Patent US4213787A successfully refreshed from Google Patents.
US4213787A
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High refractive index glasses of limited specific gravity for distance and near vision spectacle lenses
Assignee: Schott AG
•
Filing: 1979-06-05
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Granted: 1980-07-22
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Expires: 1999-06-05
Abstract
Abstract Optical glasses having high refractive indexes and low specific gravities are provided for use as both distant and near vision spectacle lenses. The glasses consist essentially of low molecular weight cationic oxides, alkali metal oxides and divalent oxides to promote the crystallization stability of the glass. They have good chemical resistance, chemical hardenability and a thermal expansion coefficient between 93 and 99×10 -7 /° C. in the range of 20°-300° C. Optical lenses can be continuously produced due to the high crystallization stability of the glasses and the resultant spectacle lenses have high dioptric values even with thinner edge or center thicknesses.
Inventors
- 👤 Marga Faulstich
- 👤 Volkmar Geiler
- 👤 Georg Gliemeroth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:13
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/062; C03C3/064; C03C3/066; C03C3/068; C03C3/07; C03C3/072; C03C3/074; G; G07; G07C; G07C9/00; G07C9/00174; G07C9/00658; G07C9/00722; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/901; Y10T; Y10T70/00; Y10T70/70; Y10T70/7441; Y10T70/778; Y10T70/7791; Y10T70/7802; Y10T70/7819; Y10T70/7904
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
124 words
Optical glasses suitable for use as spectacle lenses having a refractive index nd=1.79-1.81, a dispersion vd=31-29 and a specific gravity s=3.4-3.7, consisting essentially of the following composition: ______________________________________
Oxides Weight Percent
______________________________________
SiO.sub.2 25-35
TiO.sub.2 10-15
28-35
Nb.sub.2 O.sub.5 18-24
ZrO.sub.2 3-9
SrO 0-7
12-20
BaO 7-20
B.sub.2 O.sub.3 0-7
Li.sub.20 5-8
Na.sub.2 O 0-3 5-9
K.sub.2 O 0-2
MgO 0-2
0-5
CaO 0-5
ZnO 0-4
PbO 0-3
Al.sub.2 O.sub.3 0-2
La.sub.2 O.sub.3 0-5
Ta.sub.2 O.sub.5 0-4
Gd.sub.2 O.sub.3, Y.sub.2 O.sub.3,
Bi.sub.2 O.sub.3, WO.sub.3
0-3; and
refining agent 0.2-1,
______________________________________ said glasses having high crystallization stability as determined by the magnitude of crystal growth speed and the crystallization temperature range in relation to the viscosity in order to permit continuous production of said lenses.
Claim 2
Dependent Claim
124 words
Optical glasses suitable for use as spectacle lenses having a refractive index nd=1.79-1.81, a dispersion vd=31-29 and a specific gravity s=3.4-3.7, consisting essentially of the following composition: ______________________________________
Oxides Weight Percent
______________________________________
SiO.sub.2 25-35
TiO.sub.2 10-15
28-35
Nb.sub.2 O.sub.5 18-24
ZrO.sub.2 3-9
SrO 0-7
12-20
BaO 7-20
B.sub.2 O.sub.3 0-7
Li.sub.20 5-8
Na.sub.2 O 0-3 5-9
K.sub.2 O 0-2
MgO 0-2
0-5
CaO 0-5
ZnO 0-4
PbO 0-3
Al.sub.2 O.sub.3 0-2
La.sub.2 O.sub.3 0-5
Ta.sub.2 O.sub.5 0-4
Gd.sub.2 O.sub.3, Y.sub.2 O.sub.3,
Bi.sub.2 O.sub.3, WO.sub.3
0-3; and
refining agent 0.2-1,
______________________________________ said glasses having high crystallization stability as determined by the magnitude of crystal growth speed and the crystallization temperature range in relation to the viscosity in order to permit continuous production of said lenses.
Claim 3
Dependent Claim
71 words
Optical glasses according to claim 1, consisting essentially of the following composition: ______________________________________
Oxides Percent by Weight
______________________________________
SiO.sub.2 26-28
TiO.sub.2 10-14
30-33
Nb.sub.2 O.sub.5 18-23
ZrO.sub.2 3-6
SrO 5-7
16-18
BaO 9-12
B.sub.2 O.sub.3 3-5
Li.sub.2 O 6-8
7-8
Na.sub.2 O 1-2
CaO 0-3
ZnO 0-2
PbO 0-2
Al.sub.2 O.sub.3 0-1
La.sub.2 O.sub.3 0-4
Ta.sub.2 O.sub.5 0-2
As.sub.2 O.sub.3 0.1-1
Gd.sub.2 O.sub.3, Y.sub.2 O.sub.3,
Bi.sub.2 O.sub.3 and WO.sub.3
0-2
______________________________________
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-07-22 | 1984-01-21 | 1984-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-22 | 1988-01-21 | 1988-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-22 | 1992-01-21 | 1992-07-22 | $7700.00 | Window Closed / Lapsed |