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US4721690A
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High PbO-content glasses in the system SiO2 --PbO--M2 O with increased chemical stability
Assignee: Schott AG
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Filing: 1985-02-05
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Granted: 1988-01-26
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Expires: 2005-02-05
Abstract
Abstract High PbO-content glass in the optical range of flint and heavy flint glasses from the system SiO2-PbO-M2O wherein M2O=alkali metal oxides, said glass having a minimum PbO content of 30 wt. % and a minimum M2O content of 0.5 wt. %, are provided with enhanced chemical stability without loss of the desired optical position by replacing a portion of the SiO2 and PbO such that the glass contains 1.5-6 wt. % (TiO2+ZrO2) and the ratio of TiO2:ZrO2 is about 0.3-2.0.
Inventors
- 👤 Ludwig Ross
- 👤 Danuta Grabowski
- 👤 Burkhard Speit
- 👤 Volkmar Geiler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:39
CPC Classifications
C; C03; C03C; C03C4/00; C03C4/0028; C03C3/00; C03C3/04; C03C3/062; C03C3/07; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/901; Y10S501/903
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
151 words
A high PbO-content optical glass with optical properties of the heavy flint (SF) region of the Abbe--diagram of FIG. 2 wherein the glass has a refractive index n d of 1.65-1.85, an Abbe number v d of 35-25, an acid resistance of SR class 1-2 and consists essentially of the following composition, in weight%: SiO 2 15-60 PbO 30-80 M 2 O 0.5-15 (M 2 O=Na 2 O, K 2 O, Cs 2 O) ZrO 2 0.9-4 TiO 2 0.6-2 wherein ZrO 2 +TiO 2 =1.5-6 and TiO 2 :ZrO 2 =0.3-2.0, As 2 O 3 0.1-0.5 F - 0-0.5 and up to 20 wt.% of the following further components: ______________________________________
alkaline earth metal oxides + ZnO
0.5-5
B.sub.2 O.sub.3 0.5-8
Al.sub.2 O.sub.3 1-3
GeO.sub.2 0.1-2
La.sub.2 O.sub.3 0.5-4
Bi.sub.2 O.sub.3 0.5-8
TeO.sub.2 0.1-2
CeO.sub.2 0.1-2
WO.sub.3 0.1-2
Y.sub.2 O.sub.3 0.5-5
Gd.sub.2 O.sub.3 0.5-10
Ta.sub.2 O.sub.5 0.2-2
Nb.sub.2 O.sub.5 0.5-3.
______________________________________
Claim 2
Dependent Claim
151 words
A high PbO-content optical glass with optical properties of the heavy flint (SF) region of the Abbe--diagram of FIG. 2 wherein the glass has a refractive index n d of 1.65-1.85, an Abbe number v d of 35-25, an acid resistance of SR class 1-2 and consists essentially of the following composition, in weight%: SiO 2 15-60 PbO 30-80 M 2 O 0.5-15 (M 2 O=Na 2 O, K 2 O, Cs 2 O) ZrO 2 0.9-4 TiO 2 0.6-2 wherein ZrO 2 +TiO 2 =1.5-6 and TiO 2 :ZrO 2 =0.3-2.0, As 2 O 3 0.1-0.5 F - 0-0.5 and up to 20 wt.% of the following further components: ______________________________________
alkaline earth metal oxides + ZnO
0.5-5
B.sub.2 O.sub.3 0.5-8
Al.sub.2 O.sub.3 1-3
GeO.sub.2 0.1-2
La.sub.2 O.sub.3 0.5-4
Bi.sub.2 O.sub.3 0.5-8
TeO.sub.2 0.1-2
CeO.sub.2 0.1-2
WO.sub.3 0.1-2
Y.sub.2 O.sub.3 0.5-5
Gd.sub.2 O.sub.3 0.5-10
Ta.sub.2 O.sub.5 0.2-2
Nb.sub.2 O.sub.5 0.5-3.
______________________________________
Claim 3
Dependent Claim
10 words
Glass according to claim 1 containing at least 45% PbO.
Claim 4
Dependent Claim
8 words
Glass according to claim 1 containing 50-80% PbO.
Claim 5
Dependent Claim
10 words
Glass according to claim 1 containing 25-60% SiO 2 .
Claim 6
Dependent Claim
29 words
Glass according to claim 1 further characterized by containing (TiO 2 +ZrO 2 ) in an amount of 2.0-5.5 wt.% at a TiO 2 :ZrO 2 ratio of 0.4-1.5.
Claim 7
Dependent Claim
46 words
Glass according to claim 1 consisting essentially of the following composition, in wt.%: ______________________________________
SiO.sub.2
27-45
PbO 57-65
M.sub.2 O
0.8-10 (M.sub.2 O = Na.sub.2 O, K.sub.2 O, Cs.sub.2 O)
ZrO.sub.2
1.2-3.8
TiO.sub.2
0.8-1.7
As.sub.2 O.sub.3
0.2-0.3
F.sup.- 0-0.3 and wherein
TiO.sub.2 :ZrO.sub.2 = 0.4-1.5.
______________________________________
Claim 8
Dependent Claim
42 words
In an article of manufacture comprising optical glass, ophthalmic glass, radiation-protection glass, videoscreen glass, electrode glass, sounding glass, technical glass, optical or technical glass fibers, or lead crystal glass, the improvement wherein the glass component is a composition according to claim 1.
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