US4520115A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High absorbance Pb-containing glass for cathode ray tube picture screen
Assignee: Schott AG
•
Filing: 1983-08-02
•
Granted: 1985-05-28
•
Expires: 2003-08-02
Abstract
Abstract These objects have been attained by providing highly absorbent lead containing alkali metal silicate glasses for cathode ray tube image screens, having a linear absorption coefficient mu of >30 cm-1 (0.6 ANGSTROM ) and with a high resistance to discoloration by X-ray and electron radiation, comprises, in weight percent: -SiO2 20-65% -P2O5 + B2O3 + Al2O3 0-30% -Li2O 0-5% -Na2O 0-10% -K2O 0-15% -MgO + CaO + ZnO 0-15% -SrO 0-20% -BaO 0-40% -PbO 5-60% -ZrO2 0-10% -CeO2 0.1-5% -Other Components 0-20%. -
Inventors
- 👤 Burkhard Speit
- 👤 Karl Mennemann
- 👤 Georg Gliemeroth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:28
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/863; C; C03; C03C; C03C3/00; C03C3/04; C03C3/062; C03C3/07; C03C3/076; C03C3/102; C03C4/00; C03C4/08; C03C4/087
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
142 words
A highly absorbent lead-containing alkali metal silicate glass useful for cathode ray tube image screens, having a linear X-ray absorption coefficient μ of >30 cm -1 (0.6Å), and a high resistance to discoloration by X-ray and electron radiation, consisting essentially of, in weight percent: ______________________________________
SiO.sub.2 30-60%
P.sub.2 O.sub.5 + B.sub.2 O.sub.3 + Al.sub.2 O.sub.3
0-15%
Li.sub.2 O 0-5%
Na.sub.2 O 1-2.9%
5-10.8%
K.sub.2 O 4-8.5%
MgO + CaO + ZnO 0-8%
SrO + BaO 0-40%
20-60%
PbO 5-50%
ZrO.sub.2 0-8%
CeO.sub.2 1.0-3.5%
and 0-20% in total of
La.sub.2 O.sub.3 + Y.sub.2 O.sub.3 +
0-15%
Bi.sub.2 O.sub.3 + SnO
S + Se + Te 0-5%
F + Cl + Br + SO.sub.4
0-3%
TiO.sub.2 0-5%
rare earth metal oxides
0-3%
atomic numbers 58-91
Fe.sub.2 O.sub.3 + Cr.sub.2 O.sub.3 +
0-1%
MnO + NiO + CoO
As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3
0-2%.
______________________________________
Claim 2
Dependent Claim
142 words
A highly absorbent lead-containing alkali metal silicate glass useful for cathode ray tube image screens, having a linear X-ray absorption coefficient μ of >30 cm -1 (0.6Å), and a high resistance to discoloration by X-ray and electron radiation, consisting essentially of, in weight percent: ______________________________________
SiO.sub.2 30-60%
P.sub.2 O.sub.5 + B.sub.2 O.sub.3 + Al.sub.2 O.sub.3
0-15%
Li.sub.2 O 0-5%
Na.sub.2 O 1-2.9%
5-10.8%
K.sub.2 O 4-8.5%
MgO + CaO + ZnO 0-8%
SrO + BaO 0-40%
20-60%
PbO 5-50%
ZrO.sub.2 0-8%
CeO.sub.2 1.0-3.5%
and 0-20% in total of
La.sub.2 O.sub.3 + Y.sub.2 O.sub.3 +
0-15%
Bi.sub.2 O.sub.3 + SnO
S + Se + Te 0-5%
F + Cl + Br + SO.sub.4
0-3%
TiO.sub.2 0-5%
rare earth metal oxides
0-3%
atomic numbers 58-91
Fe.sub.2 O.sub.3 + Cr.sub.2 O.sub.3 +
0-1%
MnO + NiO + CoO
As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3
0-2%.
______________________________________
Claim 3
Dependent Claim
32 words
A glass of claim 1 containing an amount of La 2 O 3 , Y 2 O 3 , Bi 2 O 3 or SnO up to 15% by weight in total.
Claim 4
Dependent Claim
20 words
A glass of claim 1 containing an amount of S, Se or Te up to 5% by weight in total.
Claim 5
Dependent Claim
21 words
A glass of claim 1 containing an amount of F, Cl, Br or SO 4 2- 0.2-3% by weight in total.
Claim 6
Dependent Claim
36 words
A glass of claim 1 containing an amount of TiO 2 up to 5% by weight, and an amount of a rare earth with an atomic number of 58-91, up to 3% by weight in total.
Claim 7
Dependent Claim
30 words
A glass of claim 1 containing an amount of Fe 2 O 3 , Cr 2 O 3 , MnO, NiO or CoO up to 1% by weight in total.
Claim 8
Dependent Claim
25 words
A glass of claim 1 containing an amount of As 2 O 3 or Sb 2 O 3 up to 2% by weight in total.
Claim 9
Dependent Claim
67 words
A glass of claim 1 having the following properties: electrical resistivity at 300° C.: at least 10 8 Ω cm; coefficient of thermal expansion α at 20°-300° C.: no more than 100×10 7 /°C.; transformation temperature: 420° to 500° C.; processing temperature: 900° C. to 1000° C.; linear absorption coefficient for X-rays at 0.6Å: at least 60 cm -1 ; density: more than 3.0 g/cm 3 .
Claim 10
Dependent Claim
15 words
A glass of claim 1 wherein the amount of CeO 2 is 1-3% of weight.
Claim 11
Dependent Claim
12 words
A glass of claim 1 wherein the weight ratio Li:Na:K is 1:3-4:12-16.
Claim 12
Dependent Claim
26 words
An image plate for CRT's consisting essentially of a glass of claim 1 and having a high resistance to browning by irradiation with electrons and X-rays.
Claim 13
Dependent Claim
14 words
A glass of claim 1, wherein the amount of PbO is 12.9-50 wt %.
Claim 14
Dependent Claim
13 words
A glass of claim 1, wherein the amount of CeO 2 is 2.0-3.5%.
Claim 15
Dependent Claim
12 words
A glass of claim 1, wherein the amount of SrO is 0-14%.
References Cited (Backward Citations)
BE451565A
Cited
US1703391A
Cited
US1632534A
Cited
US2025099A
Cited
US2477329A
Cited
US2782319A
Cited
US2747105A
Cited
GB734444A
Cited
US2856303A
Cited
US2948992A
Cited
US2901366A
Cited
GB870101A
Cited
GB946030A
Cited
US3356579A
Cited
US3369961A
Cited
US3422298A
Cited
GB1123857A
Cited
US3382393A
Cited
US3461078A
Cited
US3464932A
Cited
GB1231378A
Cited
US4065697A
Cited
US4065696A
Cited
US3805107A
Cited
NL7301999A
Cited
JPS5029618A
Cited
US3987330A
Cited
US4174490A
Cited
US4179638A
Cited
JPS55113644A
Cited
US4376829A
Cited
US4390637A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-27 | 1988-11-26 | 1989-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-27 | 1992-11-26 | 1993-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-27 | 1996-11-26 | 1997-05-28 | $7700.00 | Window Closed / Lapsed |