High index fluorine-free phosphate glasses
AssigneeCorning Incorporated
InventorBruce G. Aitken
Life of this patent
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Abstract
This invention is drawn to fluorine-free glasses having refractive indices of at least 1.65 which generally consist, in mole percent, of: ______________________________________ P.sub.2 O.sub.5 24-36 ZnO 0-45 Li.sub.2 O 0-15 Na.sub.2 O 0-20 K.sub.2 O 0-10 Ag.sub.2 O 0-25 Tl.sub.2 O 0-25 Li.sub.2 O + Na.sub.2 O + K.sub.2 O + Ag.sub.2 O + Tl.sub.2 O 15-30 PbO 0-20 CaO 0-20 CuO 0-5 CeO.sub.2 0-2 SrO 0-20 BaO 0-20 CaO + SrO + BaO 0-25 Sb.sub.2 O.sub.3 0-61 Bi.sub.2 O.sub.3 0-10 Sb.sub.2 O.sub.3 + Bi.sub.2 O.sub.3 0-61 Sb.sub.2 O.sub.3 + Bi.sub.2 O.sub.3 + Ag.sub.2 O + Tl.sub.2 O 7-76 SnO 0-5 Al.sub.2 O.sub.3 0-5 B.sub.2 O.sub.3 0-10 Al.sub.2 O.sub.3 + B.sub.2 O.sub.3 0-10 ______________________________________
Claims4
A glass having a composition which is essentially fluorine-free and which exhibits an annealing point between 300.degree.-340.degree. C., a linear coefficient of thermal expansion over the temperature interval 25.degree.-300.degree. C. between 135-180.times.10 .sup.-7 /.degree.C., a refractive index of at least 1.65, and a weight loss after exposure to boiling water for six hours no greater than 0.33% consisting essentially, expressed in terms of mole percent on the oxide basis, of:
- ______________________________________ P.sub.2 O.sub.5 24-36 ZnO 0-45 Li.sub.2 O 0-15 Na.sub.2 O 0-20 K.sub.2 O 0-10 Ag.sub.2 O 0-25 Tl.sub.2 O 0-25 Li.sub.2 O + Na.sub.2 O + K.sub.2 O + Ag.sub.2 O + Tl.sub.2 O 15-30 PbO 0-20 CaO 0-20 CuO 0-5 CeO.sub.2 0-2 SrO 0-20 BaO 0-20 CaO + SrO + BaO 0-25 Sb.sub.2 O.sub.3 0-61 Bi.sub.2 O.sub.3 0-10 Sb.sub.2 O.sub.3 + Bi.sub.2 O.sub.3 0-61 Sb.sub.2 O.sub.3 + Bi.sub.2 O.sub.3 + Ag.sub.2 O + Tl.sub.2 O 7-76 SnO 0-5 Al.sub.2 O.sub.3 0-5 B.sub.2 O.sub.3 0-10 Al.sub.2 O.sub.3 + B.sub.2 O.sub.3 0-10 ______________________________________
- with the provisos that:
- (a) in the absence of Sb.sub.2 O.sub.3 and/or Bi.sub.2 O.sub.3, the total Ag.sub.2 O+Tl.sub.2 O will range 11-25;
- (b) in the absence of Ag20 and/or Tl.sub.2 O, the total Sb.sub.2 O.sub.3 +Bi.sub.2 O.sub.3 will range 7-61;
- (c) when present in the absence of Bi.sub.2 O and/or Ag.sub.2 O and/or Tl.sub.2 O, Sb.sub.3 O.sub.3 will range 10-61 and, when present in the absence of Sb.sub.2 O.sub.3 and/or Ag.sub.2 O and/or Tl.sub.2 O, Bi.sub.2 O.sub.3 will range 7-10;
- (d) when present in the absence of Bi.sub.2 O.sub.3, Sb.sub.2 O.sub.3, and Tl.sub.2 O, Ag.sub.2 O will range 13-25;
- and
- (e) when present in the absence of Ag.sub.2 O, Bi.sub.2 O.sub.3, and Sb.sub.2 O.sub.3, Tl.sub.2 O will range 11-25.
A lens prepared from a glass having a composition which is essentially fluorine-free and which exhibits an annealing point between 300.degree.-340.degree. C., a linear coefficient of thermal expansion over the temperature interval 25.degree.-300.degree. C. between 135-180.times.10.sup.-7 /.degree.C., a refractive index of at least 1.65, and a weight loss after exposure to boiling water for six hours no greater than 0.33% consisting essentially, expressed in terms of mole percent on the oxide basis, of:
- ______________________________________ P.sub.2 O.sub.5 24-36 ZnO 0-45 Li.sub.2 O 0-15 Na.sub.2 O 0-20 K.sub.2 O 0-10 Ag.sub.2 O 0-25 Tl.sub.2 O 0-25 Li.sub.2 O + Na.sub.2 O + K.sub.2 O + Ag.sub.2 O + Tl.sub.2 O 15-30 PbO 0-20 CaO 0-20 CuO 0-5 CeO.sub.2 0-2 SrO 0-20 BaO 0-20 CaO + SrO + BaO 0-25 Sb.sub.2 O.sub.3 0-61 Bi.sub.2 O.sub.3 0-10 Sb.sub.2 O.sub.3 + Bi.sub.2 O.sub.3 0-61 Sb.sub.2 O.sub.3 + Bi.sub.2 O.sub.3 + Ag.sub.2 O + Tl.sub.2 O 7-76 SnO 0-5 Al.sub.2 O.sub.3 0-5 B.sub.2 O.sub.3 0-10 Al.sub.2 O.sub.3 + B.sub.2 O.sub.3 0-10 ______________________________________
- with the provisos that:
- (a) in the absence of Sb.sub.2 O.sub.3 and/or Bi.sub.2 O.sub.3, the total Ag.sub.2 O+Tl.sub.2 O will range 11-25;
- (b) in the absence of Ag.sub.2 O and/or Tl.sub.2 O, the total Sb.sub.2 O.sub.3 +Bi.sub.2 O.sub.3 will range 714 61;
- (c) when present in the absence of Bi.sub.2 O.sub.3 and/or Ag.sub.2 O and/or Tl.sub.2 O, Sb.sub.2 O.sub.3 will range 10-61 and, when present in the absence of Sb.sub.2 O.sub.3 and/or Ag.sub.2 O and/or Tl.sub.2 O.sub.3 will range 7-10;
- (d) when present in the absence of Bi.sub.2 O.sub.3, Sb.sub.2 O.sub.3, and Tl.sub.2 O, Ag.sub.2 O will range 13-25;
- and
- (e) when present in the absence of Ag.sub.2 O, Bi.sub.2 O.sub.3, and Sb.sub.2 O.sub.3, Tl.sub.2 O will range 11-25.
Dependencies are inferred from the claim text.