Abstract A phosphate optical glass, whose length of the light path is substantially independent of temperature, comprising, in % by weight, ______________________________________ P 2 O 5 27 - 55
K 2 O 6 - 26
BaO 10 - 50
K 2 O + BaO larger than 35
Al 2 O 3 2 - 15
TiO 2 + Nb 2 O 5 + Ta 2 O 5 4 - 20
TiO 2 0 - 14
Nb 2 O 5 0 - 20
Ta 2 O 5 0 - 7
B 2 O 3 0 - 5
Li 2 O 0 - 2
Na 2 O 0 - 5
MgO 0 - 6
CaO 0 - 8
SrO 0 - 10
ZnO 0 - 10
PbO 0 - 13, and
As 2 O 3 0 - 2 .
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A phosphate optical glass having an Abbe number in the range of 51 to 33, a refractive index (nd) of 1.57 to 1.68, and whose length of the light path is substantially independent of temperature, consisting essentially of in % by weight, ______________________________________
P.sub.2 O.sub.5 27 - 55
K.sub.2 O 6 - 26
BaO 10 - 50
K.sub.2 O + BaO larger than 35
Al.sub.2 O.sub.3 2 - 15
TiO.sub.2 + Nb.sub.2 O.sub.5 + Ta.sub.2 O.sub.5
4 - 20
TiO.sub.2 0 - 14
Nb.sub.2 O.sub.5 0 - 20
Ta.sub.2 O.sub.5 0 - 7
B.sub.2 O.sub.3 0 - 5
Li.sub.2 O 0 - 2
Na.sub.2 O 0 - 5
MgO 0 - 6
CaO 0 - 8
SrO 0 - 10
ZnO 0 - 10
PbO 0 - 13, and
As.sub.2 O.sub.3 0 - 2 .
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Claim 2
Dependent Claim
136 words
A phosphate optical glass having an Abbe number in the range of 51 to 33, a refractive index (nd) of 1.57 to 1.68, and whose length of the light path is substantially independent of temperature, consisting essentially of in % by weight, ______________________________________
P.sub.2 O.sub.5 27 - 55
K.sub.2 O 6 - 26
BaO 10 - 50
K.sub.2 O + BaO larger than 35
Al.sub.2 O.sub.3 2 - 15
TiO.sub.2 + Nb.sub.2 O.sub.5 + Ta.sub.2 O.sub.5
4 - 20
TiO.sub.2 0 - 14
Nb.sub.2 O.sub.5 0 - 20
Ta.sub.2 O.sub.5 0 - 7
B.sub.2 O.sub.3 0 - 5
Li.sub.2 O 0 - 2
Na.sub.2 O 0 - 5
MgO 0 - 6
CaO 0 - 8
SrO 0 - 10
ZnO 0 - 10
PbO 0 - 13, and
As.sub.2 O.sub.3 0 - 2 .
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