Abstract Optical glass, nd = 1.650 ± 2 × 10.sup. -3 and vd = 55.5 ± 1.0, having a high chemical stability and a sufficiently low tendency toward crystallization that it can be manufactured in a continuous tank melting process into gobs, pressed components, and other formed articles as a mass-produced glass, said glass consisting essentially of, in percent by weight: SiO.sub.2 33.0 ± 0.5
B 2 O 3 11.6 ±
0.5
BaO 36.6 ±
1.0
La 2 O 3 14.0 ±
2.5
ZrO 2 4.0 ±
2.5
As 2 O 3 0 - 0.5.
or Sb 2 O 3
Optical glass, nd = 1.650 ± 2 × 10.sup. -3 and vd = 55.5 ± 1.0, having a high chemical stability and a sufficiently low tendency toward crystallization that it can be manufactured in a continuous tank melting process into gobs, pressed components, and other formed articles as a mass-produced glass, said glass consisting essentially of, in percent by weight: SiO.sub.2 33.0 ± 0.5
B.sub.2 O.sub.3 11.6 ± 0.5
BaO 36.6 ± 1.0
La.sub.2 O.sub.3
14.0 ± 2.5
ZrO.sub.2 4.0 ± 2.5
As.sub.2 O.sub.3
0 - 0.5.
or Sb.sub.2 O.sub.3
Claim 2
Dependent Claim
90 words
Optical glass, nd = 1.650 ± 2 × 10.sup. -3 and vd = 55.5 ± 1.0, having a high chemical stability and a sufficiently low tendency toward crystallization that it can be manufactured in a continuous tank melting process into gobs, pressed components, and other formed articles as a mass-produced glass, said glass consisting essentially of, in percent by weight: SiO.sub.2 33.0 ± 0.5
B.sub.2 O.sub.3 11.6 ± 0.5
BaO 36.6 ± 1.0
La.sub.2 O.sub.3
14.0 ± 2.5
ZrO.sub.2 4.0 ± 2.5
As.sub.2 O.sub.3
0 - 0.5.
or Sb.sub.2 O.sub.3
Claim 3
Dependent Claim
17 words
An optical glass according to claim 1, wherein nd = 1.650 ± 1 × 10.sup. -3 .
Claim 4
Dependent Claim
13 words
An optical glass according to claim 1, wherein vd = 55.0 ± 0.5.
Claim 5
Dependent Claim
13 words
An optical glass according to claim 2, wherein vd = 55.0 ± 0.5.
Claim 6
Dependent Claim
40 words
A glass composition consisting essentially of, in percent by weight: SiO.sub.2 33.0 ± 0.5
B.sub.2 O.sub.3 11.6 ± 0.5
BaO 36.6 ± 1.0
La.sub.2 O.sub.3
14.0 ± 2.5
ZrO.sub.2 4.0 ± 2.5
As.sub.2 O.sub.3
0 - 0.5
or Sb.sub.2 O.sub.3
Claim 7
Dependent Claim
40 words
A glass composition consisting essentially of, in percent by weight: SiO.sub.2 33.0 ± 0.5
B.sub.2 O.sub.3 11.6 ± 0.5
BaO 36.6 ± 1.0
La.sub.2 O.sub.3
14.0 ± 2.5
ZrO.sub.2 4.0 ± 2.5
As.sub.2 O.sub.3
0 - 0.5
or Sb.sub.2 O.sub.3
Claim 8
Dependent Claim
59 words
A glass composition according to claim 4, having the following properties: the coefficient of expansion α × 10 - 7 /° C. between 20° and 300° C. is 74 ± 2; the transformation temperature is 683 ± 5° C; the softening temperature at 10 7 .65 poises is 810 ± 10° C.; the specific gravity is 3.78 ± 0.05.