US3964918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Barium borosilicate optical glasses
Assignee: Corning Glass Works
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Filing: 1974-12-06
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Granted: 1976-06-22
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Expires: 1994-12-06
Abstract
Abstract A dense barium borosilicate glass is disclosed having a refractive index greater than 1.64 and a dispersive index of at least 53, together with a high degree of chemical durability such that optical blanks molded from the glass can be finished on automatic machinery with minimal danger of staining. The glass consists essentially of 18-30% SiO 2 , 8-22% B 2 O 3 , 25-48% BaO, 0-10% other divalent metal oxides, 25-45% total divalent metal oxides, 10-30% La 2 O 3 , 0-6% ZrO 2 and/or SnO 2 , with the mole ratio of BaO:SiO 2 not exceeding 0.6 and preferably not exceeding 0.5.
Inventors
- 👤 George B. Hares
- 👤 David W. Morgan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:53
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/062; C03C3/064; C03C3/068; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/903
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
104 words
A lanthana-baria-borosilicate optical glass having a refractive index greater than 1.64, a dispersive index of at least 53, a weight loss not exceeding 1 mg./cm. 2 when immersed in a 10% HCl solution at room temperature for ten minutes, and being composed essentially of, as calculated from the batch in weight percent on an oxide basis, 18-36% SiO 2 , 8-22% B 2 O 3 , 25-48% BaO, 0-10% of the other divalent metal oxides ZnO, PbO, and/or CaO, the total divalent metal oxide (RO) content being 25-48%, and 10-30% La 2 O 3 , the mole ratio of RO:SiO 2 not exceeding 0.6.
Claim 2
Dependent Claim
104 words
A lanthana-baria-borosilicate optical glass having a refractive index greater than 1.64, a dispersive index of at least 53, a weight loss not exceeding 1 mg./cm. 2 when immersed in a 10% HCl solution at room temperature for ten minutes, and being composed essentially of, as calculated from the batch in weight percent on an oxide basis, 18-36% SiO 2 , 8-22% B 2 O 3 , 25-48% BaO, 0-10% of the other divalent metal oxides ZnO, PbO, and/or CaO, the total divalent metal oxide (RO) content being 25-48%, and 10-30% La 2 O 3 , the mole ratio of RO:SiO 2 not exceeding 0.6.
Claim 3
Dependent Claim
18 words
A glass in accordance with claim 1 containing up to 6% of ZrO 2 and/or SnO 2 .
Claim 4
Dependent Claim
18 words
A glass in accordance with claim 1 wherein the mole ratio of BaO:SiO 2 does not exceed 0.5.
Claim 5
Dependent Claim
25 words
A glass in accordance with claim 1 having a refractive index greater than 1.67 and an La 2 O 3 content of at least 15%.
Claim 6
Dependent Claim
25 words
A glass in accordance with claim 1 having a refractive index greater than 1.68 and an La 2 O 3 content of at least 20%.
Claim 7
Dependent Claim
15 words
A glass in accordance with claim 1 wherein the BaO content is not over 45%.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-22 | 1979-12-22 | 1980-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-22 | 1983-12-22 | 1984-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-22 | 1987-12-22 | 1988-06-22 | $7700.00 | Window Closed / Lapsed |