt.-%.